ntp-keygen.html revision 344884
1<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 2<html> 3<!-- Created by GNU Texinfo 6.5, http://www.gnu.org/software/texinfo/ --> 4<head> 5<meta http-equiv="Content-Type" content="text/html; charset=utf-8"> 6<title>Ntp-keygen User’s Manual</title> 7 8<meta name="description" content="Ntp-keygen User’s Manual"> 9<meta name="keywords" content="Ntp-keygen User’s Manual"> 10<meta name="resource-type" content="document"> 11<meta name="distribution" content="global"> 12<meta name="Generator" content="makeinfo"> 13<link href="#Top" rel="start" title="Top"> 14<link href="dir.html#Top" rel="up" title="(dir)"> 15<style type="text/css"> 16<!-- 17a.summary-letter {text-decoration: none} 18blockquote.indentedblock {margin-right: 0em} 19blockquote.smallindentedblock {margin-right: 0em; font-size: smaller} 20blockquote.smallquotation {font-size: smaller} 21div.display {margin-left: 3.2em} 22div.example {margin-left: 3.2em} 23div.lisp {margin-left: 3.2em} 24div.smalldisplay {margin-left: 3.2em} 25div.smallexample {margin-left: 3.2em} 26div.smalllisp {margin-left: 3.2em} 27kbd {font-style: oblique} 28pre.display {font-family: inherit} 29pre.format {font-family: inherit} 30pre.menu-comment {font-family: serif} 31pre.menu-preformatted {font-family: serif} 32pre.smalldisplay {font-family: inherit; font-size: smaller} 33pre.smallexample {font-size: smaller} 34pre.smallformat {font-family: inherit; font-size: smaller} 35pre.smalllisp {font-size: smaller} 36span.nolinebreak {white-space: nowrap} 37span.roman {font-family: initial; font-weight: normal} 38span.sansserif {font-family: sans-serif; font-weight: normal} 39ul.no-bullet {list-style: none} 40--> 41</style> 42 43 44</head> 45 46<body lang="en"> 47<h1 class="settitle" align="center">Ntp-keygen User’s Manual</h1> 48 49 50 51 52 53<a name="SEC_Overview"></a> 54<h2 class="shortcontents-heading">Short Table of Contents</h2> 55 56<div class="shortcontents"> 57<ul class="no-bullet"> 58<li><a name="stoc-Description-1" href="#toc-Description-1">1 Description</a></li> 59</ul> 60</div> 61 62 63<table class="menu" border="0" cellspacing="0"> 64<tr><td align="left" valign="top">• <a href="#Description" accesskey="1">Description</a>:</td><td> </td><td align="left" valign="top"> 65</td></tr> 66<tr><td align="left" valign="top">• <a href="#ntp_002dkeygen-Invocation" accesskey="2">ntp-keygen Invocation</a>:</td><td> </td><td align="left" valign="top">Invoking ntp-keygen 67</td></tr> 68<tr><td align="left" valign="top">• <a href="#Running-the-Program" accesskey="3">Running the Program</a>:</td><td> </td><td align="left" valign="top"> 69</td></tr> 70<tr><td align="left" valign="top">• <a href="#Random-Seed-File" accesskey="4">Random Seed File</a>:</td><td> </td><td align="left" valign="top"> 71</td></tr> 72<tr><td align="left" valign="top">• <a href="#Cryptographic-Data-Files" accesskey="5">Cryptographic Data Files</a>:</td><td> </td><td align="left" valign="top"> 73</td></tr> 74</table> 75 76<a name="Top"></a> 77<div class="header"> 78<p> 79Next: <a href="#Description" accesskey="n" rel="next">Description</a>, Previous: <a href="dir.html#Top" accesskey="p" rel="prev">(dir)</a>, Up: <a href="dir.html#Top" accesskey="u" rel="up">(dir)</a> </p> 80</div> 81<a name="NTP-Key-Generation-Program-User-Manual"></a> 82<h1 class="top">NTP Key Generation Program User Manual</h1> 83 84<p>This document describes the use of the NTP Project’s <code>ntp-keygen</code> 85program, that generates cryptographic data files used by the NTPv4 86authentication and identity schemes. 87It can generate message digest keys used in symmetric key cryptography and, 88if the OpenSSL software 89library has been installed, it can generate host keys, sign keys, 90certificates, and identity keys and parameters used by the Autokey 91public key cryptography. 92The message digest keys file is generated in a 93format compatible with NTPv3. 94All other files are in PEM-encoded 95printable ASCII format so they can be embedded as MIME attachments in 96mail to other sites. 97</p> 98<p>This document applies to version 4.2.8p13 of <code>ntp-keygen</code>. 99</p> 100<table class="menu" border="0" cellspacing="0"> 101<tr><td align="left" valign="top">• <a href="#Description" accesskey="1">Description</a>:</td><td> </td><td align="left" valign="top"> 102</td></tr> 103</table> 104 105<hr> 106<a name="Description"></a> 107<div class="header"> 108<p> 109Next: <a href="#Running-the-Program" accesskey="n" rel="next">Running the Program</a>, Previous: <a href="#Top" accesskey="p" rel="prev">Top</a>, Up: <a href="#Top" accesskey="u" rel="up">Top</a> </p> 110</div> 111<a name="Description-1"></a> 112<h2 class="chapter">1 Description</h2> 113 114<p>This program generates cryptographic data files used by the NTPv4 115authentication and identity schemes. It can generate message digest 116keys used in symmetric key cryptography and, if the OpenSSL software 117library has been installed, it can generate host keys, sign keys, 118certificates, and identity keys and parameters used by the Autokey 119public key cryptography. The message digest keys file is generated in a 120format compatible with NTPv3. All other files are in PEM-encoded 121printable ASCII format so they can be embedded as MIME attachments in 122mail to other sites. 123</p> 124<p>When used to generate message digest keys, the program produces a file 125containing ten pseudo-random printable ASCII strings suitable for the 126MD5 message digest algorithm included in the distribution. 127If the 128OpenSSL library is installed, it produces an additional ten hex-encoded 129random bit strings suitable for the SHA1 and other message digest 130algorithms. 131The message digest keys file must be distributed and stored 132using secure means beyond the scope of NTP itself. 133Besides the keys 134used for ordinary NTP associations, additional keys can be defined as 135passwords for the ntpq and ntpdc utility programs. 136</p> 137<p>The remaining generated files are compatible with other OpenSSL 138applications and other Public Key Infrastructure (PKI) resources. 139Certificates generated by this program are compatible with extant 140industry practice, although some users might find the interpretation of 141X509v3 extension fields somewhat liberal. 142However, the identity keys 143are probably not compatible with anything other than Autokey. 144</p> 145<p>Some files used by this program are encrypted using a private password. 146The <code>-p</code> option specifies the password for local encrypted files and the 147<code>-q</code> option the password for encrypted files sent to remote sites. 148If no password is specified, the host name returned by the Unix 149<code>gethostname()</code> function, normally the DNS name of the host, is used. 150</p> 151<p>The <kbd>pw</kbd> option of the <code>crypto</code> configuration command 152specifies the read password for previously encrypted local files. 153This must match the local password used by this program. 154If not specified, the host name is used. 155Thus, if files are generated by this program without password, 156they can be read back by ntpd without password, but only on the same 157host. 158</p> 159<p>Normally, encrypted files for each host are generated by that host and 160used only by that host, although exceptions exist as noted later on 161this page. 162The symmetric keys file, normally called <code>ntp.keys</code>, is 163usually installed in <code>/etc</code>. 164Other files and links are usually installed 165in <code>/usr/local/etc</code>, which is normally in a shared filesystem in 166NFS-mounted networks and cannot be changed by shared clients. 167The location of the keys directory can be changed by the keysdir 168configuration command in such cases. 169Normally, this is in <code>/etc</code>. 170</p> 171<p>This program directs commentary and error messages to the standard 172error stream <code>stderr</code> and remote files to the standard output stream 173<code>stdout</code> where they can be piped to other applications or redirected to 174files. 175The names used for generated files and links all begin with the 176string <code>ntpkey</code> and include the file type, 177generating host and filestamp, 178as described in the <a href="#Cryptographic-Data-Files">Cryptographic Data Files</a> section below. 179</p> 180<table class="menu" border="0" cellspacing="0"> 181<tr><td align="left" valign="top">• <a href="#Running-the-Program" accesskey="1">Running the Program</a>:</td><td> </td><td align="left" valign="top"> 182</td></tr> 183<tr><td align="left" valign="top">• <a href="#ntp_002dkeygen-Invocation" accesskey="2">ntp-keygen Invocation</a>:</td><td> </td><td align="left" valign="top"> 184</td></tr> 185<tr><td align="left" valign="top">• <a href="#Random-Seed-File" accesskey="3">Random Seed File</a>:</td><td> </td><td align="left" valign="top"> 186</td></tr> 187<tr><td align="left" valign="top">• <a href="#Cryptographic-Data-Files" accesskey="4">Cryptographic Data Files</a>:</td><td> </td><td align="left" valign="top"> 188</td></tr> 189</table> 190 191<hr> 192<a name="Running-the-Program"></a> 193<div class="header"> 194<p> 195Next: <a href="#Random-Seed-File" accesskey="n" rel="next">Random Seed File</a>, Previous: <a href="#Description" accesskey="p" rel="prev">Description</a>, Up: <a href="#Top" accesskey="u" rel="up">Top</a> </p> 196</div> 197<a name="Running-the-Program-1"></a> 198<h3 class="section">1.1 Running the Program</h3> 199 200<p>To test and gain experience with Autokey concepts, log in as root and 201change to the keys directory, usually <code>/usr/local/etc</code>. 202When run for the 203first time, or if all files with names beginning <code>ntpkey</code>] have been 204removed, use the <code>ntp-keygen</code> command without arguments to generate a 205default RSA host key and matching RSA-MD5 certificate with expiration 206date one year hence. 207If run again without options, the program uses the 208existing keys and parameters and generates only a new certificate with 209new expiration date one year hence. 210</p> 211<p>Run the command on as many hosts as necessary. 212Designate one of them as the trusted host (TH) using <code>ntp-keygen</code> 213with the <code>-T</code> option and configure 214it to synchronize from reliable Internet servers. 215Then configure the other hosts to synchronize to the TH directly or indirectly. 216A certificate trail is created when Autokey asks the immediately 217ascendant host towards the TH to sign its certificate, which is then 218provided to the immediately descendant host on request. 219All group hosts should have acyclic certificate trails ending on the TH. 220</p> 221<p>The host key is used to encrypt the cookie when required and so must be 222RSA type. 223By default, the host key is also the sign key used to encrypt signatures. 224A different sign key can be assigned using the <code>-S</code> option 225and this can be either RSA or DSA type. 226By default, the signature 227message digest type is MD5, but any combination of sign key type and 228message digest type supported by the OpenSSL library can be specified 229using the <code>-c</code> option. 230</p> 231<p>The rules say cryptographic media should be generated with proventic 232filestamps, which means the host should already be synchronized before 233this program is run. 234This of course creates a chicken-and-egg problem 235when the host is started for the first time. 236Accordingly, the host time 237should be set by some other means, such as eyeball-and-wristwatch, at 238least so that the certificate lifetime is within the current year. 239After that and when the host is synchronized to a proventic source, the 240certificate should be re-generated. 241</p> 242<p>Additional information on trusted groups and identity schemes is on the 243Autokey Public-Key Authentication page. 244</p> 245<hr> 246<a name="ntp_002dkeygen-Invocation"></a> 247<div class="header"> 248<p> 249Next: <a href="#Random-Seed-File" accesskey="n" rel="next">Random Seed File</a>, Previous: <a href="#Running-the-Program" accesskey="p" rel="prev">Running the Program</a>, Up: <a href="#Description" accesskey="u" rel="up">Description</a> </p> 250</div> 251<a name="Invoking-ntp_002dkeygen"></a> 252<h3 class="section">1.2 Invoking ntp-keygen</h3> 253<a name="index-ntp_002dkeygen"></a> 254<a name="index-Create-a-NTP-host-key"></a> 255 256 257 258<p>This program generates cryptographic data files used by the NTPv4 259authentication and identification schemes. 260It can generate message digest keys used in symmetric key cryptography and, 261if the OpenSSL software library has been installed, it can generate host keys, 262signing keys, certificates, and identity keys and parameters used in Autokey 263public key cryptography. 264These files are used for cookie encryption, 265digital signature, and challenge/response identification algorithms 266compatible with the Internet standard security infrastructure. 267</p> 268<p>The message digest symmetric keys file is generated in a format 269compatible with NTPv3. 270All other files are in PEM-encoded printable ASCII format, 271so they can be embedded as MIME attachments in email to other sites 272and certificate authorities. 273By default, files are not encrypted. 274</p> 275<p>When used to generate message digest symmetric keys, the program 276produces a file containing ten pseudo-random printable ASCII strings 277suitable for the MD5 message digest algorithm included in the 278distribution. 279If the OpenSSL library is installed, it produces an additional ten 280hex-encoded random bit strings suitable for SHA1, AES-128-CMAC, and 281other message digest algorithms. 282The message digest symmetric keys file must be distributed and stored 283using secure means beyond the scope of NTP itself. 284Besides the keys used for ordinary NTP associations, additional keys 285can be defined as passwords for the 286<code>ntpq(1ntpqmdoc)</code> 287and 288<code>ntpdc(1ntpdcmdoc)</code> 289utility programs. 290</p> 291<p>The remaining generated files are compatible with other OpenSSL 292applications and other Public Key Infrastructure (PKI) resources. 293Certificates generated by this program are compatible with extant 294industry practice, although some users might find the interpretation of 295X509v3 extension fields somewhat liberal. 296However, the identity keys are probably not compatible with anything 297other than Autokey. 298</p> 299<p>Some files used by this program are encrypted using a private password. 300The 301<code>-p</code> 302option specifies the read password for local encrypted files and the 303<code>-q</code> 304option the write password for encrypted files sent to remote sites. 305If no password is specified, the host name returned by the Unix 306<code>hostname(1)</code> 307command, normally the DNS name of the host, is used as the the default read 308password, for convenience. 309The 310<code>ntp-keygen</code> 311program prompts for the password if it reads an encrypted file 312and the password is missing or incorrect. 313If an encrypted file is read successfully and 314no write password is specified, the read password is used 315as the write password by default. 316</p> 317<p>The 318<code>pw</code> 319option of the 320<code>crypto</code> 321<code>ntpd(1ntpdmdoc)</code> 322configuration command specifies the read 323password for previously encrypted local files. 324This must match the local read password used by this program. 325If not specified, the host name is used. 326Thus, if files are generated by this program without an explicit password, 327they can be read back by 328<code>ntpd(1ntpdmdoc)</code> 329without specifying an explicit password but only on the same host. 330If the write password used for encryption is specified as the host name, 331these files can be read by that host with no explicit password. 332</p> 333<p>Normally, encrypted files for each host are generated by that host and 334used only by that host, although exceptions exist as noted later on 335this page. 336The symmetric keys file, normally called 337<samp>ntp.keys</samp>, 338is usually installed in 339<samp>/etc</samp>. 340Other files and links are usually installed in 341<samp>/usr/local/etc</samp>, 342which is normally in a shared filesystem in 343NFS-mounted networks and cannot be changed by shared clients. 344In these cases, NFS clients can specify the files in another 345directory such as 346<samp>/etc</samp> 347using the 348<code>keysdir</code> 349<code>ntpd(1ntpdmdoc)</code> 350configuration file command. 351</p> 352<p>This program directs commentary and error messages to the standard 353error stream 354<samp>stderr</samp> 355and remote files to the standard output stream 356<samp>stdout</samp> 357where they can be piped to other applications or redirected to files. 358The names used for generated files and links all begin with the 359string 360<samp>ntpkey*</samp> 361and include the file type, generating host and filestamp, 362as described in the 363<a href="#Cryptographic-Data-Files">Cryptographic Data Files</a> 364section below. 365</p> 366<table class="menu" border="0" cellspacing="0"> 367<tr><td align="left" valign="top">• <a href="#ntp_002dkeygen-usage" accesskey="1">ntp-keygen usage</a>:</td><td> </td><td align="left" valign="top"> 368</td></tr> 369<tr><td align="left" valign="top">• <a href="#ntp_002dkeygen-imbits" accesskey="2">ntp-keygen imbits</a>:</td><td> </td><td align="left" valign="top"> 370</td></tr> 371<tr><td align="left" valign="top">• <a href="#ntp_002dkeygen-certificate" accesskey="3">ntp-keygen certificate</a>:</td><td> </td><td align="left" valign="top"> 372</td></tr> 373<tr><td align="left" valign="top">• <a href="#ntp_002dkeygen-cipher" accesskey="4">ntp-keygen cipher</a>:</td><td> </td><td align="left" valign="top"> 374</td></tr> 375<tr><td align="left" valign="top">• <a href="#ntp_002dkeygen-id_002dkey" accesskey="5">ntp-keygen id-key</a>:</td><td> </td><td align="left" valign="top"> 376</td></tr> 377<tr><td align="left" valign="top">• <a href="#ntp_002dkeygen-gq_002dparams" accesskey="6">ntp-keygen gq-params</a>:</td><td> </td><td align="left" valign="top"> 378</td></tr> 379<tr><td align="left" valign="top">• <a href="#ntp_002dkeygen-host_002dkey" accesskey="7">ntp-keygen host-key</a>:</td><td> </td><td align="left" valign="top"> 380</td></tr> 381<tr><td align="left" valign="top">• <a href="#ntp_002dkeygen-iffkey" accesskey="8">ntp-keygen iffkey</a>:</td><td> </td><td align="left" valign="top"> 382</td></tr> 383<tr><td align="left" valign="top">• <a href="#ntp_002dkeygen-ident" accesskey="9">ntp-keygen ident</a>:</td><td> </td><td align="left" valign="top"> 384</td></tr> 385<tr><td align="left" valign="top">• <a href="#ntp_002dkeygen-lifetime">ntp-keygen lifetime</a>:</td><td> </td><td align="left" valign="top"> 386</td></tr> 387<tr><td align="left" valign="top">• <a href="#ntp_002dkeygen-modulus">ntp-keygen modulus</a>:</td><td> </td><td align="left" valign="top"> 388</td></tr> 389<tr><td align="left" valign="top">• <a href="#ntp_002dkeygen-md5key">ntp-keygen md5key</a>:</td><td> </td><td align="left" valign="top"> 390</td></tr> 391<tr><td align="left" valign="top">• <a href="#ntp_002dkeygen-pvt_002dcert">ntp-keygen pvt-cert</a>:</td><td> </td><td align="left" valign="top"> 392</td></tr> 393<tr><td align="left" valign="top">• <a href="#ntp_002dkeygen-password">ntp-keygen password</a>:</td><td> </td><td align="left" valign="top"> 394</td></tr> 395<tr><td align="left" valign="top">• <a href="#ntp_002dkeygen-export_002dpasswd">ntp-keygen export-passwd</a>:</td><td> </td><td align="left" valign="top"> 396</td></tr> 397<tr><td align="left" valign="top">• <a href="#ntp_002dkeygen-subject_002dname">ntp-keygen subject-name</a>:</td><td> </td><td align="left" valign="top"> 398</td></tr> 399<tr><td align="left" valign="top">• <a href="#ntp_002dkeygen-sign_002dkey">ntp-keygen sign-key</a>:</td><td> </td><td align="left" valign="top"> 400</td></tr> 401<tr><td align="left" valign="top">• <a href="#ntp_002dkeygen-trusted_002dcert">ntp-keygen trusted-cert</a>:</td><td> </td><td align="left" valign="top"> 402</td></tr> 403<tr><td align="left" valign="top">• <a href="#ntp_002dkeygen-mv_002dparams">ntp-keygen mv-params</a>:</td><td> </td><td align="left" valign="top"> 404</td></tr> 405<tr><td align="left" valign="top">• <a href="#ntp_002dkeygen-mv_002dkeys">ntp-keygen mv-keys</a>:</td><td> </td><td align="left" valign="top"> 406</td></tr> 407<tr><td align="left" valign="top">• <a href="#ntp_002dkeygen-config">ntp-keygen config</a>:</td><td> </td><td align="left" valign="top"> 408</td></tr> 409<tr><td align="left" valign="top">• <a href="#ntp_002dkeygen-exit-status">ntp-keygen exit status</a>:</td><td> </td><td align="left" valign="top"> 410</td></tr> 411<tr><td align="left" valign="top">• <a href="#ntp_002dkeygen-Usage">ntp-keygen Usage</a>:</td><td> </td><td align="left" valign="top"> 412</td></tr> 413<tr><td align="left" valign="top">• <a href="#ntp_002dkeygen-Notes">ntp-keygen Notes</a>:</td><td> </td><td align="left" valign="top"> 414</td></tr> 415<tr><td align="left" valign="top">• <a href="#ntp_002dkeygen-Bugs">ntp-keygen Bugs</a>:</td><td> </td><td align="left" valign="top"> 416</td></tr> 417</table> 418 419<a name="Running-the-Program-2"></a> 420<h4 class="subsection">1.2.1 Running the Program</h4> 421<p>The safest way to run the 422<code>ntp-keygen</code> 423program is logged in directly as root. 424The recommended procedure is change to the 425<kbd>keys</kbd> 426directory, usually 427<samp>/usr/local/etc</samp>, 428then run the program. 429</p> 430<p>To test and gain experience with Autokey concepts, log in as root and 431change to the 432<kbd>keys</kbd> 433directory, usually 434<samp>/usr/local/etc</samp>. 435When run for the first time, or if all files with names beginning with 436<samp>ntpkey*</samp> 437have been removed, use the 438<code>ntp-keygen</code> 439command without arguments to generate a default 440<code>RSA</code> 441host key and matching 442<code>RSA-MD5</code> 443certificate file with expiration date one year hence, 444which is all that is necessary in many cases. 445The program also generates soft links from the generic names 446to the respective files. 447If run again without options, the program uses the 448existing keys and parameters and generates a new certificate file with 449new expiration date one year hence, and soft link. 450</p> 451<p>The host key is used to encrypt the cookie when required and so must be 452<code>RSA</code> 453type. 454By default, the host key is also the sign key used to encrypt signatures. 455When necessary, a different sign key can be specified and this can be 456either 457<code>RSA</code> 458or 459<code>DSA</code> 460type. 461By default, the message digest type is 462<code>MD5</code>, 463but any combination 464of sign key type and message digest type supported by the OpenSSL library 465can be specified, including those using the 466<code>AES128CMAC</code>, <code>MD2</code>, <code>MD5</code>, <code>MDC2</code>, <code>SHA</code>, <code>SHA1</code> 467and 468<code>RIPE160</code> 469message digest algorithms. 470However, the scheme specified in the certificate must be compatible 471with the sign key. 472Certificates using any digest algorithm are compatible with 473<code>RSA</code> 474sign keys; 475however, only 476<code>SHA</code> 477and 478<code>SHA1</code> 479certificates are compatible with 480<code>DSA</code> 481sign keys. 482</p> 483<p>Private/public key files and certificates are compatible with 484other OpenSSL applications and very likely other libraries as well. 485Certificates or certificate requests derived from them should be compatible 486with extant industry practice, although some users might find 487the interpretation of X509v3 extension fields somewhat liberal. 488However, the identification parameter files, although encoded 489as the other files, are probably not compatible with anything other than Autokey. 490</p> 491<p>Running the program as other than root and using the Unix 492<code>su(1)</code> 493command 494to assume root may not work properly, since by default the OpenSSL library 495looks for the random seed file 496<samp>.rnd</samp> 497in the user home directory. 498However, there should be only one 499<samp>.rnd</samp>, 500most conveniently 501in the root directory, so it is convenient to define the 502.Ev RANDFILE 503environment variable used by the OpenSSL library as the path to 504<samp>.rnd</samp>. 505</p> 506<p>Installing the keys as root might not work in NFS-mounted 507shared file systems, as NFS clients may not be able to write 508to the shared keys directory, even as root. 509In this case, NFS clients can specify the files in another 510directory such as 511<samp>/etc</samp> 512using the 513<code>keysdir</code> 514<code>ntpd(1ntpdmdoc)</code> 515configuration file command. 516There is no need for one client to read the keys and certificates 517of other clients or servers, as these data are obtained automatically 518by the Autokey protocol. 519</p> 520<p>Ordinarily, cryptographic files are generated by the host that uses them, 521but it is possible for a trusted agent (TA) to generate these files 522for other hosts; however, in such cases files should always be encrypted. 523The subject name and trusted name default to the hostname 524of the host generating the files, but can be changed by command line options. 525It is convenient to designate the owner name and trusted name 526as the subject and issuer fields, respectively, of the certificate. 527The owner name is also used for the host and sign key files, 528while the trusted name is used for the identity files. 529</p> 530<p>All files are installed by default in the keys directory 531<samp>/usr/local/etc</samp>, 532which is normally in a shared filesystem 533in NFS-mounted networks. 534The actual location of the keys directory 535and each file can be overridden by configuration commands, 536but this is not recommended. 537Normally, the files for each host are generated by that host 538and used only by that host, although exceptions exist 539as noted later on this page. 540</p> 541<p>Normally, files containing private values, 542including the host key, sign key and identification parameters, 543are permitted root read/write-only; 544while others containing public values are permitted world readable. 545Alternatively, files containing private values can be encrypted 546and these files permitted world readable, 547which simplifies maintenance in shared file systems. 548Since uniqueness is insured by the 549<kbd>hostname</kbd> 550and 551<kbd>filestamp</kbd> 552file name extensions, the files for an NTP server and 553dependent clients can all be installed in the same shared directory. 554</p> 555<p>The recommended practice is to keep the file name extensions 556when installing a file and to install a soft link 557from the generic names specified elsewhere on this page 558to the generated files. 559This allows new file generations to be activated simply 560by changing the link. 561If a link is present, 562<code>ntpd(1ntpdmdoc)</code> 563follows it to the file name to extract the 564<kbd>filestamp</kbd>. 565If a link is not present, 566<code>ntpd(1ntpdmdoc)</code> 567extracts the 568<kbd>filestamp</kbd> 569from the file itself. 570This allows clients to verify that the file and generation times 571are always current. 572The 573<code>ntp-keygen</code> 574program uses the same 575<kbd>filestamp</kbd> 576extension for all files generated 577at one time, so each generation is distinct and can be readily 578recognized in monitoring data. 579</p> 580<p>Run the command on as many hosts as necessary. 581Designate one of them as the trusted host (TH) using 582<code>ntp-keygen</code> 583with the 584<code>-T</code> 585option and configure it to synchronize from reliable Internet servers. 586Then configure the other hosts to synchronize to the TH directly or 587indirectly. 588A certificate trail is created when Autokey asks the immediately 589ascendant host towards the TH to sign its certificate, which is then 590provided to the immediately descendant host on request. 591All group hosts should have acyclic certificate trails ending on the TH. 592</p> 593<p>The host key is used to encrypt the cookie when required and so must be 594RSA type. 595By default, the host key is also the sign key used to encrypt 596signatures. 597A different sign key can be assigned using the 598<code>-S</code> 599option and this can be either 600<code>RSA</code> 601or 602<code>DSA</code> 603type. 604By default, the signature 605message digest type is 606<code>MD5</code>, 607but any combination of sign key type and 608message digest type supported by the OpenSSL library can be specified 609using the 610<code>-c</code> 611option. 612</p> 613<p>The rules say cryptographic media should be generated with proventic 614filestamps, which means the host should already be synchronized before 615this program is run. 616This of course creates a chicken-and-egg problem 617when the host is started for the first time. 618Accordingly, the host time 619should be set by some other means, such as eyeball-and-wristwatch, at 620least so that the certificate lifetime is within the current year. 621After that and when the host is synchronized to a proventic source, the 622certificate should be re-generated. 623</p> 624<p>Additional information on trusted groups and identity schemes is on the 625“Autokey Public-Key Authentication” 626page. 627</p> 628<p>File names begin with the prefix 629<samp>ntpkey</samp>_ 630and end with the suffix 631<samp>_</samp><kbd>hostname</kbd>. <kbd>filestamp</kbd>, 632where 633<kbd>hostname</kbd> 634is the owner name, usually the string returned 635by the Unix 636<code>hostname(1)</code> 637command, and 638<kbd>filestamp</kbd> 639is the NTP seconds when the file was generated, in decimal digits. 640This both guarantees uniqueness and simplifies maintenance 641procedures, since all files can be quickly removed 642by a 643<code>rm</code> <samp>ntpkey*</samp> 644command or all files generated 645at a specific time can be removed by a 646<code>rm</code> <samp>*</samp><kbd>filestamp</kbd> 647command. 648To further reduce the risk of misconfiguration, 649the first two lines of a file contain the file name 650and generation date and time as comments. 651</p> 652<a name="Trusted-Hosts-and-Groups"></a> 653<h4 class="subsubsection">1.2.1.1 Trusted Hosts and Groups</h4> 654<p>Each cryptographic configuration involves selection of a signature scheme 655and identification scheme, called a cryptotype, 656as explained in the 657‘Authentication Options’ 658section of 659<code>ntp.conf(5)</code>. 660The default cryptotype uses 661<code>RSA</code> 662encryption, 663<code>MD5</code> 664message digest 665and 666<code>TC</code> 667identification. 668First, configure a NTP subnet including one or more low-stratum 669trusted hosts from which all other hosts derive synchronization 670directly or indirectly. 671Trusted hosts have trusted certificates; 672all other hosts have nontrusted certificates. 673These hosts will automatically and dynamically build authoritative 674certificate trails to one or more trusted hosts. 675A trusted group is the set of all hosts that have, directly or indirectly, 676a certificate trail ending at a trusted host. 677The trail is defined by static configuration file entries 678or dynamic means described on the 679‘Automatic NTP Configuration Options’ 680section of 681<code>ntp.conf(5)</code>. 682</p> 683<p>On each trusted host as root, change to the keys directory. 684To insure a fresh fileset, remove all 685<samp>ntpkey</samp> 686files. 687Then run 688<code>ntp-keygen</code> 689<code>-T</code> 690to generate keys and a trusted certificate. 691On all other hosts do the same, but leave off the 692<code>-T</code> 693flag to generate keys and nontrusted certificates. 694When complete, start the NTP daemons beginning at the lowest stratum 695and working up the tree. 696It may take some time for Autokey to instantiate the certificate trails 697throughout the subnet, but setting up the environment is completely automatic. 698</p> 699<p>If it is necessary to use a different sign key or different digest/signature 700scheme than the default, run 701<code>ntp-keygen</code> 702with the 703<code>-S</code> <kbd>type</kbd> 704option, where 705<kbd>type</kbd> 706is either 707<code>RSA</code> 708or 709<code>DSA</code>. 710The most frequent need to do this is when a 711<code>DSA</code>-signed 712certificate is used. 713If it is necessary to use a different certificate scheme than the default, 714run 715<code>ntp-keygen</code> 716with the 717<code>-c</code> <kbd>scheme</kbd> 718option and selected 719<kbd>scheme</kbd> 720as needed. 721If 722<code>ntp-keygen</code> 723is run again without these options, it generates a new certificate 724using the same scheme and sign key, and soft link. 725</p> 726<p>After setting up the environment it is advisable to update certificates 727from time to time, if only to extend the validity interval. 728Simply run 729<code>ntp-keygen</code> 730with the same flags as before to generate new certificates 731using existing keys, and soft links. 732However, if the host or sign key is changed, 733<code>ntpd(1ntpdmdoc)</code> 734should be restarted. 735When 736<code>ntpd(1ntpdmdoc)</code> 737is restarted, it loads any new files and restarts the protocol. 738Other dependent hosts will continue as usual until signatures are refreshed, 739at which time the protocol is restarted. 740</p> 741<a name="Identity-Schemes"></a> 742<h4 class="subsubsection">1.2.1.2 Identity Schemes</h4> 743<p>As mentioned on the Autonomous Authentication page, 744the default 745<code>TC</code> 746identity scheme is vulnerable to a middleman attack. 747However, there are more secure identity schemes available, 748including 749<code>PC</code>, <code>IFF</code>, <code>GQ</code> 750and 751<code>MV</code> 752schemes described below. 753These schemes are based on a TA, one or more trusted hosts 754and some number of nontrusted hosts. 755Trusted hosts prove identity using values provided by the TA, 756while the remaining hosts prove identity using values provided 757by a trusted host and certificate trails that end on that host. 758The name of a trusted host is also the name of its sugroup 759and also the subject and issuer name on its trusted certificate. 760The TA is not necessarily a trusted host in this sense, but often is. 761</p> 762<p>In some schemes there are separate keys for servers and clients. 763A server can also be a client of another server, 764but a client can never be a server for another client. 765In general, trusted hosts and nontrusted hosts that operate 766as both server and client have parameter files that contain 767both server and client keys. 768Hosts that operate 769only as clients have key files that contain only client keys. 770</p> 771<p>The PC scheme supports only one trusted host in the group. 772On trusted host alice run 773<code>ntp-keygen</code> 774<code>-P</code> 775<code>-p</code> <kbd>password</kbd> 776to generate the host key file 777<samp>ntpkey</samp>_ <code>RSA</code> <samp>key_alice.</samp> <kbd>filestamp</kbd> 778and trusted private certificate file 779<samp>ntpkey</samp>_ <code>RSA-MD5</code> <code>_</code> <samp>cert_alice.</samp> <kbd>filestamp</kbd>, 780and soft links. 781Copy both files to all group hosts; 782they replace the files which would be generated in other schemes. 783On each host 784<kbd>bob</kbd> 785install a soft link from the generic name 786<samp>ntpkey_host_</samp><kbd>bob</kbd> 787to the host key file and soft link 788<samp>ntpkey_cert_</samp><kbd>bob</kbd> 789to the private certificate file. 790Note the generic links are on bob, but point to files generated 791by trusted host alice. 792In this scheme it is not possible to refresh 793either the keys or certificates without copying them 794to all other hosts in the group, and recreating the soft links. 795</p> 796<p>For the 797<code>IFF</code> 798scheme proceed as in the 799<code>TC</code> 800scheme to generate keys 801and certificates for all group hosts, then for every trusted host in the group, 802generate the 803<code>IFF</code> 804parameter file. 805On trusted host alice run 806<code>ntp-keygen</code> 807<code>-T</code> 808<code>-I</code> 809<code>-p</code> <kbd>password</kbd> 810to produce her parameter file 811<samp>ntpkey_IFFpar_alice.</samp><kbd>filestamp</kbd>, 812which includes both server and client keys. 813Copy this file to all group hosts that operate as both servers 814and clients and install a soft link from the generic 815<samp>ntpkey_iff_alice</samp> 816to this file. 817If there are no hosts restricted to operate only as clients, 818there is nothing further to do. 819As the 820<code>IFF</code> 821scheme is independent 822of keys and certificates, these files can be refreshed as needed. 823</p> 824<p>If a rogue client has the parameter file, it could masquerade 825as a legitimate server and present a middleman threat. 826To eliminate this threat, the client keys can be extracted 827from the parameter file and distributed to all restricted clients. 828After generating the parameter file, on alice run 829<code>ntp-keygen</code> 830<code>-e</code> 831and pipe the output to a file or email program. 832Copy or email this file to all restricted clients. 833On these clients install a soft link from the generic 834<samp>ntpkey_iff_alice</samp> 835to this file. 836To further protect the integrity of the keys, 837each file can be encrypted with a secret password. 838</p> 839<p>For the 840<code>GQ</code> 841scheme proceed as in the 842<code>TC</code> 843scheme to generate keys 844and certificates for all group hosts, then for every trusted host 845in the group, generate the 846<code>IFF</code> 847parameter file. 848On trusted host alice run 849<code>ntp-keygen</code> 850<code>-T</code> 851<code>-G</code> 852<code>-p</code> <kbd>password</kbd> 853to produce her parameter file 854<samp>ntpkey_GQpar_alice.</samp><kbd>filestamp</kbd>, 855which includes both server and client keys. 856Copy this file to all group hosts and install a soft link 857from the generic 858<samp>ntpkey_gq_alice</samp> 859to this file. 860In addition, on each host 861<kbd>bob</kbd> 862install a soft link 863from generic 864<samp>ntpkey_gq_</samp><kbd>bob</kbd> 865to this file. 866As the 867<code>GQ</code> 868scheme updates the 869<code>GQ</code> 870parameters file and certificate 871at the same time, keys and certificates can be regenerated as needed. 872</p> 873<p>For the 874<code>MV</code> 875scheme, proceed as in the 876<code>TC</code> 877scheme to generate keys 878and certificates for all group hosts. 879For illustration assume trish is the TA, alice one of several trusted hosts 880and bob one of her clients. 881On TA trish run 882<code>ntp-keygen</code> 883<code>-V</code> <kbd>n</kbd> 884<code>-p</code> <kbd>password</kbd>, 885where 886<kbd>n</kbd> 887is the number of revokable keys (typically 5) to produce 888the parameter file 889<samp>ntpkeys_MVpar_trish.</samp><kbd>filestamp</kbd> 890and client key files 891<samp>ntpkeys_MVkey</samp><kbd>d</kbd> <kbd>_</kbd> <samp>trish.</samp> <kbd>filestamp</kbd> 892where 893<kbd>d</kbd> 894is the key number (0 < 895<kbd>d</kbd> 896< 897<kbd>n</kbd>). 898Copy the parameter file to alice and install a soft link 899from the generic 900<samp>ntpkey_mv_alice</samp> 901to this file. 902Copy one of the client key files to alice for later distribution 903to her clients. 904It does not matter which client key file goes to alice, 905since they all work the same way. 906Alice copies the client key file to all of her clients. 907On client bob install a soft link from generic 908<samp>ntpkey_mvkey_bob</samp> 909to the client key file. 910As the 911<code>MV</code> 912scheme is independent of keys and certificates, 913these files can be refreshed as needed. 914</p> 915<a name="Command-Line-Options"></a> 916<h4 class="subsubsection">1.2.1.3 Command Line Options</h4> 917<dl compact="compact"> 918<dt><code>-b</code> <code>--imbits</code>= <kbd>modulus</kbd></dt> 919<dd><p>Set the number of bits in the identity modulus for generating identity keys to 920<kbd>modulus</kbd> 921bits. 922The number of bits in the identity modulus defaults to 256, but can be set to 923values from 256 to 2048 (32 to 256 octets). 924Use the larger moduli with caution, as this can consume considerable computing 925resources and increases the size of authenticated packets. 926</p></dd> 927<dt><code>-c</code> <code>--certificate</code>= <kbd>scheme</kbd></dt> 928<dd><p>Select certificate signature encryption/message digest scheme. 929The 930<kbd>scheme</kbd> 931can be one of the following: 932<code>RSA-MD2</code>, <code>RSA-MD5</code>, <code>RSA-MDC2</code>, <code>RSA-SHA</code>, <code>RSA-SHA1</code>, <code>RSA-RIPEMD160</code>, <code>DSA-SHA</code>, 933or 934<code>DSA-SHA1</code>. 935Note that 936<code>RSA</code> 937schemes must be used with an 938<code>RSA</code> 939sign key and 940<code>DSA</code> 941schemes must be used with a 942<code>DSA</code> 943sign key. 944The default without this option is 945<code>RSA-MD5</code>. 946If compatibility with FIPS 140-2 is required, either the 947<code>DSA-SHA</code> 948or 949<code>DSA-SHA1</code> 950scheme must be used. 951</p></dd> 952<dt><code>-C</code> <code>--cipher</code>= <kbd>cipher</kbd></dt> 953<dd><p>Select the OpenSSL cipher to encrypt the files containing private keys. 954The default without this option is three-key triple DES in CBC mode, 955<code>des-ede3-cbc</code>. 956The 957<code>openssl</code> <code>-h</code> 958command provided with OpenSSL displays available ciphers. 959</p></dd> 960<dt><code>-d</code> <code>--debug-level</code></dt> 961<dd><p>Increase debugging verbosity level. 962This option displays the cryptographic data produced in eye-friendly billboards. 963</p></dd> 964<dt><code>-D</code> <code>--set-debug-level</code>= <kbd>level</kbd></dt> 965<dd><p>Set the debugging verbosity to 966<kbd>level</kbd>. 967This option displays the cryptographic data produced in eye-friendly billboards. 968</p></dd> 969<dt><code>-e</code> <code>--id-key</code></dt> 970<dd><p>Write the 971<code>IFF</code> 972or 973<code>GQ</code> 974public parameters from the 975<kbd>IFFkey</kbd> <kbd>or</kbd> <kbd>GQkey</kbd> 976client keys file previously specified 977as unencrypted data to the standard output stream 978<samp>stdout</samp>. 979This is intended for automatic key distribution by email. 980</p></dd> 981<dt><code>-G</code> <code>--gq-params</code></dt> 982<dd><p>Generate a new encrypted 983<code>GQ</code> 984parameters and key file for the Guillou-Quisquater (GQ) identity scheme. 985This option is mutually exclusive with the 986<code>-I</code> 987and 988<code>-V</code> 989options. 990</p></dd> 991<dt><code>-H</code> <code>--host-key</code></dt> 992<dd><p>Generate a new encrypted 993<code>RSA</code> 994public/private host key file. 995</p></dd> 996<dt><code>-I</code> <code>--iffkey</code></dt> 997<dd><p>Generate a new encrypted 998<code>IFF</code> 999key file for the Schnorr (IFF) identity scheme. 1000This option is mutually exclusive with the 1001<code>-G</code> 1002and 1003Fl V 1004options. 1005</p></dd> 1006<dt><code>-i</code> <code>--ident</code>= <kbd>group</kbd></dt> 1007<dd><p>Set the optional Autokey group name to 1008<kbd>group</kbd>. 1009This is used in the identity scheme parameter file names of 1010<code>IFF</code>, <code>GQ</code>, 1011and 1012<code>MV</code> 1013client parameters files. 1014In that role, the default is the host name if no group is provided. 1015The group name, if specified using 1016<code>-i</code> 1017or 1018<code>-s</code> 1019following an 1020‘@’ 1021character, is also used in certificate subject and issuer names in the form 1022<kbd>host</kbd> <kbd>@</kbd> <kbd>group</kbd> 1023and should match the group specified via 1024<code>crypto</code> <code>ident</code> 1025or 1026<code>server</code> <code>ident</code> 1027in the ntpd configuration file. 1028</p></dd> 1029<dt><code>-l</code> <code>--lifetime</code>= <kbd>days</kbd></dt> 1030<dd><p>Set the lifetime for certificate expiration to 1031<kbd>days</kbd>. 1032The default lifetime is one year (365 days). 1033</p></dd> 1034<dt><code>-m</code> <code>--modulus</code>= <kbd>bits</kbd></dt> 1035<dd><p>Set the number of bits in the prime modulus for generating files to 1036<kbd>bits</kbd>. 1037The modulus defaults to 512, but can be set from 256 to 2048 (32 to 256 octets). 1038Use the larger moduli with caution, as this can consume considerable computing 1039resources and increases the size of authenticated packets. 1040</p></dd> 1041<dt><code>-M</code> <code>--md5key</code></dt> 1042<dd><p>Generate a new symmetric keys file containing 10 1043<code>MD5</code> 1044keys, and if OpenSSL is available, 10 1045<code>SHA</code> 1046keys. 1047An 1048<code>MD5</code> 1049key is a string of 20 random printable ASCII characters, while a 1050<code>SHA</code> 1051key is a string of 40 random hex digits. 1052The file can be edited using a text editor to change the key type or key content. 1053This option is mutually exclusive with all other options. 1054</p></dd> 1055<dt><code>-p</code> <code>--password</code>= <kbd>passwd</kbd></dt> 1056<dd><p>Set the password for reading and writing encrypted files to 1057<kbd>passwd</kbd>. 1058These include the host, sign and identify key files. 1059By default, the password is the string returned by the Unix 1060<code>hostname</code> 1061command. 1062</p></dd> 1063<dt><code>-P</code> <code>--pvt-cert</code></dt> 1064<dd><p>Generate a new private certificate used by the 1065<code>PC</code> 1066identity scheme. 1067By default, the program generates public certificates. 1068Note: the PC identity scheme is not recommended for new installations. 1069</p></dd> 1070<dt><code>-q</code> <code>--export-passwd</code>= <kbd>passwd</kbd></dt> 1071<dd><p>Set the password for writing encrypted 1072<code>IFF</code>, <code>GQ</code> <code>and</code> <code>MV</code> 1073identity files redirected to 1074<samp>stdout</samp> 1075to 1076<kbd>passwd</kbd>. 1077In effect, these files are decrypted with the 1078<code>-p</code> 1079password, then encrypted with the 1080<code>-q</code> 1081password. 1082By default, the password is the string returned by the Unix 1083<code>hostname</code> 1084command. 1085</p></dd> 1086<dt><code>-s</code> <code>--subject-key</code>= <code>[host]</code> <code>[@ <kbd>group</kbd>]</code></dt> 1087<dd><p>Specify the Autokey host name, where 1088<kbd>host</kbd> 1089is the optional host name and 1090<kbd>group</kbd> 1091is the optional group name. 1092The host name, and if provided, group name are used in 1093<kbd>host</kbd> <kbd>@</kbd> <kbd>group</kbd> 1094form as certificate subject and issuer. 1095Specifying 1096<code>-s</code> <code>-@</code> <kbd>group</kbd> 1097is allowed, and results in leaving the host name unchanged, as with 1098<code>-i</code> <kbd>group</kbd>. 1099The group name, or if no group is provided, the host name are also used in the 1100file names of 1101<code>IFF</code>, <code>GQ</code>, 1102and 1103<code>MV</code> 1104identity scheme client parameter files. 1105If 1106<kbd>host</kbd> 1107is not specified, the default host name is the string returned by the Unix 1108<code>hostname</code> 1109command. 1110</p></dd> 1111<dt><code>-S</code> <code>--sign-key</code>= <code>[<code>RSA</code> | <code>DSA</code>]</code></dt> 1112<dd><p>Generate a new encrypted public/private sign key file of the specified type. 1113By default, the sign key is the host key and has the same type. 1114If compatibility with FIPS 140-2 is required, the sign key type must be 1115<code>DSA</code>. 1116</p></dd> 1117<dt><code>-T</code> <code>--trusted-cert</code></dt> 1118<dd><p>Generate a trusted certificate. 1119By default, the program generates a non-trusted certificate. 1120</p></dd> 1121<dt><code>-V</code> <code>--mv-params</code> <kbd>nkeys</kbd></dt> 1122<dd><p>Generate 1123<kbd>nkeys</kbd> 1124encrypted server keys and parameters for the Mu-Varadharajan (MV) 1125identity scheme. 1126This option is mutually exclusive with the 1127<code>-I</code> 1128and 1129<code>-G</code> 1130options. 1131Note: support for this option should be considered a work in progress. 1132</p></dd> 1133</dl> 1134 1135<a name="Random-Seed-File-1"></a> 1136<h4 class="subsubsection">1.2.1.4 Random Seed File</h4> 1137<p>All cryptographically sound key generation schemes must have means 1138to randomize the entropy seed used to initialize 1139the internal pseudo-random number generator used 1140by the library routines. 1141The OpenSSL library uses a designated random seed file for this purpose. 1142The file must be available when starting the NTP daemon and 1143<code>ntp-keygen</code> 1144program. 1145If a site supports OpenSSL or its companion OpenSSH, 1146it is very likely that means to do this are already available. 1147</p> 1148<p>It is important to understand that entropy must be evolved 1149for each generation, for otherwise the random number sequence 1150would be predictable. 1151Various means dependent on external events, such as keystroke intervals, 1152can be used to do this and some systems have built-in entropy sources. 1153Suitable means are described in the OpenSSL software documentation, 1154but are outside the scope of this page. 1155</p> 1156<p>The entropy seed used by the OpenSSL library is contained in a file, 1157usually called 1158<samp>.rnd</samp>, 1159which must be available when starting the NTP daemon 1160or the 1161<code>ntp-keygen</code> 1162program. 1163The NTP daemon will first look for the file 1164using the path specified by the 1165<code>randfile</code> 1166subcommand of the 1167<code>crypto</code> 1168configuration command. 1169If not specified in this way, or when starting the 1170<code>ntp-keygen</code> 1171program, 1172the OpenSSL library will look for the file using the path specified 1173by the 1174.Ev RANDFILE 1175environment variable in the user home directory, 1176whether root or some other user. 1177If the 1178.Ev RANDFILE 1179environment variable is not present, 1180the library will look for the 1181<samp>.rnd</samp> 1182file in the user home directory. 1183Since both the 1184<code>ntp-keygen</code> 1185program and 1186<code>ntpd(1ntpdmdoc)</code> 1187daemon must run as root, the logical place to put this file is in 1188<samp>/.rnd</samp> 1189or 1190<samp>/root/.rnd</samp>. 1191If the file is not available or cannot be written, 1192the daemon exits with a message to the system log and the program 1193exits with a suitable error message. 1194</p> 1195<a name="Cryptographic-Data-Files-1"></a> 1196<h4 class="subsubsection">1.2.1.5 Cryptographic Data Files</h4> 1197<p>All file formats begin with two nonencrypted lines. 1198The first line contains the file name, including the generated host name 1199and filestamp, in the format 1200<samp>ntpkey_</samp><kbd>key</kbd> <kbd>_</kbd> <kbd>name</kbd>. <kbd>filestamp</kbd>, 1201where 1202<kbd>key</kbd> 1203is the key or parameter type, 1204<kbd>name</kbd> 1205is the host or group name and 1206<kbd>filestamp</kbd> 1207is the filestamp (NTP seconds) when the file was created. 1208By convention, 1209<kbd>key</kbd> 1210names in generated file names include both upper and lower case 1211characters, while 1212<kbd>key</kbd> 1213names in generated link names include only lower case characters. 1214The filestamp is not used in generated link names. 1215The second line contains the datestamp in conventional Unix 1216<samp>date</samp> 1217format. 1218Lines beginning with 1219‘#’ 1220are considered comments and ignored by the 1221<code>ntp-keygen</code> 1222program and 1223<code>ntpd(1ntpdmdoc)</code> 1224daemon. 1225</p> 1226<p>The remainder of the file contains cryptographic data, encoded first using ASN.1 1227rules, then encrypted if necessary, and finally written in PEM-encoded 1228printable ASCII text, preceded and followed by MIME content identifier lines. 1229</p> 1230<p>The format of the symmetric keys file, ordinarily named 1231<samp>ntp.keys</samp>, 1232is somewhat different than the other files in the interest of backward compatibility. 1233Ordinarily, the file is generated by this program, but it can be constructed 1234and edited using an ordinary text editor. 1235</p><pre class="verbatim"># ntpkey_MD5key_bk.ntp.org.3595864945 1236# Thu Dec 12 19:22:25 2013 1237 12381 MD5 L";Nw<\`.I<f4U0)247"i # MD5 key 12392 MD5 &>l0%XXK9O'51VwV<xq~ # MD5 key 12403 MD5 lb4zLW~d^!K:]RsD'qb6 # MD5 key 12414 MD5 Yue:tL[+vR)M\`n~bY,'? # MD5 key 12425 MD5 B;fx'Kgr/&4ZTbL6=RxA # MD5 key 12436 MD5 4eYwa\`o@}3i@@@@V@@..R9!l # MD5 key 12447 MD5 \`A.([h+;wTQ|xfi%Sn_! # MD5 key 12458 MD5 45:V,r4]l6y^JH6"Sh?F # MD5 key 12469 MD5 3-5vcn*6l29DS?Xdsg)* # MD5 key 124710 MD5 2late4Me # MD5 key 124811 SHA1 a27872d3030a9025b8446c751b4551a7629af65c # SHA1 key 124912 SHA1 21bc3b4865dbb9e920902abdccb3e04ff97a5e74 # SHA1 key 125013 SHA1 2b7736fe24fef5ba85ae11594132ab5d6f6daba9 # SHA1 key 125114 SHA a5332809c8878dd3a5b918819108a111509aeceb # SHA key 125215 MD2 2fe16c88c760ff2f16d4267e36c1aa6c926e6964 # MD2 key 125316 MD4 b2691811dc19cfc0e2f9bcacd74213f29812183d # MD4 key 125417 MD5 e4d6735b8bdad58ec5ffcb087300a17f7fef1f7c # MD5 key 125518 MDC2 a8d5e2315c025bf3a79174c87fbd10477de2eabc # MDC2 key 125619 RIPEMD160 77ca332cafb30e3cafb174dcd5b80ded7ba9b3d2 # RIPEMD160 key 125720 AES128CMAC f92ff73eee86c1e7dc638d6489a04e4e555af878 # AES128CMAC key 1258</pre><div class="example"> 1259<pre class="example">Figure 1. Typical Symmetric Key File 1260</pre></div> 1261 1262<p>Figure 1 shows a typical symmetric keys file used by the reference 1263implementation. 1264Following the header the keys are entered one per line in the format 1265</p><div class="example"> 1266<pre class="example"><kbd>keyno</kbd> <kbd>type</kbd> <kbd>key</kbd> 1267</pre></div> 1268<p>where 1269<kbd>keyno</kbd> 1270is a positive integer in the range 1-65535; 1271<kbd>type</kbd> 1272is the key type for the message digest algorithm, which in the absence of the 1273OpenSSL library must be 1274<code>MD5</code> 1275to designate the MD5 message digest algorithm; 1276if the OpenSSL library is installed, the key type can be any 1277message digest algorithm supported by that library; 1278however, if compatibility with FIPS 140-2 is required, 1279the key type must be either 1280<code>SHA</code> 1281or 1282<code>SHA1</code>; 1283<kbd>key</kbd> 1284is the key itself, 1285which is a printable ASCII string 20 characters or less in length: 1286each character is chosen from the 93 printable characters 1287in the range 0x21 through 0x7e ( 1288‘’! 1289through 1290‘~’ 1291) excluding space and the 1292‘#’ 1293character, and terminated by whitespace or a 1294‘#’ 1295character. 1296An OpenSSL key consists of a hex-encoded ASCII string of 40 characters, which 1297is truncated as necessary. 1298</p> 1299<p>Note that the keys used by the 1300<code>ntpq(1ntpqmdoc)</code> 1301and 1302<code>ntpdc(1ntpdcmdoc)</code> 1303programs 1304are checked against passwords requested by the programs 1305and entered by hand, so it is generally appropriate to specify these keys 1306in human readable ASCII format. 1307</p> 1308<p>The 1309<code>ntp-keygen</code> 1310program generates a symmetric keys file 1311<samp>ntpkey_MD5key_</samp><kbd>hostname</kbd>. <kbd>filestamp</kbd>. 1312Since the file contains private shared keys, 1313it should be visible only to root and distributed by secure means 1314to other subnet hosts. 1315The NTP daemon loads the file 1316<samp>ntp.keys</samp>, 1317so 1318<code>ntp-keygen</code> 1319installs a soft link from this name to the generated file. 1320Subsequently, similar soft links must be installed by manual 1321or automated means on the other subnet hosts. 1322While this file is not used with the Autokey Version 2 protocol, 1323it is needed to authenticate some remote configuration commands 1324used by the 1325<code>ntpq(1ntpqmdoc)</code> 1326and 1327<code>ntpdc(1ntpdcmdoc)</code> 1328utilities. 1329</p> 1330<p>This section was generated by <strong>AutoGen</strong>, 1331using the <code>agtexi-cmd</code> template and the option descriptions for the <code>ntp-keygen</code> program. 1332This software is released under the NTP license, <http://ntp.org/license>;. 1333</p> 1334<table class="menu" border="0" cellspacing="0"> 1335<tr><td align="left" valign="top">• <a href="#ntp_002dkeygen-usage" accesskey="1">ntp-keygen usage</a>:</td><td> </td><td align="left" valign="top">ntp-keygen help/usage (<samp>--help</samp>) 1336</td></tr> 1337<tr><td align="left" valign="top">• <a href="#ntp_002dkeygen-imbits" accesskey="2">ntp-keygen imbits</a>:</td><td> </td><td align="left" valign="top">imbits option (-b) 1338</td></tr> 1339<tr><td align="left" valign="top">• <a href="#ntp_002dkeygen-certificate" accesskey="3">ntp-keygen certificate</a>:</td><td> </td><td align="left" valign="top">certificate option (-c) 1340</td></tr> 1341<tr><td align="left" valign="top">• <a href="#ntp_002dkeygen-cipher" accesskey="4">ntp-keygen cipher</a>:</td><td> </td><td align="left" valign="top">cipher option (-C) 1342</td></tr> 1343<tr><td align="left" valign="top">• <a href="#ntp_002dkeygen-id_002dkey" accesskey="5">ntp-keygen id-key</a>:</td><td> </td><td align="left" valign="top">id-key option (-e) 1344</td></tr> 1345<tr><td align="left" valign="top">• <a href="#ntp_002dkeygen-gq_002dparams" accesskey="6">ntp-keygen gq-params</a>:</td><td> </td><td align="left" valign="top">gq-params option (-G) 1346</td></tr> 1347<tr><td align="left" valign="top">• <a href="#ntp_002dkeygen-host_002dkey" accesskey="7">ntp-keygen host-key</a>:</td><td> </td><td align="left" valign="top">host-key option (-H) 1348</td></tr> 1349<tr><td align="left" valign="top">• <a href="#ntp_002dkeygen-iffkey" accesskey="8">ntp-keygen iffkey</a>:</td><td> </td><td align="left" valign="top">iffkey option (-I) 1350</td></tr> 1351<tr><td align="left" valign="top">• <a href="#ntp_002dkeygen-ident" accesskey="9">ntp-keygen ident</a>:</td><td> </td><td align="left" valign="top">ident option (-i) 1352</td></tr> 1353<tr><td align="left" valign="top">• <a href="#ntp_002dkeygen-lifetime">ntp-keygen lifetime</a>:</td><td> </td><td align="left" valign="top">lifetime option (-l) 1354</td></tr> 1355<tr><td align="left" valign="top">• <a href="#ntp_002dkeygen-modulus">ntp-keygen modulus</a>:</td><td> </td><td align="left" valign="top">modulus option (-m) 1356</td></tr> 1357<tr><td align="left" valign="top">• <a href="#ntp_002dkeygen-md5key">ntp-keygen md5key</a>:</td><td> </td><td align="left" valign="top">md5key option (-M) 1358</td></tr> 1359<tr><td align="left" valign="top">• <a href="#ntp_002dkeygen-pvt_002dcert">ntp-keygen pvt-cert</a>:</td><td> </td><td align="left" valign="top">pvt-cert option (-P) 1360</td></tr> 1361<tr><td align="left" valign="top">• <a href="#ntp_002dkeygen-password">ntp-keygen password</a>:</td><td> </td><td align="left" valign="top">password option (-p) 1362</td></tr> 1363<tr><td align="left" valign="top">• <a href="#ntp_002dkeygen-export_002dpasswd">ntp-keygen export-passwd</a>:</td><td> </td><td align="left" valign="top">export-passwd option (-q) 1364</td></tr> 1365<tr><td align="left" valign="top">• <a href="#ntp_002dkeygen-subject_002dname">ntp-keygen subject-name</a>:</td><td> </td><td align="left" valign="top">subject-name option (-s) 1366</td></tr> 1367<tr><td align="left" valign="top">• <a href="#ntp_002dkeygen-sign_002dkey">ntp-keygen sign-key</a>:</td><td> </td><td align="left" valign="top">sign-key option (-S) 1368</td></tr> 1369<tr><td align="left" valign="top">• <a href="#ntp_002dkeygen-trusted_002dcert">ntp-keygen trusted-cert</a>:</td><td> </td><td align="left" valign="top">trusted-cert option (-T) 1370</td></tr> 1371<tr><td align="left" valign="top">• <a href="#ntp_002dkeygen-mv_002dparams">ntp-keygen mv-params</a>:</td><td> </td><td align="left" valign="top">mv-params option (-V) 1372</td></tr> 1373<tr><td align="left" valign="top">• <a href="#ntp_002dkeygen-mv_002dkeys">ntp-keygen mv-keys</a>:</td><td> </td><td align="left" valign="top">mv-keys option (-v) 1374</td></tr> 1375<tr><td align="left" valign="top">• <a href="#ntp_002dkeygen-config">ntp-keygen config</a>:</td><td> </td><td align="left" valign="top">presetting/configuring ntp-keygen 1376</td></tr> 1377<tr><td align="left" valign="top">• <a href="#ntp_002dkeygen-exit-status">ntp-keygen exit status</a>:</td><td> </td><td align="left" valign="top">exit status 1378</td></tr> 1379<tr><td align="left" valign="top">• <a href="#ntp_002dkeygen-Usage">ntp-keygen Usage</a>:</td><td> </td><td align="left" valign="top">Usage 1380</td></tr> 1381<tr><td align="left" valign="top">• <a href="#ntp_002dkeygen-Notes">ntp-keygen Notes</a>:</td><td> </td><td align="left" valign="top">Notes 1382</td></tr> 1383<tr><td align="left" valign="top">• <a href="#ntp_002dkeygen-Bugs">ntp-keygen Bugs</a>:</td><td> </td><td align="left" valign="top">Bugs 1384</td></tr> 1385</table> 1386 1387<hr> 1388<a name="ntp_002dkeygen-usage"></a> 1389<div class="header"> 1390<p> 1391Next: <a href="#ntp_002dkeygen-imbits" accesskey="n" rel="next">ntp-keygen imbits</a>, Up: <a href="#ntp_002dkeygen-Invocation" accesskey="u" rel="up">ntp-keygen Invocation</a> </p> 1392</div> 1393<a name="ntp_002dkeygen-help_002fusage-_0028_002d_002dhelp_0029"></a> 1394<h4 class="subsection">1.2.2 ntp-keygen help/usage (<samp>--help</samp>)</h4> 1395<a name="index-ntp_002dkeygen-help"></a> 1396 1397<p>This is the automatically generated usage text for ntp-keygen. 1398</p> 1399<p>The text printed is the same whether selected with the <code>help</code> option 1400(<samp>--help</samp>) or the <code>more-help</code> option (<samp>--more-help</samp>). <code>more-help</code> will print 1401the usage text by passing it through a pager program. 1402<code>more-help</code> is disabled on platforms without a working 1403<code>fork(2)</code> function. The <code>PAGER</code> environment variable is 1404used to select the program, defaulting to <samp>more</samp>. Both will exit 1405with a status code of 0. 1406</p> 1407<div class="example"> 1408<pre class="example">ntp-keygen (ntp) - Create a NTP host key - Ver. 4.2.8p12 1409Usage: ntp-keygen [ -<flag> [<val>] | --<name>[{=| }<val>] ]... 1410 Flg Arg Option-Name Description 1411 -b Num imbits identity modulus bits 1412 - it must be in the range: 1413 256 to 2048 1414 -c Str certificate certificate scheme 1415 -C Str cipher privatekey cipher 1416 -d no debug-level Increase debug verbosity level 1417 - may appear multiple times 1418 -D Num set-debug-level Set the debug verbosity level 1419 - may appear multiple times 1420 -e no id-key Write IFF or GQ identity keys 1421 -G no gq-params Generate GQ parameters and keys 1422 -H no host-key generate RSA host key 1423 -I no iffkey generate IFF parameters 1424 -i Str ident set Autokey group name 1425 -l Num lifetime set certificate lifetime 1426 -m Num modulus prime modulus 1427 - it must be in the range: 1428 256 to 2048 1429 -M no md5key generate symmetric keys 1430 -P no pvt-cert generate PC private certificate 1431 -p Str password local private password 1432 -q Str export-passwd export IFF or GQ group keys with password 1433 -s Str subject-name set host and optionally group name 1434 -S Str sign-key generate sign key (RSA or DSA) 1435 -T no trusted-cert trusted certificate (TC scheme) 1436 -V Num mv-params generate <num> MV parameters 1437 -v Num mv-keys update <num> MV keys 1438 opt version output version information and exit 1439 -? no help display extended usage information and exit 1440 -! no more-help extended usage information passed thru pager 1441 -> opt save-opts save the option state to a config file 1442 -< Str load-opts load options from a config file 1443 - disabled as '--no-load-opts' 1444 - may appear multiple times 1445 1446Options are specified by doubled hyphens and their name or by a single 1447hyphen and the flag character. 1448 1449 1450The following option preset mechanisms are supported: 1451 - reading file $HOME/.ntprc 1452 - reading file ./.ntprc 1453 - examining environment variables named NTP_KEYGEN_* 1454 1455Please send bug reports to: <http://bugs.ntp.org, bugs@ntp.org> 1456</pre></div> 1457 1458<hr> 1459<a name="ntp_002dkeygen-imbits"></a> 1460<div class="header"> 1461<p> 1462Next: <a href="#ntp_002dkeygen-certificate" accesskey="n" rel="next">ntp-keygen certificate</a>, Previous: <a href="#ntp_002dkeygen-usage" accesskey="p" rel="prev">ntp-keygen usage</a>, Up: <a href="#ntp_002dkeygen-Invocation" accesskey="u" rel="up">ntp-keygen Invocation</a> </p> 1463</div> 1464<a name="imbits-option-_0028_002db_0029"></a> 1465<h4 class="subsection">1.2.3 imbits option (-b)</h4> 1466<a name="index-ntp_002dkeygen_002dimbits"></a> 1467 1468<p>This is the “identity modulus bits” option. 1469This option takes a number argument <samp>imbits</samp>. 1470</p> 1471<p>This option has some usage constraints. It: 1472</p><ul> 1473<li> must be compiled in by defining <code>AUTOKEY</code> during the compilation. 1474</li></ul> 1475 1476<p>The number of bits in the identity modulus. The default is 256. 1477</p><hr> 1478<a name="ntp_002dkeygen-certificate"></a> 1479<div class="header"> 1480<p> 1481Next: <a href="#ntp_002dkeygen-cipher" accesskey="n" rel="next">ntp-keygen cipher</a>, Previous: <a href="#ntp_002dkeygen-imbits" accesskey="p" rel="prev">ntp-keygen imbits</a>, Up: <a href="#ntp_002dkeygen-Invocation" accesskey="u" rel="up">ntp-keygen Invocation</a> </p> 1482</div> 1483<a name="certificate-option-_0028_002dc_0029"></a> 1484<h4 class="subsection">1.2.4 certificate option (-c)</h4> 1485<a name="index-ntp_002dkeygen_002dcertificate"></a> 1486 1487<p>This is the “certificate scheme” option. 1488This option takes a string argument <samp>scheme</samp>. 1489</p> 1490<p>This option has some usage constraints. It: 1491</p><ul> 1492<li> must be compiled in by defining <code>AUTOKEY</code> during the compilation. 1493</li></ul> 1494 1495<p>scheme is one of 1496RSA-MD2, RSA-MD5, RSA-MDC2, RSA-SHA, RSA-SHA1, RSA-RIPEMD160, 1497DSA-SHA, or DSA-SHA1. 1498</p> 1499<p>Select the certificate signature encryption/message digest scheme. 1500Note that RSA schemes must be used with a RSA sign key and DSA 1501schemes must be used with a DSA sign key. The default without 1502this option is RSA-MD5. 1503</p><hr> 1504<a name="ntp_002dkeygen-cipher"></a> 1505<div class="header"> 1506<p> 1507Next: <a href="#ntp_002dkeygen-id_002dkey" accesskey="n" rel="next">ntp-keygen id-key</a>, Previous: <a href="#ntp_002dkeygen-certificate" accesskey="p" rel="prev">ntp-keygen certificate</a>, Up: <a href="#ntp_002dkeygen-Invocation" accesskey="u" rel="up">ntp-keygen Invocation</a> </p> 1508</div> 1509<a name="cipher-option-_0028_002dC_0029"></a> 1510<h4 class="subsection">1.2.5 cipher option (-C)</h4> 1511<a name="index-ntp_002dkeygen_002dcipher"></a> 1512 1513<p>This is the “privatekey cipher” option. 1514This option takes a string argument <samp>cipher</samp>. 1515</p> 1516<p>This option has some usage constraints. It: 1517</p><ul> 1518<li> must be compiled in by defining <code>AUTOKEY</code> during the compilation. 1519</li></ul> 1520 1521<p>Select the cipher which is used to encrypt the files containing 1522private keys. The default is three-key triple DES in CBC mode, 1523equivalent to "<code>-C des-ede3-cbc</code>". The openssl tool lists ciphers 1524available in "<code>openssl -h</code>" output. 1525</p><hr> 1526<a name="ntp_002dkeygen-id_002dkey"></a> 1527<div class="header"> 1528<p> 1529Next: <a href="#ntp_002dkeygen-gq_002dparams" accesskey="n" rel="next">ntp-keygen gq-params</a>, Previous: <a href="#ntp_002dkeygen-cipher" accesskey="p" rel="prev">ntp-keygen cipher</a>, Up: <a href="#ntp_002dkeygen-Invocation" accesskey="u" rel="up">ntp-keygen Invocation</a> </p> 1530</div> 1531<a name="id_002dkey-option-_0028_002de_0029"></a> 1532<h4 class="subsection">1.2.6 id-key option (-e)</h4> 1533<a name="index-ntp_002dkeygen_002did_002dkey"></a> 1534 1535<p>This is the “write iff or gq identity keys” option. 1536</p> 1537<p>This option has some usage constraints. It: 1538</p><ul> 1539<li> must be compiled in by defining <code>AUTOKEY</code> during the compilation. 1540</li></ul> 1541 1542<p>Write the public parameters from the IFF or GQ client keys to 1543the standard output. 1544This is intended for automatic key distribution by email. 1545</p><hr> 1546<a name="ntp_002dkeygen-gq_002dparams"></a> 1547<div class="header"> 1548<p> 1549Next: <a href="#ntp_002dkeygen-host_002dkey" accesskey="n" rel="next">ntp-keygen host-key</a>, Previous: <a href="#ntp_002dkeygen-id_002dkey" accesskey="p" rel="prev">ntp-keygen id-key</a>, Up: <a href="#ntp_002dkeygen-Invocation" accesskey="u" rel="up">ntp-keygen Invocation</a> </p> 1550</div> 1551<a name="gq_002dparams-option-_0028_002dG_0029"></a> 1552<h4 class="subsection">1.2.7 gq-params option (-G)</h4> 1553<a name="index-ntp_002dkeygen_002dgq_002dparams"></a> 1554 1555<p>This is the “generate gq parameters and keys” option. 1556</p> 1557<p>This option has some usage constraints. It: 1558</p><ul> 1559<li> must be compiled in by defining <code>AUTOKEY</code> during the compilation. 1560</li></ul> 1561 1562<p>Generate parameters and keys for the GQ identification scheme, 1563obsoleting any that may exist. 1564</p><hr> 1565<a name="ntp_002dkeygen-host_002dkey"></a> 1566<div class="header"> 1567<p> 1568Next: <a href="#ntp_002dkeygen-iffkey" accesskey="n" rel="next">ntp-keygen iffkey</a>, Previous: <a href="#ntp_002dkeygen-gq_002dparams" accesskey="p" rel="prev">ntp-keygen gq-params</a>, Up: <a href="#ntp_002dkeygen-Invocation" accesskey="u" rel="up">ntp-keygen Invocation</a> </p> 1569</div> 1570<a name="host_002dkey-option-_0028_002dH_0029"></a> 1571<h4 class="subsection">1.2.8 host-key option (-H)</h4> 1572<a name="index-ntp_002dkeygen_002dhost_002dkey"></a> 1573 1574<p>This is the “generate rsa host key” option. 1575</p> 1576<p>This option has some usage constraints. It: 1577</p><ul> 1578<li> must be compiled in by defining <code>AUTOKEY</code> during the compilation. 1579</li></ul> 1580 1581<p>Generate new host keys, obsoleting any that may exist. 1582</p><hr> 1583<a name="ntp_002dkeygen-iffkey"></a> 1584<div class="header"> 1585<p> 1586Next: <a href="#ntp_002dkeygen-ident" accesskey="n" rel="next">ntp-keygen ident</a>, Previous: <a href="#ntp_002dkeygen-host_002dkey" accesskey="p" rel="prev">ntp-keygen host-key</a>, Up: <a href="#ntp_002dkeygen-Invocation" accesskey="u" rel="up">ntp-keygen Invocation</a> </p> 1587</div> 1588<a name="iffkey-option-_0028_002dI_0029"></a> 1589<h4 class="subsection">1.2.9 iffkey option (-I)</h4> 1590<a name="index-ntp_002dkeygen_002diffkey"></a> 1591 1592<p>This is the “generate iff parameters” option. 1593</p> 1594<p>This option has some usage constraints. It: 1595</p><ul> 1596<li> must be compiled in by defining <code>AUTOKEY</code> during the compilation. 1597</li></ul> 1598 1599<p>Generate parameters for the IFF identification scheme, obsoleting 1600any that may exist. 1601</p><hr> 1602<a name="ntp_002dkeygen-ident"></a> 1603<div class="header"> 1604<p> 1605Next: <a href="#ntp_002dkeygen-lifetime" accesskey="n" rel="next">ntp-keygen lifetime</a>, Previous: <a href="#ntp_002dkeygen-iffkey" accesskey="p" rel="prev">ntp-keygen iffkey</a>, Up: <a href="#ntp_002dkeygen-Invocation" accesskey="u" rel="up">ntp-keygen Invocation</a> </p> 1606</div> 1607<a name="ident-option-_0028_002di_0029"></a> 1608<h4 class="subsection">1.2.10 ident option (-i)</h4> 1609<a name="index-ntp_002dkeygen_002dident"></a> 1610 1611<p>This is the “set autokey group name” option. 1612This option takes a string argument <samp>group</samp>. 1613</p> 1614<p>This option has some usage constraints. It: 1615</p><ul> 1616<li> must be compiled in by defining <code>AUTOKEY</code> during the compilation. 1617</li></ul> 1618 1619<p>Set the optional Autokey group name to name. This is used in 1620the file name of IFF, GQ, and MV client parameters files. In 1621that role, the default is the host name if this option is not 1622provided. The group name, if specified using <code>-i/--ident</code> or 1623using <code>-s/--subject-name</code> following an ’<code>@</code>’ character, 1624is also a part of the self-signed host certificate subject and 1625issuer names in the form <code>host@group</code> and should match the 1626’<code>crypto ident</code>’ or ’<code>server ident</code>’ configuration in the 1627<code>ntpd</code> configuration file. 1628</p><hr> 1629<a name="ntp_002dkeygen-lifetime"></a> 1630<div class="header"> 1631<p> 1632Next: <a href="#ntp_002dkeygen-modulus" accesskey="n" rel="next">ntp-keygen modulus</a>, Previous: <a href="#ntp_002dkeygen-ident" accesskey="p" rel="prev">ntp-keygen ident</a>, Up: <a href="#ntp_002dkeygen-Invocation" accesskey="u" rel="up">ntp-keygen Invocation</a> </p> 1633</div> 1634<a name="lifetime-option-_0028_002dl_0029"></a> 1635<h4 class="subsection">1.2.11 lifetime option (-l)</h4> 1636<a name="index-ntp_002dkeygen_002dlifetime"></a> 1637 1638<p>This is the “set certificate lifetime” option. 1639This option takes a number argument <samp>lifetime</samp>. 1640</p> 1641<p>This option has some usage constraints. It: 1642</p><ul> 1643<li> must be compiled in by defining <code>AUTOKEY</code> during the compilation. 1644</li></ul> 1645 1646<p>Set the certificate expiration to lifetime days from now. 1647</p><hr> 1648<a name="ntp_002dkeygen-modulus"></a> 1649<div class="header"> 1650<p> 1651Next: <a href="#ntp_002dkeygen-md5key" accesskey="n" rel="next">ntp-keygen md5key</a>, Previous: <a href="#ntp_002dkeygen-lifetime" accesskey="p" rel="prev">ntp-keygen lifetime</a>, Up: <a href="#ntp_002dkeygen-Invocation" accesskey="u" rel="up">ntp-keygen Invocation</a> </p> 1652</div> 1653<a name="modulus-option-_0028_002dm_0029"></a> 1654<h4 class="subsection">1.2.12 modulus option (-m)</h4> 1655<a name="index-ntp_002dkeygen_002dmodulus"></a> 1656 1657<p>This is the “prime modulus” option. 1658This option takes a number argument <samp>modulus</samp>. 1659</p> 1660<p>This option has some usage constraints. It: 1661</p><ul> 1662<li> must be compiled in by defining <code>AUTOKEY</code> during the compilation. 1663</li></ul> 1664 1665<p>The number of bits in the prime modulus. The default is 512. 1666</p><hr> 1667<a name="ntp_002dkeygen-md5key"></a> 1668<div class="header"> 1669<p> 1670Next: <a href="#ntp_002dkeygen-pvt_002dcert" accesskey="n" rel="next">ntp-keygen pvt-cert</a>, Previous: <a href="#ntp_002dkeygen-modulus" accesskey="p" rel="prev">ntp-keygen modulus</a>, Up: <a href="#ntp_002dkeygen-Invocation" accesskey="u" rel="up">ntp-keygen Invocation</a> </p> 1671</div> 1672<a name="md5key-option-_0028_002dM_0029"></a> 1673<h4 class="subsection">1.2.13 md5key option (-M)</h4> 1674<a name="index-ntp_002dkeygen_002dmd5key"></a> 1675 1676<p>This is the “generate symmetric keys” option. 1677Generate symmetric keys, obsoleting any that may exist. 1678</p><hr> 1679<a name="ntp_002dkeygen-pvt_002dcert"></a> 1680<div class="header"> 1681<p> 1682Next: <a href="#ntp_002dkeygen-password" accesskey="n" rel="next">ntp-keygen password</a>, Previous: <a href="#ntp_002dkeygen-md5key" accesskey="p" rel="prev">ntp-keygen md5key</a>, Up: <a href="#ntp_002dkeygen-Invocation" accesskey="u" rel="up">ntp-keygen Invocation</a> </p> 1683</div> 1684<a name="pvt_002dcert-option-_0028_002dP_0029"></a> 1685<h4 class="subsection">1.2.14 pvt-cert option (-P)</h4> 1686<a name="index-ntp_002dkeygen_002dpvt_002dcert"></a> 1687 1688<p>This is the “generate pc private certificate” option. 1689</p> 1690<p>This option has some usage constraints. It: 1691</p><ul> 1692<li> must be compiled in by defining <code>AUTOKEY</code> during the compilation. 1693</li></ul> 1694 1695<p>Generate a private certificate. By default, the program generates 1696public certificates. 1697</p><hr> 1698<a name="ntp_002dkeygen-password"></a> 1699<div class="header"> 1700<p> 1701Next: <a href="#ntp_002dkeygen-export_002dpasswd" accesskey="n" rel="next">ntp-keygen export-passwd</a>, Previous: <a href="#ntp_002dkeygen-pvt_002dcert" accesskey="p" rel="prev">ntp-keygen pvt-cert</a>, Up: <a href="#ntp_002dkeygen-Invocation" accesskey="u" rel="up">ntp-keygen Invocation</a> </p> 1702</div> 1703<a name="password-option-_0028_002dp_0029"></a> 1704<h4 class="subsection">1.2.15 password option (-p)</h4> 1705<a name="index-ntp_002dkeygen_002dpassword"></a> 1706 1707<p>This is the “local private password” option. 1708This option takes a string argument <samp>passwd</samp>. 1709</p> 1710<p>This option has some usage constraints. It: 1711</p><ul> 1712<li> must be compiled in by defining <code>AUTOKEY</code> during the compilation. 1713</li></ul> 1714 1715<p>Local files containing private data are encrypted with the 1716DES-CBC algorithm and the specified password. The same password 1717must be specified to the local ntpd via the "crypto pw password" 1718configuration command. The default password is the local 1719hostname. 1720</p><hr> 1721<a name="ntp_002dkeygen-export_002dpasswd"></a> 1722<div class="header"> 1723<p> 1724Next: <a href="#ntp_002dkeygen-subject_002dname" accesskey="n" rel="next">ntp-keygen subject-name</a>, Previous: <a href="#ntp_002dkeygen-password" accesskey="p" rel="prev">ntp-keygen password</a>, Up: <a href="#ntp_002dkeygen-Invocation" accesskey="u" rel="up">ntp-keygen Invocation</a> </p> 1725</div> 1726<a name="export_002dpasswd-option-_0028_002dq_0029"></a> 1727<h4 class="subsection">1.2.16 export-passwd option (-q)</h4> 1728<a name="index-ntp_002dkeygen_002dexport_002dpasswd"></a> 1729 1730<p>This is the “export iff or gq group keys with password” option. 1731This option takes a string argument <samp>passwd</samp>. 1732</p> 1733<p>This option has some usage constraints. It: 1734</p><ul> 1735<li> must be compiled in by defining <code>AUTOKEY</code> during the compilation. 1736</li></ul> 1737 1738<p>Export IFF or GQ identity group keys to the standard output, 1739encrypted with the DES-CBC algorithm and the specified password. 1740The same password must be specified to the remote ntpd via the 1741"crypto pw password" configuration command. See also the option 1742–id-key (-e) for unencrypted exports. 1743</p><hr> 1744<a name="ntp_002dkeygen-subject_002dname"></a> 1745<div class="header"> 1746<p> 1747Next: <a href="#ntp_002dkeygen-sign_002dkey" accesskey="n" rel="next">ntp-keygen sign-key</a>, Previous: <a href="#ntp_002dkeygen-export_002dpasswd" accesskey="p" rel="prev">ntp-keygen export-passwd</a>, Up: <a href="#ntp_002dkeygen-Invocation" accesskey="u" rel="up">ntp-keygen Invocation</a> </p> 1748</div> 1749<a name="subject_002dname-option-_0028_002ds_0029"></a> 1750<h4 class="subsection">1.2.17 subject-name option (-s)</h4> 1751<a name="index-ntp_002dkeygen_002dsubject_002dname"></a> 1752 1753<p>This is the “set host and optionally group name” option. 1754This option takes a string argument <samp>host@group</samp>. 1755</p> 1756<p>This option has some usage constraints. It: 1757</p><ul> 1758<li> must be compiled in by defining <code>AUTOKEY</code> during the compilation. 1759</li></ul> 1760 1761<p>Set the Autokey host name, and optionally, group name specified 1762following an ’<code>@</code>’ character. The host name is used in the file 1763name of generated host and signing certificates, without the 1764group name. The host name, and if provided, group name are used 1765in <code>host@group</code> form for the host certificate subject and issuer 1766fields. Specifying ’<code>-s @group</code>’ is allowed, and results in 1767leaving the host name unchanged while appending <code>@group</code> to the 1768subject and issuer fields, as with <code>-i group</code>. The group name, or 1769if not provided, the host name are also used in the file names 1770of IFF, GQ, and MV client parameter files. 1771</p><hr> 1772<a name="ntp_002dkeygen-sign_002dkey"></a> 1773<div class="header"> 1774<p> 1775Next: <a href="#ntp_002dkeygen-trusted_002dcert" accesskey="n" rel="next">ntp-keygen trusted-cert</a>, Previous: <a href="#ntp_002dkeygen-subject_002dname" accesskey="p" rel="prev">ntp-keygen subject-name</a>, Up: <a href="#ntp_002dkeygen-Invocation" accesskey="u" rel="up">ntp-keygen Invocation</a> </p> 1776</div> 1777<a name="sign_002dkey-option-_0028_002dS_0029"></a> 1778<h4 class="subsection">1.2.18 sign-key option (-S)</h4> 1779<a name="index-ntp_002dkeygen_002dsign_002dkey"></a> 1780 1781<p>This is the “generate sign key (rsa or dsa)” option. 1782This option takes a string argument <samp>sign</samp>. 1783</p> 1784<p>This option has some usage constraints. It: 1785</p><ul> 1786<li> must be compiled in by defining <code>AUTOKEY</code> during the compilation. 1787</li></ul> 1788 1789<p>Generate a new sign key of the designated type, obsoleting any 1790that may exist. By default, the program uses the host key as the 1791sign key. 1792</p><hr> 1793<a name="ntp_002dkeygen-trusted_002dcert"></a> 1794<div class="header"> 1795<p> 1796Next: <a href="#ntp_002dkeygen-mv_002dparams" accesskey="n" rel="next">ntp-keygen mv-params</a>, Previous: <a href="#ntp_002dkeygen-sign_002dkey" accesskey="p" rel="prev">ntp-keygen sign-key</a>, Up: <a href="#ntp_002dkeygen-Invocation" accesskey="u" rel="up">ntp-keygen Invocation</a> </p> 1797</div> 1798<a name="trusted_002dcert-option-_0028_002dT_0029"></a> 1799<h4 class="subsection">1.2.19 trusted-cert option (-T)</h4> 1800<a name="index-ntp_002dkeygen_002dtrusted_002dcert"></a> 1801 1802<p>This is the “trusted certificate (tc scheme)” option. 1803</p> 1804<p>This option has some usage constraints. It: 1805</p><ul> 1806<li> must be compiled in by defining <code>AUTOKEY</code> during the compilation. 1807</li></ul> 1808 1809<p>Generate a trusted certificate. By default, the program generates 1810a non-trusted certificate. 1811</p><hr> 1812<a name="ntp_002dkeygen-mv_002dparams"></a> 1813<div class="header"> 1814<p> 1815Next: <a href="#ntp_002dkeygen-mv_002dkeys" accesskey="n" rel="next">ntp-keygen mv-keys</a>, Previous: <a href="#ntp_002dkeygen-trusted_002dcert" accesskey="p" rel="prev">ntp-keygen trusted-cert</a>, Up: <a href="#ntp_002dkeygen-Invocation" accesskey="u" rel="up">ntp-keygen Invocation</a> </p> 1816</div> 1817<a name="mv_002dparams-option-_0028_002dV_0029"></a> 1818<h4 class="subsection">1.2.20 mv-params option (-V)</h4> 1819<a name="index-ntp_002dkeygen_002dmv_002dparams"></a> 1820 1821<p>This is the “generate <num> mv parameters” option. 1822This option takes a number argument <samp>num</samp>. 1823</p> 1824<p>This option has some usage constraints. It: 1825</p><ul> 1826<li> must be compiled in by defining <code>AUTOKEY</code> during the compilation. 1827</li></ul> 1828 1829<p>Generate parameters and keys for the Mu-Varadharajan (MV) 1830identification scheme. 1831</p><hr> 1832<a name="ntp_002dkeygen-mv_002dkeys"></a> 1833<div class="header"> 1834<p> 1835Next: <a href="#ntp_002dkeygen-config" accesskey="n" rel="next">ntp-keygen config</a>, Previous: <a href="#ntp_002dkeygen-mv_002dparams" accesskey="p" rel="prev">ntp-keygen mv-params</a>, Up: <a href="#ntp_002dkeygen-Invocation" accesskey="u" rel="up">ntp-keygen Invocation</a> </p> 1836</div> 1837<a name="mv_002dkeys-option-_0028_002dv_0029"></a> 1838<h4 class="subsection">1.2.21 mv-keys option (-v)</h4> 1839<a name="index-ntp_002dkeygen_002dmv_002dkeys"></a> 1840 1841<p>This is the “update <num> mv keys” option. 1842This option takes a number argument <samp>num</samp>. 1843</p> 1844<p>This option has some usage constraints. It: 1845</p><ul> 1846<li> must be compiled in by defining <code>AUTOKEY</code> during the compilation. 1847</li></ul> 1848 1849<p>This option has no ‘<samp>doc</samp>’ documentation. 1850</p> 1851 1852<hr> 1853<a name="ntp_002dkeygen-config"></a> 1854<div class="header"> 1855<p> 1856Next: <a href="#ntp_002dkeygen-exit-status" accesskey="n" rel="next">ntp-keygen exit status</a>, Previous: <a href="#ntp_002dkeygen-mv_002dkeys" accesskey="p" rel="prev">ntp-keygen mv-keys</a>, Up: <a href="#ntp_002dkeygen-Invocation" accesskey="u" rel="up">ntp-keygen Invocation</a> </p> 1857</div> 1858<a name="presetting_002fconfiguring-ntp_002dkeygen"></a> 1859<h4 class="subsection">1.2.22 presetting/configuring ntp-keygen</h4> 1860 1861<p>Any option that is not marked as <i>not presettable</i> may be preset by 1862loading values from configuration ("rc" or "ini") files, and values from environment variables named <code>NTP-KEYGEN</code> and <code>NTP-KEYGEN_<OPTION_NAME></code>. <code><OPTION_NAME></code> must be one of 1863the options listed above in upper case and segmented with underscores. 1864The <code>NTP-KEYGEN</code> variable will be tokenized and parsed like 1865the command line. The remaining variables are tested for existence and their 1866values are treated like option arguments. 1867</p> 1868 1869<p><code>libopts</code> will search in 2 places for configuration files: 1870</p><ul> 1871<li> $HOME 1872</li><li> $PWD 1873</li></ul> 1874<p>The environment variables <code>HOME</code>, and <code>PWD</code> 1875are expanded and replaced when <samp>ntp-keygen</samp> runs. 1876For any of these that are plain files, they are simply processed. 1877For any that are directories, then a file named <samp>.ntprc</samp> is searched for 1878within that directory and processed. 1879</p> 1880<p>Configuration files may be in a wide variety of formats. 1881The basic format is an option name followed by a value (argument) on the 1882same line. Values may be separated from the option name with a colon, 1883equal sign or simply white space. Values may be continued across multiple 1884lines by escaping the newline with a backslash. 1885</p> 1886<p>Multiple programs may also share the same initialization file. 1887Common options are collected at the top, followed by program specific 1888segments. The segments are separated by lines like: 1889</p><div class="example"> 1890<pre class="example">[NTP-KEYGEN] 1891</pre></div> 1892<p>or by 1893</p><div class="example"> 1894<pre class="example"><?program ntp-keygen> 1895</pre></div> 1896<p>Do not mix these styles within one configuration file. 1897</p> 1898<p>Compound values and carefully constructed string values may also be 1899specified using XML syntax: 1900</p><div class="example"> 1901<pre class="example"><option-name> 1902 <sub-opt>...&lt;...&gt;...</sub-opt> 1903</option-name> 1904</pre></div> 1905<p>yielding an <code>option-name.sub-opt</code> string value of 1906</p><div class="example"> 1907<pre class="example">"...<...>..." 1908</pre></div> 1909<p><code>AutoOpts</code> does not track suboptions. You simply note that it is a 1910hierarchicly valued option. <code>AutoOpts</code> does provide a means for searching 1911the associated name/value pair list (see: optionFindValue). 1912</p> 1913<p>The command line options relating to configuration and/or usage help are: 1914</p> 1915<a name="version-_0028_002d_0029"></a> 1916<h4 class="subsubheading">version (-)</h4> 1917 1918<p>Print the program version to standard out, optionally with licensing 1919information, then exit 0. The optional argument specifies how much licensing 1920detail to provide. The default is to print just the version. The licensing infomation may be selected with an option argument. 1921Only the first letter of the argument is examined: 1922</p> 1923<dl compact="compact"> 1924<dt>‘<samp>version</samp>’</dt> 1925<dd><p>Only print the version. This is the default. 1926</p></dd> 1927<dt>‘<samp>copyright</samp>’</dt> 1928<dd><p>Name the copyright usage licensing terms. 1929</p></dd> 1930<dt>‘<samp>verbose</samp>’</dt> 1931<dd><p>Print the full copyright usage licensing terms. 1932</p></dd> 1933</dl> 1934 1935<hr> 1936<a name="ntp_002dkeygen-exit-status"></a> 1937<div class="header"> 1938<p> 1939Next: <a href="#ntp_002dkeygen-Usage" accesskey="n" rel="next">ntp-keygen Usage</a>, Previous: <a href="#ntp_002dkeygen-config" accesskey="p" rel="prev">ntp-keygen config</a>, Up: <a href="#ntp_002dkeygen-Invocation" accesskey="u" rel="up">ntp-keygen Invocation</a> </p> 1940</div> 1941<a name="ntp_002dkeygen-exit-status-1"></a> 1942<h4 class="subsection">1.2.23 ntp-keygen exit status</h4> 1943 1944<p>One of the following exit values will be returned: 1945</p><dl compact="compact"> 1946<dt>‘<samp>0 (EXIT_SUCCESS)</samp>’</dt> 1947<dd><p>Successful program execution. 1948</p></dd> 1949<dt>‘<samp>1 (EXIT_FAILURE)</samp>’</dt> 1950<dd><p>The operation failed or the command syntax was not valid. 1951</p></dd> 1952<dt>‘<samp>66 (EX_NOINPUT)</samp>’</dt> 1953<dd><p>A specified configuration file could not be loaded. 1954</p></dd> 1955<dt>‘<samp>70 (EX_SOFTWARE)</samp>’</dt> 1956<dd><p>libopts had an internal operational error. Please report 1957it to autogen-users@lists.sourceforge.net. Thank you. 1958</p></dd> 1959</dl> 1960<hr> 1961<a name="ntp_002dkeygen-Usage"></a> 1962<div class="header"> 1963<p> 1964Next: <a href="#ntp_002dkeygen-Notes" accesskey="n" rel="next">ntp-keygen Notes</a>, Previous: <a href="#ntp_002dkeygen-exit-status" accesskey="p" rel="prev">ntp-keygen exit status</a>, Up: <a href="#ntp_002dkeygen-Invocation" accesskey="u" rel="up">ntp-keygen Invocation</a> </p> 1965</div> 1966<a name="ntp_002dkeygen-Usage-1"></a> 1967<h4 class="subsection">1.2.24 ntp-keygen Usage</h4> 1968<hr> 1969<a name="ntp_002dkeygen-Notes"></a> 1970<div class="header"> 1971<p> 1972Next: <a href="#ntp_002dkeygen-Bugs" accesskey="n" rel="next">ntp-keygen Bugs</a>, Previous: <a href="#ntp_002dkeygen-Usage" accesskey="p" rel="prev">ntp-keygen Usage</a>, Up: <a href="#ntp_002dkeygen-Invocation" accesskey="u" rel="up">ntp-keygen Invocation</a> </p> 1973</div> 1974<a name="ntp_002dkeygen-Notes-1"></a> 1975<h4 class="subsection">1.2.25 ntp-keygen Notes</h4> 1976<hr> 1977<a name="ntp_002dkeygen-Bugs"></a> 1978<div class="header"> 1979<p> 1980Previous: <a href="#ntp_002dkeygen-Notes" accesskey="p" rel="prev">ntp-keygen Notes</a>, Up: <a href="#ntp_002dkeygen-Invocation" accesskey="u" rel="up">ntp-keygen Invocation</a> </p> 1981</div> 1982<a name="ntp_002dkeygen-Bugs-1"></a> 1983<h4 class="subsection">1.2.26 ntp-keygen Bugs</h4> 1984 1985<hr> 1986<a name="Random-Seed-File"></a> 1987<div class="header"> 1988<p> 1989Next: <a href="#Cryptographic-Data-Files" accesskey="n" rel="next">Cryptographic Data Files</a>, Previous: <a href="#Running-the-Program" accesskey="p" rel="prev">Running the Program</a>, Up: <a href="#Top" accesskey="u" rel="up">Top</a> </p> 1990</div> 1991<a name="Random-Seed-File-2"></a> 1992<h3 class="section">1.3 Random Seed File</h3> 1993 1994<p>All cryptographically sound key generation schemes must have means to 1995randomize the entropy seed used to initialize the internal 1996pseudo-random number generator used by the OpenSSL library routines. 1997If a site supports ssh, it is very likely that means to do this are 1998already available. 1999The entropy seed used by the OpenSSL library is contained in a file, 2000usually called <code>.rnd</code>, which must be available when 2001starting the <code>ntp-keygen</code> program or <code>ntpd</code> daemon. 2002</p> 2003<p>The OpenSSL library looks for the file using the path specified by the 2004<code>RANDFILE</code> environment variable in the user home directory, whether root 2005or some other user. 2006If the <code>RANDFILE</code> environment variable is not 2007present, the library looks for the <code>.rnd</code> file in the user home 2008directory. 2009Since both the <code>ntp-keygen</code> program and <code>ntpd</code> daemon must run 2010as root, the logical place to put this file is in <code>/.rnd</code> or 2011<code>/root/.rnd</code>. 2012If the file is not available or cannot be written, the program exits 2013with a message to the system log. 2014</p> 2015<hr> 2016<a name="Cryptographic-Data-Files"></a> 2017<div class="header"> 2018<p> 2019Previous: <a href="#Random-Seed-File" accesskey="p" rel="prev">Random Seed File</a>, Up: <a href="#Top" accesskey="u" rel="up">Top</a> </p> 2020</div> 2021<a name="Cryptographic-Data-Files-2"></a> 2022<h3 class="section">1.4 Cryptographic Data Files</h3> 2023 2024<p>File and link names are in the <code>form ntpkey_key_name.fstamp</code>, 2025where <code>key</code> is the key or parameter type, 2026<code>name</code> is the host or group name and 2027<code>fstamp</code> is the filestamp (NTP seconds) when the file was created). 2028By convention, key names in generated file names include both upper and 2029lower case characters, while key names in generated link names include 2030only lower case characters. The filestamp is not used in generated link 2031names. 2032</p> 2033<p>The key name is a string defining the cryptographic key type. 2034Key types include public/private keys host and sign, certificate cert 2035and several challenge/response key types. 2036By convention, client files used for 2037challenges have a par subtype, as in the IFF challenge IFFpar, while 2038server files for responses have a key subtype, as in the GQ response 2039GQkey. 2040</p> 2041<p>All files begin with two nonencrypted lines. The first line contains 2042the file name in the format <code>ntpkey_key_host.fstamp</code>. 2043The second line contains the datestamp in conventional Unix date format. 2044Lines beginning with <code>#</code> are ignored. 2045</p> 2046<p>The remainder of the file contains cryptographic data encoded first 2047using ASN.1 rules, then encrypted using the DES-CBC algorithm with 2048given password and finally written in PEM-encoded printable ASCII text 2049preceded and followed by MIME content identifier lines. 2050</p> 2051<p>The format of the symmetric keys file, ordinarily named <code>ntp.keys</code>, 2052is somewhat different than the other files in the interest of backward 2053compatibility. 2054Ordinarily, the file is generated by this program, but 2055it can be constructed and edited using an ordinary text editor. 2056</p> 2057<div class="example"> 2058<pre class="example"># ntpkey_MD5key_hms.local.3564038757 2059# Sun Dec 9 02:45:57 2012 2060 2061 1 MD5 "]!ghT%O;3)WJ,/Nc:>I # MD5 key 2062 2 MD5 lu+H^tF46BKR-6~pV_5 # MD5 key 2063 3 MD5 :lnoVsE%Yz*avh%EtNC # MD5 key 2064 4 MD5 |fdZrf0sF~;w-i^V # MD5 key 2065 5 MD5 IyAG>O"y"LmCRS!*bHC # MD5 key 2066 6 MD5 ">e\A>hT/661ri52,,H # MD5 key 2067 7 MD5 c9x=M'CfLxax9v)PV-si # MD5 key 2068 8 MD5 E|=jvFVov?Bn|Ev=&aK\ # MD5 key 2069 9 MD5 T!c4UT&`(m$+m+B6,`Q0 # MD5 key 207010 MD5 JVF/1=)=IFbHbJQz..Cd # MD5 key 207111 SHA1 6dea311109529e436c2b4fccae9bc753c16d1b48 # SHA1 key 207212 SHA1 7076f373d86c4848c59ff8046e49cb7d614ec394 # SHA1 key 207313 SHA1 5f48b1b60591eb01b7cf1d33b7774f08d20262d3 # SHA1 key 207414 SHA1 eed5ab9d9497319ec60cf3781d52607e76720178 # SHA1 key 207515 SHA1 f283562611a04c964da8126296f5f8e58c3f85de # SHA1 key 207616 SHA1 1930da171297dd63549af50b29449de17dcf341f # SHA1 key 207717 SHA1 fee892110358cd4382322b889869e750db8e8a8f # SHA1 key 207818 SHA1 b5520c9fadd7ad3fd8bfa061c8821b65d029bb37 # SHA1 key 207919 SHA1 8c74fb440ec80f453ec6aaa62b9baed0ab723b92 # SHA1 key 208020 SHA1 6bc05f734306a189326000970c19b3910f403795 # SHA1 key 2081</pre></div> 2082 2083<p>Figure 1. Typical Symmetric Key File 2084</p> 2085<p>Figure 1 shows a typical symmetric keys file used by the reference 2086implementation. 2087Each line of the file contains three fields, first an 2088integer between 1 and 65535, inclusive, representing the key identifier 2089used in the server and peer configuration commands. 2090Next is the key type for the message digest algorithm, 2091which in the absence of the 2092OpenSSL library must be MD5 to designate the MD5 message digest 2093algorithm. 2094If the OpenSSL library is installed, the key type can be any 2095message digest algorithm supported by that library. 2096However, if 2097compatibility with FIPS 140-2 is required, the key type must be either 2098SHA or SHA1. 2099The key type can be changed using an ASCII text editor. 2100</p> 2101<p>An MD5 key consists of a printable ASCII string less than or equal to 210216 characters and terminated by whitespace or a # character. 2103An OpenSSL 2104key consists of a hex-encoded ASCII string of 40 characters, which is 2105truncated as necessary. 2106</p> 2107<p>Note that the keys used by the <code>ntpq</code> and <code>ntpdc</code> programs are 2108checked against passwords requested by the programs and entered by hand, 2109so it 2110is generally appropriate to specify these keys in human readable ASCII 2111format. 2112</p> 2113<p>The <code>ntp-keygen</code> program generates a MD5 symmetric keys file 2114<code>ntpkey_MD5key_hostname.filestamp</code>. 2115Since the file contains private 2116shared keys, it should be visible only to root and distributed by 2117secure means to other subnet hosts. 2118The NTP daemon loads the file <code>ntp.keys</code>, so <code>ntp-keygen</code> 2119installs a soft link from this name to the generated file. 2120Subsequently, similar soft links must be installed by 2121manual or automated means on the other subnet hosts. 2122While this file is 2123not used with the Autokey Version 2 protocol, it is needed to 2124authenticate some remote configuration commands used by the <code>ntpq</code> and 2125<code>ntpdc</code> utilities. 2126</p><hr> 2127 2128 2129 2130</body> 2131</html> 2132