1180750SdesThis describes the protocol used by OpenSSH's ssh-agent. 2180750Sdes 3180750SdesOpenSSH's agent supports managing keys for the standard SSH protocol 4180750Sdes2 as well as the legacy SSH protocol 1. Support for these key types 5180750Sdesis almost completely disjoint - in all but a few cases, operations on 6180750Sdesprotocol 2 keys cannot see or affect protocol 1 keys and vice-versa. 7180750Sdes 8180750SdesProtocol 1 and protocol 2 keys are separated because of the differing 9180750Sdescryptographic usage: protocol 1 private RSA keys are used to decrypt 10180750Sdeschallenges that were encrypted with the corresponding public key, 11180750Sdeswhereas protocol 2 RSA private keys are used to sign challenges with 12180750Sdesa private key for verification with the corresponding public key. It 13180750Sdesis considered unsound practice to use the same key for signing and 14180750Sdesencryption. 15180750Sdes 16180750SdesWith a couple of exceptions, the protocol message names used in this 17180750Sdesdocument indicate which type of key the message relates to. SSH_* 18180750Sdesmessages refer to protocol 1 keys only. SSH2_* messages refer to 19180750Sdesprotocol 2 keys. Furthermore, the names also indicate whether the 20180750Sdesmessage is a request to the agent (*_AGENTC_*) or a reply from the 21180750Sdesagent (*_AGENT_*). Section 3 below contains the mapping of the 22180750Sdesprotocol message names to their integer values. 23180750Sdes 24180750Sdes1. Data types 25180750Sdes 26180750SdesBecause of support for legacy SSH protocol 1 keys, OpenSSH's agent 27180750Sdesprotocol makes use of some data types not defined in RFC 4251. 28180750Sdes 29180750Sdes1.1 uint16 30180750Sdes 31180750SdesThe "uint16" data type is a simple MSB-first 16 bit unsigned integer 32180750Sdesencoded in two bytes. 33180750Sdes 34180750Sdes1.2 mpint1 35180750Sdes 36180750SdesThe "mpint1" type represents an arbitrary precision integer (bignum). 37180750SdesIts format is as follows: 38180750Sdes 39180750Sdes uint16 bits 40180750Sdes byte[(bits + 7) / 8] bignum 41180750Sdes 42180750Sdes"bignum" contains an unsigned arbitrary precision integer encoded as 43180750Sdeseight bits per byte in big-endian (MSB first) format. 44180750Sdes 45180750SdesNote the difference between the "mpint1" encoding and the "mpint" 46180750Sdesencoding defined in RFC 4251. Also note that the length of the encoded 47180750Sdesinteger is specified in bits, not bytes and that the byte length of 48180750Sdesthe integer must be calculated by rounding up the number of bits to the 49180750Sdesnearest eight. 50180750Sdes 51180750Sdes2. Protocol Messages 52180750Sdes 53180750SdesAll protocol messages are prefixed with their length in bytes, encoded 54180750Sdesas a 32 bit unsigned integer. Specifically: 55180750Sdes 56180750Sdes uint32 message_length 57180750Sdes byte[message_length] message 58180750Sdes 59180750SdesThe following message descriptions refer only to the content the 60180750Sdes"message" field. 61180750Sdes 62180750Sdes2.1 Generic server responses 63180750Sdes 64180750SdesThe following generic messages may be sent by the server in response to 65180750Sdesrequests from the client. On success the agent may reply either with: 66180750Sdes 67180750Sdes byte SSH_AGENT_SUCCESS 68180750Sdes 69180750Sdesor a request-specific success message. 70180750Sdes 71180750SdesOn failure, the agent may reply with: 72180750Sdes 73180750Sdes byte SSH_AGENT_FAILURE 74180750Sdes 75180750SdesSSH_AGENT_FAILURE messages are also sent in reply to unknown request 76180750Sdestypes. 77180750Sdes 78180750Sdes2.2 Adding keys to the agent 79180750Sdes 80180750SdesKeys are added to the agent using the SSH_AGENTC_ADD_RSA_IDENTITY and 81180750SdesSSH2_AGENTC_ADD_IDENTITY requests for protocol 1 and protocol 2 keys 82180750Sdesrespectively. 83180750Sdes 84180750SdesTwo variants of these requests are SSH_AGENTC_ADD_RSA_ID_CONSTRAINED 85180750Sdesand SSH2_AGENTC_ADD_ID_CONSTRAINED - these add keys with optional 86180750Sdes"constraints" on their usage. 87180750Sdes 88180750SdesOpenSSH may be built with support for keys hosted on a smartcard 89180750Sdesor other hardware security module. These keys may be added 90180750Sdesto the agent using the SSH_AGENTC_ADD_SMARTCARD_KEY and 91180750SdesSSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED requests. 92180750Sdes 93180750Sdes2.2.1 Key constraints 94180750Sdes 95180750SdesThe OpenSSH agent supports some basic optional constraints on key usage. 96180750SdesAt present there are two constraints defined. 97180750Sdes 98180750SdesThe first constraint limits the validity duration of a key. It is 99180750Sdesencoded as: 100180750Sdes 101180750Sdes byte SSH_AGENT_CONSTRAIN_LIFETIME 102180750Sdes uint32 seconds 103180750Sdes 104180750SdesWhere "seconds" contains the number of seconds that the key shall remain 105180750Sdesvalid measured from the moment that the agent receives it. After the 106180750Sdesvalidity period has expired, OpenSSH's agent will erase these keys from 107180750Sdesmemory. 108180750Sdes 109180750SdesThe second constraint requires the agent to seek explicit user 110180750Sdesconfirmation before performing private key operations with the loaded 111180750Sdeskey. This constraint is encoded as: 112180750Sdes 113180750Sdes byte SSH_AGENT_CONSTRAIN_CONFIRM 114180750Sdes 115180750SdesZero or more constraints may be specified when adding a key with one 116180750Sdesof the *_CONSTRAINED requests. Multiple constraints are appended 117180750Sdesconsecutively to the end of the request: 118180750Sdes 119180750Sdes byte constraint1_type 120180750Sdes .... constraint1_data 121180750Sdes byte constraint2_type 122180750Sdes .... constraint2_data 123180750Sdes .... 124180750Sdes byte constraintN_type 125180750Sdes .... constraintN_data 126180750Sdes 127180750SdesSuch a sequence of zero or more constraints will be referred to below 128180750Sdesas "constraint[]". Agents may determine whether there are constraints 129180750Sdesby checking whether additional data exists in the "add key" request 130180750Sdesafter the key data itself. OpenSSH will refuse to add a key if it 131180750Sdescontains unknown constraints. 132180750Sdes 133180750Sdes2.2.2 Add protocol 1 key 134180750Sdes 135180750SdesA client may add a protocol 1 key to an agent with the following 136180750Sdesrequest: 137180750Sdes 138180750Sdes byte SSH_AGENTC_ADD_RSA_IDENTITY or 139180750Sdes SSH_AGENTC_ADD_RSA_ID_CONSTRAINED 140180750Sdes uint32 ignored 141180750Sdes mpint1 rsa_n 142180750Sdes mpint1 rsa_e 143180750Sdes mpint1 rsa_d 144180750Sdes mpint1 rsa_iqmp 145180750Sdes mpint1 rsa_q 146180750Sdes mpint1 rsa_p 147180750Sdes string key_comment 148180750Sdes constraint[] key_constraints 149180750Sdes 150180750SdesNote that there is some redundancy in the key parameters; a key could be 151180750Sdesfully specified using just rsa_q, rsa_p and rsa_e at the cost of extra 152180750Sdescomputation. 153180750Sdes 154180750Sdes"key_constraints" may only be present if the request type is 155251135SdesSSH_AGENTC_ADD_RSA_ID_CONSTRAINED. 156180750Sdes 157180750SdesThe agent will reply with a SSH_AGENT_SUCCESS if the key has been 158180750Sdessuccessfully added or a SSH_AGENT_FAILURE if an error occurred. 159180750Sdes 160180750Sdes2.2.3 Add protocol 2 key 161180750Sdes 162221420SdesThe OpenSSH agent supports DSA, ECDSA and RSA keys for protocol 2. DSA 163221420Sdeskeys may be added using the following request 164180750Sdes 165180750Sdes byte SSH2_AGENTC_ADD_IDENTITY or 166180750Sdes SSH2_AGENTC_ADD_ID_CONSTRAINED 167180750Sdes string "ssh-dss" 168180750Sdes mpint dsa_p 169180750Sdes mpint dsa_q 170180750Sdes mpint dsa_g 171180750Sdes mpint dsa_public_key 172180750Sdes mpint dsa_private_key 173180750Sdes string key_comment 174180750Sdes constraint[] key_constraints 175180750Sdes 176204917SdesDSA certificates may be added with: 177204917Sdes byte SSH2_AGENTC_ADD_IDENTITY or 178204917Sdes SSH2_AGENTC_ADD_ID_CONSTRAINED 179204917Sdes string "ssh-dss-cert-v00@openssh.com" 180204917Sdes string certificate 181204917Sdes mpint dsa_private_key 182204917Sdes string key_comment 183204917Sdes constraint[] key_constraints 184204917Sdes 185221420SdesECDSA keys may be added using the following request 186221420Sdes 187221420Sdes byte SSH2_AGENTC_ADD_IDENTITY or 188221420Sdes SSH2_AGENTC_ADD_ID_CONSTRAINED 189221420Sdes string "ecdsa-sha2-nistp256" | 190221420Sdes "ecdsa-sha2-nistp384" | 191221420Sdes "ecdsa-sha2-nistp521" 192221420Sdes string ecdsa_curve_name 193221420Sdes string ecdsa_public_key 194221420Sdes mpint ecdsa_private 195221420Sdes string key_comment 196221420Sdes constraint[] key_constraints 197221420Sdes 198221420SdesECDSA certificates may be added with: 199221420Sdes byte SSH2_AGENTC_ADD_IDENTITY or 200221420Sdes SSH2_AGENTC_ADD_ID_CONSTRAINED 201221420Sdes string "ecdsa-sha2-nistp256-cert-v01@openssh.com" | 202221420Sdes "ecdsa-sha2-nistp384-cert-v01@openssh.com" | 203221420Sdes "ecdsa-sha2-nistp521-cert-v01@openssh.com" 204221420Sdes string certificate 205221420Sdes mpint ecdsa_private_key 206221420Sdes string key_comment 207221420Sdes constraint[] key_constraints 208221420Sdes 209180750SdesRSA keys may be added with this request: 210180750Sdes 211180750Sdes byte SSH2_AGENTC_ADD_IDENTITY or 212180750Sdes SSH2_AGENTC_ADD_ID_CONSTRAINED 213180750Sdes string "ssh-rsa" 214180750Sdes mpint rsa_n 215180750Sdes mpint rsa_e 216180750Sdes mpint rsa_d 217180750Sdes mpint rsa_iqmp 218180750Sdes mpint rsa_p 219180750Sdes mpint rsa_q 220180750Sdes string key_comment 221180750Sdes constraint[] key_constraints 222180750Sdes 223204917SdesRSA certificates may be added with this request: 224204917Sdes 225204917Sdes byte SSH2_AGENTC_ADD_IDENTITY or 226204917Sdes SSH2_AGENTC_ADD_ID_CONSTRAINED 227204917Sdes string "ssh-rsa-cert-v00@openssh.com" 228204917Sdes string certificate 229204917Sdes mpint rsa_d 230204917Sdes mpint rsa_iqmp 231204917Sdes mpint rsa_p 232204917Sdes mpint rsa_q 233204917Sdes string key_comment 234204917Sdes constraint[] key_constraints 235204917Sdes 236180750SdesNote that the 'rsa_p' and 'rsa_q' parameters are sent in the reverse 237180750Sdesorder to the protocol 1 add keys message. As with the corresponding 238180750Sdesprotocol 1 "add key" request, the private key is overspecified to avoid 239180750Sdesredundant processing. 240180750Sdes 241221420SdesFor DSA, ECDSA and RSA key add requests, "key_constraints" may only be 242180750Sdespresent if the request type is SSH2_AGENTC_ADD_ID_CONSTRAINED. 243180750Sdes 244180750SdesThe agent will reply with a SSH_AGENT_SUCCESS if the key has been 245180750Sdessuccessfully added or a SSH_AGENT_FAILURE if an error occurred. 246180750Sdes 247180750Sdes2.2.4 Loading keys from a smartcard 248180750Sdes 249180750SdesThe OpenSSH agent may have optional smartcard support built in to it. If 250180750Sdesso, it supports an operation to load keys from a smartcard. Technically, 251180750Sdesonly the public components of the keys are loaded into the agent so 252180750Sdesthis operation really arranges for future private key operations to be 253180750Sdesdelegated to the smartcard. 254180750Sdes 255180750Sdes byte SSH_AGENTC_ADD_SMARTCARD_KEY or 256180750Sdes SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED 257180750Sdes string reader_id 258180750Sdes string pin 259180750Sdes constraint[] key_constraints 260180750Sdes 261180750Sdes"reader_id" is an identifier to a smartcard reader and "pin" 262180750Sdesis a PIN or passphrase used to unlock the private key(s) on the 263180750Sdesdevice. "key_constraints" may only be present if the request type is 264180750SdesSSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED. 265180750Sdes 266180750SdesThis operation may load all SSH keys that are unlocked using the 267180750Sdes"pin" on the specified reader. The type of key loaded (protocol 1 268180750Sdesor protocol 2) will be specified by the smartcard itself, it is not 269180750Sdesclient-specified. 270180750Sdes 271180750SdesThe agent will reply with a SSH_AGENT_SUCCESS if one or more keys have 272180750Sdesbeen successfully loaded or a SSH_AGENT_FAILURE if an error occurred. 273180750SdesThe agent will also return SSH_AGENT_FAILURE if it does not support 274180750Sdessmartcards. 275180750Sdes 276180750Sdes2.3 Removing multiple keys 277180750Sdes 278180750SdesA client may request that an agent delete all protocol 1 keys using the 279180750Sdesfollowing request: 280180750Sdes 281180750Sdes byte SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES 282180750Sdes 283180750SdesThis message requests the deletion of all protocol 2 keys: 284180750Sdes 285180750Sdes byte SSH2_AGENTC_REMOVE_ALL_IDENTITIES 286180750Sdes 287180750SdesOn success, the agent will delete all keys of the requested type and 288180750Sdesreply with a SSH_AGENT_SUCCESS message. If an error occurred, the agent 289180750Sdeswill reply with SSH_AGENT_FAILURE. 290180750Sdes 291180750SdesNote that, to delete all keys (both protocol 1 and 2), a client 292180750Sdesmust send both a SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES and a 293180750SdesSSH2_AGENTC_REMOVE_ALL_IDENTITIES request. 294180750Sdes 295180750Sdes2.4 Removing specific keys 296180750Sdes 297180750Sdes2.4.1 Removing a protocol 1 key 298180750Sdes 299180750SdesRemoval of a protocol 1 key may be requested with the following message: 300180750Sdes 301180750Sdes byte SSH_AGENTC_REMOVE_RSA_IDENTITY 302180750Sdes uint32 key_bits 303180750Sdes mpint1 rsa_e 304180750Sdes mpint1 rsa_n 305180750Sdes 306180750SdesNote that key_bits is strictly redundant, as it may be inferred by the 307180750Sdeslength of rsa_n. 308180750Sdes 309180750SdesThe agent will delete any private key matching the specified public key 310180750Sdesand return SSH_AGENT_SUCCESS. If no such key was found, the agent will 311180750Sdesreturn SSH_AGENT_FAILURE. 312180750Sdes 313180750Sdes2.4.2 Removing a protocol 2 key 314180750Sdes 315180750SdesProtocol 2 keys may be removed with the following request: 316180750Sdes 317180750Sdes byte SSH2_AGENTC_REMOVE_IDENTITY 318180750Sdes string key_blob 319180750Sdes 320180750SdesWhere "key_blob" is encoded as per RFC 4253 section 6.6 "Public Key 321221420SdesAlgorithms" for any of the supported protocol 2 key types. 322180750Sdes 323180750SdesThe agent will delete any private key matching the specified public key 324180750Sdesand return SSH_AGENT_SUCCESS. If no such key was found, the agent will 325180750Sdesreturn SSH_AGENT_FAILURE. 326180750Sdes 327180750Sdes2.4.3 Removing keys loaded from a smartcard 328180750Sdes 329180750SdesA client may request that a server remove one or more smartcard-hosted 330180750Sdeskeys using this message: 331180750Sdes 332180750Sdes byte SSH_AGENTC_REMOVE_SMARTCARD_KEY 333180750Sdes string reader_id 334180750Sdes string pin 335180750Sdes 336180750Sdes"reader_id" the an identifier to a smartcard reader and "pin" is a PIN 337180750Sdesor passphrase used to unlock the private key(s) on the device. 338180750Sdes 339180750SdesWhen this message is received, and if the agent supports 340180750Sdessmartcard-hosted keys, it will delete all keys that are hosted on the 341180750Sdesspecified smartcard that may be accessed with the given "pin". 342180750Sdes 343180750SdesThe agent will reply with a SSH_AGENT_SUCCESS if one or more keys have 344180750Sdesbeen successfully removed or a SSH_AGENT_FAILURE if an error occurred. 345180750SdesThe agent will also return SSH_AGENT_FAILURE if it does not support 346180750Sdessmartcards. 347180750Sdes 348180750Sdes2.5 Requesting a list of known keys 349180750Sdes 350180750SdesAn agent may be requested to list which keys it holds. Different 351180750Sdesrequests exist for protocol 1 and protocol 2 keys. 352180750Sdes 353180750Sdes2.5.1 Requesting a list of protocol 1 keys 354180750Sdes 355180750SdesTo request a list of protocol 1 keys that are held in the agent, a 356180750Sdesclient may send the following message: 357180750Sdes 358180750Sdes byte SSH_AGENTC_REQUEST_RSA_IDENTITIES 359180750Sdes 360180750SdesThe agent will reply with the following message: 361180750Sdes 362180750Sdes byte SSH_AGENT_RSA_IDENTITIES_ANSWER 363180750Sdes uint32 num_keys 364180750Sdes 365180750SdesFollowed by zero or more consecutive keys, encoded as: 366180750Sdes 367180750Sdes uint32 bits 368180750Sdes mpint1 rsa_e 369180750Sdes mpint1 rsa_n 370180750Sdes string key_comment 371180750Sdes 372180750Sdes2.5.2 Requesting a list of protocol 2 keys 373180750Sdes 374180750SdesA client may send the following message to request a list of 375180750Sdesprotocol 2 keys that are stored in the agent: 376180750Sdes 377180750Sdes byte SSH2_AGENTC_REQUEST_IDENTITIES 378180750Sdes 379180750SdesThe agent will reply with the following message header: 380180750Sdes 381180750Sdes byte SSH2_AGENT_IDENTITIES_ANSWER 382180750Sdes uint32 num_keys 383180750Sdes 384180750SdesFollowed by zero or more consecutive keys, encoded as: 385180750Sdes 386180750Sdes string key_blob 387180750Sdes string key_comment 388180750Sdes 389180750SdesWhere "key_blob" is encoded as per RFC 4253 section 6.6 "Public Key 390221420SdesAlgorithms" for any of the supported protocol 2 key types. 391180750Sdes 392180750Sdes2.6 Private key operations 393180750Sdes 394180750SdesThe purpose of the agent is to perform private key operations, such as 395180750Sdessigning and encryption without requiring a passphrase to unlock the 396180750Sdeskey and without allowing the private key itself to be exposed. There 397180750Sdesare separate requests for the protocol 1 and protocol 2 private key 398180750Sdesoperations. 399180750Sdes 400180750Sdes2.6.1 Protocol 1 private key challenge 401180750Sdes 402180750SdesThe private key operation used in version 1 of the SSH protocol is 403180750Sdesdecrypting a challenge that has been encrypted with a public key. 404180750SdesIt may be requested using this message: 405180750Sdes 406180750Sdes byte SSH_AGENTC_RSA_CHALLENGE 407180750Sdes uint32 ignored 408180750Sdes mpint1 rsa_e 409180750Sdes mpint1 rsa_n 410180750Sdes mpint1 encrypted_challenge 411180750Sdes byte[16] session_id 412180750Sdes uint32 response_type /* must be 1 */ 413180750Sdes 414180750Sdes"rsa_e" and "rsa_n" are used to identify which private key to use. 415180750Sdes"encrypted_challenge" is a challenge blob that has (presumably) 416180750Sdesbeen encrypted with the public key and must be in the range 417180750Sdes1 <= encrypted_challenge < 2^256. "session_id" is the SSH protocol 1 418180750Sdessession ID (computed from the server host key, the server semi-ephemeral 419180750Sdeskey and the session cookie). 420180750Sdes 421180750Sdes"ignored" and "response_type" exist for compatibility with legacy 422180750Sdesimplementations. "response_type" must be equal to 1; other response 423180750Sdestypes are not supported. 424180750Sdes 425180750SdesOn receiving this request, the server decrypts the "encrypted_challenge" 426180750Sdesusing the private key matching the supplied (rsa_e, rsa_n) values. For 427180750Sdesthe response derivation, the decrypted challenge is represented as an 428180750Sdesunsigned, big-endian integer encoded in a 32 byte buffer (i.e. values 429180750Sdessmaller than 2^248 will have leading 0 bytes). 430180750Sdes 431180750SdesThe response value is then calculated as: 432180750Sdes 433180750Sdes response = MD5(decrypted_challenge || session_id) 434180750Sdes 435180750Sdesand returned in the following message 436180750Sdes 437180750Sdes byte SSH_AGENT_RSA_RESPONSE 438180750Sdes byte[16] response 439180750Sdes 440180750SdesIf the agent cannot find the key specified by the supplied (rsa_e, 441180750Sdesrsa_n) then it will return SSH_AGENT_FAILURE. 442180750Sdes 443180750Sdes2.6.2 Protocol 2 private key signature request 444180750Sdes 445180750SdesA client may use the following message to request signing of data using 446180750Sdesa protocol 2 key: 447180750Sdes 448180750Sdes byte SSH2_AGENTC_SIGN_REQUEST 449180750Sdes string key_blob 450180750Sdes string data 451180750Sdes uint32 flags 452180750Sdes 453180750SdesWhere "key_blob" is encoded as per RFC 4253 section 6.6 "Public Key 454221420SdesAlgorithms" for any of the supported protocol 2 key types. "flags" is 455221420Sdesa bit-mask, but at present only one possible value is defined (see below 456221420Sdesfor its meaning): 457180750Sdes 458180750Sdes SSH_AGENT_OLD_SIGNATURE 1 459180750Sdes 460180750SdesUpon receiving this request, the agent will look up the private key that 461180750Sdescorresponds to the public key contained in key_blob. It will use this 462180750Sdesprivate key to sign the "data" and produce a signature blob using the 463180750Sdeskey type-specific method described in RFC 4253 section 6.6 "Public Key 464180750SdesAlgorithms". 465180750Sdes 466180750SdesAn exception to this is for "ssh-dss" keys where the "flags" word 467180750Sdescontains the value SSH_AGENT_OLD_SIGNATURE. In this case, a legacy 468180750Sdessignature encoding is used in lieu of the standard one. In this case, 469180750Sdesthe DSA signature blob is encoded as: 470180750Sdes 471180750Sdes byte[40] signature 472180750Sdes 473180750SdesThe signature will be returned in the response message: 474180750Sdes 475180750Sdes byte SSH2_AGENT_SIGN_RESPONSE 476180750Sdes string signature_blob 477180750Sdes 478180750SdesIf the agent cannot find the key specified by the supplied key_blob then 479180750Sdesit will return SSH_AGENT_FAILURE. 480180750Sdes 481180750Sdes2.7 Locking or unlocking an agent 482180750Sdes 483180750SdesThe agent supports temporary locking with a passphrase to suspend 484180750Sdesprocessing of sensitive operations until it has been unlocked with the 485180750Sdessame passphrase. To lock an agent, a client send the following request: 486180750Sdes 487180750Sdes byte SSH_AGENTC_LOCK 488180750Sdes string passphrase 489180750Sdes 490180750SdesUpon receipt of this message and if the agent is not already locked, 491180750Sdesit will suspend processing requests and return a SSH_AGENT_SUCCESS 492180750Sdesreply. If the agent is already locked, it will return SSH_AGENT_FAILURE. 493180750Sdes 494180750SdesWhile locked, the agent will refuse all requests except 495180750SdesSSH_AGENTC_UNLOCK, SSH_AGENTC_REQUEST_RSA_IDENTITIES and 496180750SdesSSH2_AGENTC_REQUEST_IDENTITIES. The "request identities" requests are 497180750Sdestreated specially by a locked agent: it will always return an empty list 498180750Sdesof keys. 499180750Sdes 500180750SdesTo unlock an agent, a client may request: 501180750Sdes 502180750Sdes byte SSH_AGENTC_UNLOCK 503180750Sdes string passphrase 504180750Sdes 505180750SdesIf the passphrase matches and the agent is locked, then it will resume 506180750Sdesprocessing all requests and return SSH_AGENT_SUCCESS. If the agent 507180750Sdesis not locked or the passphrase does not match then it will return 508180750SdesSSH_AGENT_FAILURE. 509180750Sdes 510180750SdesLocking and unlocking affects both protocol 1 and protocol 2 keys. 511180750Sdes 512180750Sdes3. Protocol message numbers 513180750Sdes 514180750Sdes3.1 Requests from client to agent for protocol 1 key operations 515180750Sdes 516180750Sdes SSH_AGENTC_REQUEST_RSA_IDENTITIES 1 517180750Sdes SSH_AGENTC_RSA_CHALLENGE 3 518180750Sdes SSH_AGENTC_ADD_RSA_IDENTITY 7 519180750Sdes SSH_AGENTC_REMOVE_RSA_IDENTITY 8 520180750Sdes SSH_AGENTC_REMOVE_ALL_RSA_IDENTITIES 9 521180750Sdes SSH_AGENTC_ADD_RSA_ID_CONSTRAINED 24 522180750Sdes 523180750Sdes3.2 Requests from client to agent for protocol 2 key operations 524180750Sdes 525180750Sdes SSH2_AGENTC_REQUEST_IDENTITIES 11 526180750Sdes SSH2_AGENTC_SIGN_REQUEST 13 527180750Sdes SSH2_AGENTC_ADD_IDENTITY 17 528180750Sdes SSH2_AGENTC_REMOVE_IDENTITY 18 529180750Sdes SSH2_AGENTC_REMOVE_ALL_IDENTITIES 19 530180750Sdes SSH2_AGENTC_ADD_ID_CONSTRAINED 25 531180750Sdes 532180750Sdes3.3 Key-type independent requests from client to agent 533180750Sdes 534180750Sdes SSH_AGENTC_ADD_SMARTCARD_KEY 20 535180750Sdes SSH_AGENTC_REMOVE_SMARTCARD_KEY 21 536180750Sdes SSH_AGENTC_LOCK 22 537180750Sdes SSH_AGENTC_UNLOCK 23 538180750Sdes SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED 26 539180750Sdes 540180750Sdes3.4 Generic replies from agent to client 541180750Sdes 542180750Sdes SSH_AGENT_FAILURE 5 543180750Sdes SSH_AGENT_SUCCESS 6 544180750Sdes 545180750Sdes3.5 Replies from agent to client for protocol 1 key operations 546180750Sdes 547180750Sdes SSH_AGENT_RSA_IDENTITIES_ANSWER 2 548180750Sdes SSH_AGENT_RSA_RESPONSE 4 549180750Sdes 550180750Sdes3.6 Replies from agent to client for protocol 2 key operations 551180750Sdes 552180750Sdes SSH2_AGENT_IDENTITIES_ANSWER 12 553180750Sdes SSH2_AGENT_SIGN_RESPONSE 14 554180750Sdes 555180750Sdes3.7 Key constraint identifiers 556180750Sdes 557180750Sdes SSH_AGENT_CONSTRAIN_LIFETIME 1 558180750Sdes SSH_AGENT_CONSTRAIN_CONFIRM 2 559180750Sdes 560251135Sdes$OpenBSD: PROTOCOL.agent,v 1.7 2013/01/02 00:33:49 djm Exp $ 561