cms.pod revision 306196
1=pod 2 3=head1 NAME 4 5cms - CMS utility 6 7=head1 SYNOPSIS 8 9B<openssl> B<cms> 10[B<-encrypt>] 11[B<-decrypt>] 12[B<-sign>] 13[B<-verify>] 14[B<-cmsout>] 15[B<-resign>] 16[B<-data_create>] 17[B<-data_out>] 18[B<-digest_create>] 19[B<-digest_verify>] 20[B<-compress>] 21[B<-uncompress>] 22[B<-EncryptedData_encrypt>] 23[B<-sign_receipt>] 24[B<-verify_receipt receipt>] 25[B<-in filename>] 26[B<-inform SMIME|PEM|DER>] 27[B<-rctform SMIME|PEM|DER>] 28[B<-out filename>] 29[B<-outform SMIME|PEM|DER>] 30[B<-stream -indef -noindef>] 31[B<-noindef>] 32[B<-content filename>] 33[B<-text>] 34[B<-noout>] 35[B<-print>] 36[B<-CAfile file>] 37[B<-CApath dir>] 38[B<-no_alt_chains>] 39[B<-md digest>] 40[B<-[cipher]>] 41[B<-nointern>] 42[B<-no_signer_cert_verify>] 43[B<-nocerts>] 44[B<-noattr>] 45[B<-nosmimecap>] 46[B<-binary>] 47[B<-nodetach>] 48[B<-certfile file>] 49[B<-certsout file>] 50[B<-signer file>] 51[B<-recip file>] 52[B<-keyid>] 53[B<-receipt_request_all -receipt_request_first>] 54[B<-receipt_request_from emailaddress>] 55[B<-receipt_request_to emailaddress>] 56[B<-receipt_request_print>] 57[B<-secretkey key>] 58[B<-secretkeyid id>] 59[B<-econtent_type type>] 60[B<-inkey file>] 61[B<-passin arg>] 62[B<-rand file(s)>] 63[B<cert.pem...>] 64[B<-to addr>] 65[B<-from addr>] 66[B<-subject subj>] 67[cert.pem]... 68 69=head1 DESCRIPTION 70 71The B<cms> command handles S/MIME v3.1 mail. It can encrypt, decrypt, sign and 72verify, compress and uncompress S/MIME messages. 73 74=head1 COMMAND OPTIONS 75 76There are fourteen operation options that set the type of operation to be 77performed. The meaning of the other options varies according to the operation 78type. 79 80=over 4 81 82=item B<-encrypt> 83 84encrypt mail for the given recipient certificates. Input file is the message 85to be encrypted. The output file is the encrypted mail in MIME format. The 86actual CMS type is <B>EnvelopedData<B>. 87 88Note that no revocation check is done for the recipient cert, so if that 89key has been compromised, others may be able to decrypt the text. 90 91=item B<-decrypt> 92 93decrypt mail using the supplied certificate and private key. Expects an 94encrypted mail message in MIME format for the input file. The decrypted mail 95is written to the output file. 96 97=item B<-debug_decrypt> 98 99this option sets the B<CMS_DEBUG_DECRYPT> flag. This option should be used 100with caution: see the notes section below. 101 102=item B<-sign> 103 104sign mail using the supplied certificate and private key. Input file is 105the message to be signed. The signed message in MIME format is written 106to the output file. 107 108=item B<-verify> 109 110verify signed mail. Expects a signed mail message on input and outputs 111the signed data. Both clear text and opaque signing is supported. 112 113=item B<-cmsout> 114 115takes an input message and writes out a PEM encoded CMS structure. 116 117=item B<-resign> 118 119resign a message: take an existing message and one or more new signers. 120 121=item B<-data_create> 122 123Create a CMS B<Data> type. 124 125=item B<-data_out> 126 127B<Data> type and output the content. 128 129=item B<-digest_create> 130 131Create a CMS B<DigestedData> type. 132 133=item B<-digest_verify> 134 135Verify a CMS B<DigestedData> type and output the content. 136 137=item B<-compress> 138 139Create a CMS B<CompressedData> type. OpenSSL must be compiled with B<zlib> 140support for this option to work, otherwise it will output an error. 141 142=item B<-uncompress> 143 144Uncompress a CMS B<CompressedData> type and output the content. OpenSSL must be 145compiled with B<zlib> support for this option to work, otherwise it will 146output an error. 147 148=item B<-EncryptedData_encrypt> 149 150Encrypt content using supplied symmetric key and algorithm using a CMS 151B<EncrytedData> type and output the content. 152 153=item B<-sign_receipt> 154 155Generate and output a signed receipt for the supplied message. The input 156message B<must> contain a signed receipt request. Functionality is otherwise 157similar to the B<-sign> operation. 158 159=item B<-verify_receipt receipt> 160 161Verify a signed receipt in filename B<receipt>. The input message B<must> 162contain the original receipt request. Functionality is otherwise similar 163to the B<-verify> operation. 164 165=item B<-in filename> 166 167the input message to be encrypted or signed or the message to be decrypted 168or verified. 169 170=item B<-inform SMIME|PEM|DER> 171 172this specifies the input format for the CMS structure. The default 173is B<SMIME> which reads an S/MIME format message. B<PEM> and B<DER> 174format change this to expect PEM and DER format CMS structures 175instead. This currently only affects the input format of the CMS 176structure, if no CMS structure is being input (for example with 177B<-encrypt> or B<-sign>) this option has no effect. 178 179=item B<-rctform SMIME|PEM|DER> 180 181specify the format for a signed receipt for use with the B<-receipt_verify> 182operation. 183 184=item B<-out filename> 185 186the message text that has been decrypted or verified or the output MIME 187format message that has been signed or verified. 188 189=item B<-outform SMIME|PEM|DER> 190 191this specifies the output format for the CMS structure. The default 192is B<SMIME> which writes an S/MIME format message. B<PEM> and B<DER> 193format change this to write PEM and DER format CMS structures 194instead. This currently only affects the output format of the CMS 195structure, if no CMS structure is being output (for example with 196B<-verify> or B<-decrypt>) this option has no effect. 197 198=item B<-stream -indef -noindef> 199 200the B<-stream> and B<-indef> options are equivalent and enable streaming I/O 201for encoding operations. This permits single pass processing of data without 202the need to hold the entire contents in memory, potentially supporting very 203large files. Streaming is automatically set for S/MIME signing with detached 204data if the output format is B<SMIME> it is currently off by default for all 205other operations. 206 207=item B<-noindef> 208 209disable streaming I/O where it would produce and indefinite length constructed 210encoding. This option currently has no effect. In future streaming will be 211enabled by default on all relevant operations and this option will disable it. 212 213=item B<-content filename> 214 215This specifies a file containing the detached content, this is only 216useful with the B<-verify> command. This is only usable if the CMS 217structure is using the detached signature form where the content is 218not included. This option will override any content if the input format 219is S/MIME and it uses the multipart/signed MIME content type. 220 221=item B<-text> 222 223this option adds plain text (text/plain) MIME headers to the supplied 224message if encrypting or signing. If decrypting or verifying it strips 225off text headers: if the decrypted or verified message is not of MIME 226type text/plain then an error occurs. 227 228=item B<-noout> 229 230for the B<-cmsout> operation do not output the parsed CMS structure. This 231is useful when combined with the B<-print> option or if the syntax of the CMS 232structure is being checked. 233 234=item B<-print> 235 236for the B<-cmsout> operation print out all fields of the CMS structure. This 237is mainly useful for testing purposes. 238 239=item B<-CAfile file> 240 241a file containing trusted CA certificates, only used with B<-verify>. 242 243=item B<-CApath dir> 244 245a directory containing trusted CA certificates, only used with 246B<-verify>. This directory must be a standard certificate directory: that 247is a hash of each subject name (using B<x509 -hash>) should be linked 248to each certificate. 249 250=item B<-md digest> 251 252digest algorithm to use when signing or resigning. If not present then the 253default digest algorithm for the signing key will be used (usually SHA1). 254 255=item B<-[cipher]> 256 257the encryption algorithm to use. For example triple DES (168 bits) - B<-des3> 258or 256 bit AES - B<-aes256>. Any standard algorithm name (as used by the 259EVP_get_cipherbyname() function) can also be used preceded by a dash, for 260example B<-aes_128_cbc>. See L<B<enc>|enc(1)> for a list of ciphers 261supported by your version of OpenSSL. 262 263If not specified triple DES is used. Only used with B<-encrypt> and 264B<-EncryptedData_create> commands. 265 266=item B<-nointern> 267 268when verifying a message normally certificates (if any) included in 269the message are searched for the signing certificate. With this option 270only the certificates specified in the B<-certfile> option are used. 271The supplied certificates can still be used as untrusted CAs however. 272 273=item B<-no_signer_cert_verify> 274 275do not verify the signers certificate of a signed message. 276 277=item B<-nocerts> 278 279when signing a message the signer's certificate is normally included 280with this option it is excluded. This will reduce the size of the 281signed message but the verifier must have a copy of the signers certificate 282available locally (passed using the B<-certfile> option for example). 283 284=item B<-noattr> 285 286normally when a message is signed a set of attributes are included which 287include the signing time and supported symmetric algorithms. With this 288option they are not included. 289 290=item B<-nosmimecap> 291 292exclude the list of supported algorithms from signed attributes, other options 293such as signing time and content type are still included. 294 295=item B<-binary> 296 297normally the input message is converted to "canonical" format which is 298effectively using CR and LF as end of line: as required by the S/MIME 299specification. When this option is present no translation occurs. This 300is useful when handling binary data which may not be in MIME format. 301 302=item B<-nodetach> 303 304when signing a message use opaque signing: this form is more resistant 305to translation by mail relays but it cannot be read by mail agents that 306do not support S/MIME. Without this option cleartext signing with 307the MIME type multipart/signed is used. 308 309=item B<-certfile file> 310 311allows additional certificates to be specified. When signing these will 312be included with the message. When verifying these will be searched for 313the signers certificates. The certificates should be in PEM format. 314 315=item B<-certsout file> 316 317any certificates contained in the message are written to B<file>. 318 319=item B<-signer file> 320 321a signing certificate when signing or resigning a message, this option can be 322used multiple times if more than one signer is required. If a message is being 323verified then the signers certificates will be written to this file if the 324verification was successful. 325 326=item B<-recip file> 327 328the recipients certificate when decrypting a message. This certificate 329must match one of the recipients of the message or an error occurs. 330 331=item B<-keyid> 332 333use subject key identifier to identify certificates instead of issuer name and 334serial number. The supplied certificate B<must> include a subject key 335identifier extension. Supported by B<-sign> and B<-encrypt> options. 336 337=item B<-receipt_request_all -receipt_request_first> 338 339for B<-sign> option include a signed receipt request. Indicate requests should 340be provided by all receipient or first tier recipients (those mailed directly 341and not from a mailing list). Ignored it B<-receipt_request_from> is included. 342 343=item B<-receipt_request_from emailaddress> 344 345for B<-sign> option include a signed receipt request. Add an explicit email 346address where receipts should be supplied. 347 348=item B<-receipt_request_to emailaddress> 349 350Add an explicit email address where signed receipts should be sent to. This 351option B<must> but supplied if a signed receipt it requested. 352 353=item B<-receipt_request_print> 354 355For the B<-verify> operation print out the contents of any signed receipt 356requests. 357 358=item B<-secretkey key> 359 360specify symmetric key to use. The key must be supplied in hex format and be 361consistent with the algorithm used. Supported by the B<-EncryptedData_encrypt> 362B<-EncrryptedData_decrypt>, B<-encrypt> and B<-decrypt> options. When used 363with B<-encrypt> or B<-decrypt> the supplied key is used to wrap or unwrap the 364content encryption key using an AES key in the B<KEKRecipientInfo> type. 365 366=item B<-secretkeyid id> 367 368the key identifier for the supplied symmetric key for B<KEKRecipientInfo> type. 369This option B<must> be present if the B<-secretkey> option is used with 370B<-encrypt>. With B<-decrypt> operations the B<id> is used to locate the 371relevant key if it is not supplied then an attempt is used to decrypt any 372B<KEKRecipientInfo> structures. 373 374=item B<-econtent_type type> 375 376set the encapsulated content type to B<type> if not supplied the B<Data> type 377is used. The B<type> argument can be any valid OID name in either text or 378numerical format. 379 380=item B<-inkey file> 381 382the private key to use when signing or decrypting. This must match the 383corresponding certificate. If this option is not specified then the 384private key must be included in the certificate file specified with 385the B<-recip> or B<-signer> file. When signing this option can be used 386multiple times to specify successive keys. 387 388=item B<-passin arg> 389 390the private key password source. For more information about the format of B<arg> 391see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)|openssl(1)>. 392 393=item B<-rand file(s)> 394 395a file or files containing random data used to seed the random number 396generator, or an EGD socket (see L<RAND_egd(3)|RAND_egd(3)>). 397Multiple files can be specified separated by a OS-dependent character. 398The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for 399all others. 400 401=item B<cert.pem...> 402 403one or more certificates of message recipients: used when encrypting 404a message. 405 406=item B<-to, -from, -subject> 407 408the relevant mail headers. These are included outside the signed 409portion of a message so they may be included manually. If signing 410then many S/MIME mail clients check the signers certificate's email 411address matches that specified in the From: address. 412 413=item B<-purpose, -ignore_critical, -issuer_checks, -crl_check, -crl_check_all, -policy_check, -extended_crl, -x509_strict, -policy -check_ss_sig -no_alt_chains> 414 415Set various certificate chain valiadition option. See the 416L<B<verify>|verify(1)> manual page for details. 417 418=back 419 420=head1 NOTES 421 422The MIME message must be sent without any blank lines between the 423headers and the output. Some mail programs will automatically add 424a blank line. Piping the mail directly to sendmail is one way to 425achieve the correct format. 426 427The supplied message to be signed or encrypted must include the 428necessary MIME headers or many S/MIME clients wont display it 429properly (if at all). You can use the B<-text> option to automatically 430add plain text headers. 431 432A "signed and encrypted" message is one where a signed message is 433then encrypted. This can be produced by encrypting an already signed 434message: see the examples section. 435 436This version of the program only allows one signer per message but it 437will verify multiple signers on received messages. Some S/MIME clients 438choke if a message contains multiple signers. It is possible to sign 439messages "in parallel" by signing an already signed message. 440 441The options B<-encrypt> and B<-decrypt> reflect common usage in S/MIME 442clients. Strictly speaking these process CMS enveloped data: CMS 443encrypted data is used for other purposes. 444 445The B<-resign> option uses an existing message digest when adding a new 446signer. This means that attributes must be present in at least one existing 447signer using the same message digest or this operation will fail. 448 449The B<-stream> and B<-indef> options enable experimental streaming I/O support. 450As a result the encoding is BER using indefinite length constructed encoding 451and no longer DER. Streaming is supported for the B<-encrypt> operation and the 452B<-sign> operation if the content is not detached. 453 454Streaming is always used for the B<-sign> operation with detached data but 455since the content is no longer part of the CMS structure the encoding 456remains DER. 457 458If the B<-decrypt> option is used without a recipient certificate then an 459attempt is made to locate the recipient by trying each potential recipient 460in turn using the supplied private key. To thwart the MMA attack 461(Bleichenbacher's attack on PKCS #1 v1.5 RSA padding) all recipients are 462tried whether they succeed or not and if no recipients match the message 463is "decrypted" using a random key which will typically output garbage. 464The B<-debug_decrypt> option can be used to disable the MMA attack protection 465and return an error if no recipient can be found: this option should be used 466with caution. For a fuller description see L<CMS_decrypt(3)|CMS_decrypt(3)>). 467 468=head1 EXIT CODES 469 470=over 4 471 472=item Z<>0 473 474the operation was completely successfully. 475 476=item Z<>1 477 478an error occurred parsing the command options. 479 480=item Z<>2 481 482one of the input files could not be read. 483 484=item Z<>3 485 486an error occurred creating the CMS file or when reading the MIME 487message. 488 489=item Z<>4 490 491an error occurred decrypting or verifying the message. 492 493=item Z<>5 494 495the message was verified correctly but an error occurred writing out 496the signers certificates. 497 498=back 499 500=head1 COMPATIBILITY WITH PKCS#7 format. 501 502The B<smime> utility can only process the older B<PKCS#7> format. The B<cms> 503utility supports Cryptographic Message Syntax format. Use of some features 504will result in messages which cannot be processed by applications which only 505support the older format. These are detailed below. 506 507The use of the B<-keyid> option with B<-sign> or B<-encrypt>. 508 509The B<-outform PEM> option uses different headers. 510 511The B<-compress> option. 512 513The B<-secretkey> option when used with B<-encrypt>. 514 515Additionally the B<-EncryptedData_create> and B<-data_create> type cannot 516be processed by the older B<smime> command. 517 518=head1 EXAMPLES 519 520Create a cleartext signed message: 521 522 openssl cms -sign -in message.txt -text -out mail.msg \ 523 -signer mycert.pem 524 525Create an opaque signed message 526 527 openssl cms -sign -in message.txt -text -out mail.msg -nodetach \ 528 -signer mycert.pem 529 530Create a signed message, include some additional certificates and 531read the private key from another file: 532 533 openssl cms -sign -in in.txt -text -out mail.msg \ 534 -signer mycert.pem -inkey mykey.pem -certfile mycerts.pem 535 536Create a signed message with two signers, use key identifier: 537 538 openssl cms -sign -in message.txt -text -out mail.msg \ 539 -signer mycert.pem -signer othercert.pem -keyid 540 541Send a signed message under Unix directly to sendmail, including headers: 542 543 openssl cms -sign -in in.txt -text -signer mycert.pem \ 544 -from steve@openssl.org -to someone@somewhere \ 545 -subject "Signed message" | sendmail someone@somewhere 546 547Verify a message and extract the signer's certificate if successful: 548 549 openssl cms -verify -in mail.msg -signer user.pem -out signedtext.txt 550 551Send encrypted mail using triple DES: 552 553 openssl cms -encrypt -in in.txt -from steve@openssl.org \ 554 -to someone@somewhere -subject "Encrypted message" \ 555 -des3 user.pem -out mail.msg 556 557Sign and encrypt mail: 558 559 openssl cms -sign -in ml.txt -signer my.pem -text \ 560 | openssl cms -encrypt -out mail.msg \ 561 -from steve@openssl.org -to someone@somewhere \ 562 -subject "Signed and Encrypted message" -des3 user.pem 563 564Note: the encryption command does not include the B<-text> option because the 565message being encrypted already has MIME headers. 566 567Decrypt mail: 568 569 openssl cms -decrypt -in mail.msg -recip mycert.pem -inkey key.pem 570 571The output from Netscape form signing is a PKCS#7 structure with the 572detached signature format. You can use this program to verify the 573signature by line wrapping the base64 encoded structure and surrounding 574it with: 575 576 -----BEGIN PKCS7----- 577 -----END PKCS7----- 578 579and using the command, 580 581 openssl cms -verify -inform PEM -in signature.pem -content content.txt 582 583alternatively you can base64 decode the signature and use 584 585 openssl cms -verify -inform DER -in signature.der -content content.txt 586 587Create an encrypted message using 128 bit Camellia: 588 589 openssl cms -encrypt -in plain.txt -camellia128 -out mail.msg cert.pem 590 591Add a signer to an existing message: 592 593 openssl cms -resign -in mail.msg -signer newsign.pem -out mail2.msg 594 595=head1 BUGS 596 597The MIME parser isn't very clever: it seems to handle most messages that I've 598thrown at it but it may choke on others. 599 600The code currently will only write out the signer's certificate to a file: if 601the signer has a separate encryption certificate this must be manually 602extracted. There should be some heuristic that determines the correct 603encryption certificate. 604 605Ideally a database should be maintained of a certificates for each email 606address. 607 608The code doesn't currently take note of the permitted symmetric encryption 609algorithms as supplied in the SMIMECapabilities signed attribute. this means the 610user has to manually include the correct encryption algorithm. It should store 611the list of permitted ciphers in a database and only use those. 612 613No revocation checking is done on the signer's certificate. 614 615=head1 HISTORY 616 617The use of multiple B<-signer> options and the B<-resign> command were first 618added in OpenSSL 1.0.0 619 620 621The -no_alt_chains options was first added to OpenSSL 1.0.1n and 1.0.2b. 622 623=cut 624