cms.pod revision 269686
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<-md digest>] 39[B<-[cipher]>] 40[B<-nointern>] 41[B<-no_signer_cert_verify>] 42[B<-nocerts>] 43[B<-noattr>] 44[B<-nosmimecap>] 45[B<-binary>] 46[B<-nodetach>] 47[B<-certfile file>] 48[B<-certsout file>] 49[B<-signer file>] 50[B<-recip file>] 51[B<-keyid>] 52[B<-receipt_request_all -receipt_request_first>] 53[B<-receipt_request_from emailaddress>] 54[B<-receipt_request_to emailaddress>] 55[B<-receipt_request_print>] 56[B<-secretkey key>] 57[B<-secretkeyid id>] 58[B<-econtent_type type>] 59[B<-inkey file>] 60[B<-passin arg>] 61[B<-rand file(s)>] 62[B<cert.pem...>] 63[B<-to addr>] 64[B<-from addr>] 65[B<-subject subj>] 66[cert.pem]... 67 68=head1 DESCRIPTION 69 70The B<cms> command handles S/MIME v3.1 mail. It can encrypt, decrypt, sign and 71verify, compress and uncompress S/MIME messages. 72 73=head1 COMMAND OPTIONS 74 75There are fourteen operation options that set the type of operation to be 76performed. The meaning of the other options varies according to the operation 77type. 78 79=over 4 80 81=item B<-encrypt> 82 83encrypt mail for the given recipient certificates. Input file is the message 84to be encrypted. The output file is the encrypted mail in MIME format. The 85actual CMS type is <B>EnvelopedData<B>. 86 87=item B<-decrypt> 88 89decrypt mail using the supplied certificate and private key. Expects an 90encrypted mail message in MIME format for the input file. The decrypted mail 91is written to the output file. 92 93=item B<-debug_decrypt> 94 95this option sets the B<CMS_DEBUG_DECRYPT> flag. This option should be used 96with caution: see the notes section below. 97 98=item B<-sign> 99 100sign mail using the supplied certificate and private key. Input file is 101the message to be signed. The signed message in MIME format is written 102to the output file. 103 104=item B<-verify> 105 106verify signed mail. Expects a signed mail message on input and outputs 107the signed data. Both clear text and opaque signing is supported. 108 109=item B<-cmsout> 110 111takes an input message and writes out a PEM encoded CMS structure. 112 113=item B<-resign> 114 115resign a message: take an existing message and one or more new signers. 116 117=item B<-data_create> 118 119Create a CMS B<Data> type. 120 121=item B<-data_out> 122 123B<Data> type and output the content. 124 125=item B<-digest_create> 126 127Create a CMS B<DigestedData> type. 128 129=item B<-digest_verify> 130 131Verify a CMS B<DigestedData> type and output the content. 132 133=item B<-compress> 134 135Create a CMS B<CompressedData> type. OpenSSL must be compiled with B<zlib> 136support for this option to work, otherwise it will output an error. 137 138=item B<-uncompress> 139 140Uncompress a CMS B<CompressedData> type and output the content. OpenSSL must be 141compiled with B<zlib> support for this option to work, otherwise it will 142output an error. 143 144=item B<-EncryptedData_encrypt> 145 146Encrypt content using supplied symmetric key and algorithm using a CMS 147B<EncrytedData> type and output the content. 148 149=item B<-sign_receipt> 150 151Generate and output a signed receipt for the supplied message. The input 152message B<must> contain a signed receipt request. Functionality is otherwise 153similar to the B<-sign> operation. 154 155=item B<-verify_receipt receipt> 156 157Verify a signed receipt in filename B<receipt>. The input message B<must> 158contain the original receipt request. Functionality is otherwise similar 159to the B<-verify> operation. 160 161=item B<-in filename> 162 163the input message to be encrypted or signed or the message to be decrypted 164or verified. 165 166=item B<-inform SMIME|PEM|DER> 167 168this specifies the input format for the CMS structure. The default 169is B<SMIME> which reads an S/MIME format message. B<PEM> and B<DER> 170format change this to expect PEM and DER format CMS structures 171instead. This currently only affects the input format of the CMS 172structure, if no CMS structure is being input (for example with 173B<-encrypt> or B<-sign>) this option has no effect. 174 175=item B<-rctform SMIME|PEM|DER> 176 177specify the format for a signed receipt for use with the B<-receipt_verify> 178operation. 179 180=item B<-out filename> 181 182the message text that has been decrypted or verified or the output MIME 183format message that has been signed or verified. 184 185=item B<-outform SMIME|PEM|DER> 186 187this specifies the output format for the CMS structure. The default 188is B<SMIME> which writes an S/MIME format message. B<PEM> and B<DER> 189format change this to write PEM and DER format CMS structures 190instead. This currently only affects the output format of the CMS 191structure, if no CMS structure is being output (for example with 192B<-verify> or B<-decrypt>) this option has no effect. 193 194=item B<-stream -indef -noindef> 195 196the B<-stream> and B<-indef> options are equivalent and enable streaming I/O 197for encoding operations. This permits single pass processing of data without 198the need to hold the entire contents in memory, potentially supporting very 199large files. Streaming is automatically set for S/MIME signing with detached 200data if the output format is B<SMIME> it is currently off by default for all 201other operations. 202 203=item B<-noindef> 204 205disable streaming I/O where it would produce and indefinite length constructed 206encoding. This option currently has no effect. In future streaming will be 207enabled by default on all relevant operations and this option will disable it. 208 209=item B<-content filename> 210 211This specifies a file containing the detached content, this is only 212useful with the B<-verify> command. This is only usable if the CMS 213structure is using the detached signature form where the content is 214not included. This option will override any content if the input format 215is S/MIME and it uses the multipart/signed MIME content type. 216 217=item B<-text> 218 219this option adds plain text (text/plain) MIME headers to the supplied 220message if encrypting or signing. If decrypting or verifying it strips 221off text headers: if the decrypted or verified message is not of MIME 222type text/plain then an error occurs. 223 224=item B<-noout> 225 226for the B<-cmsout> operation do not output the parsed CMS structure. This 227is useful when combined with the B<-print> option or if the syntax of the CMS 228structure is being checked. 229 230=item B<-print> 231 232for the B<-cmsout> operation print out all fields of the CMS structure. This 233is mainly useful for testing purposes. 234 235=item B<-CAfile file> 236 237a file containing trusted CA certificates, only used with B<-verify>. 238 239=item B<-CApath dir> 240 241a directory containing trusted CA certificates, only used with 242B<-verify>. This directory must be a standard certificate directory: that 243is a hash of each subject name (using B<x509 -hash>) should be linked 244to each certificate. 245 246=item B<-md digest> 247 248digest algorithm to use when signing or resigning. If not present then the 249default digest algorithm for the signing key will be used (usually SHA1). 250 251=item B<-[cipher]> 252 253the encryption algorithm to use. For example triple DES (168 bits) - B<-des3> 254or 256 bit AES - B<-aes256>. Any standard algorithm name (as used by the 255EVP_get_cipherbyname() function) can also be used preceded by a dash, for 256example B<-aes_128_cbc>. See L<B<enc>|enc(1)> for a list of ciphers 257supported by your version of OpenSSL. 258 259If not specified triple DES is used. Only used with B<-encrypt> and 260B<-EncryptedData_create> commands. 261 262=item B<-nointern> 263 264when verifying a message normally certificates (if any) included in 265the message are searched for the signing certificate. With this option 266only the certificates specified in the B<-certfile> option are used. 267The supplied certificates can still be used as untrusted CAs however. 268 269=item B<-no_signer_cert_verify> 270 271do not verify the signers certificate of a signed message. 272 273=item B<-nocerts> 274 275when signing a message the signer's certificate is normally included 276with this option it is excluded. This will reduce the size of the 277signed message but the verifier must have a copy of the signers certificate 278available locally (passed using the B<-certfile> option for example). 279 280=item B<-noattr> 281 282normally when a message is signed a set of attributes are included which 283include the signing time and supported symmetric algorithms. With this 284option they are not included. 285 286=item B<-nosmimecap> 287 288exclude the list of supported algorithms from signed attributes, other options 289such as signing time and content type are still included. 290 291=item B<-binary> 292 293normally the input message is converted to "canonical" format which is 294effectively using CR and LF as end of line: as required by the S/MIME 295specification. When this option is present no translation occurs. This 296is useful when handling binary data which may not be in MIME format. 297 298=item B<-nodetach> 299 300when signing a message use opaque signing: this form is more resistant 301to translation by mail relays but it cannot be read by mail agents that 302do not support S/MIME. Without this option cleartext signing with 303the MIME type multipart/signed is used. 304 305=item B<-certfile file> 306 307allows additional certificates to be specified. When signing these will 308be included with the message. When verifying these will be searched for 309the signers certificates. The certificates should be in PEM format. 310 311=item B<-certsout file> 312 313any certificates contained in the message are written to B<file>. 314 315=item B<-signer file> 316 317a signing certificate when signing or resigning a message, this option can be 318used multiple times if more than one signer is required. If a message is being 319verified then the signers certificates will be written to this file if the 320verification was successful. 321 322=item B<-recip file> 323 324the recipients certificate when decrypting a message. This certificate 325must match one of the recipients of the message or an error occurs. 326 327=item B<-keyid> 328 329use subject key identifier to identify certificates instead of issuer name and 330serial number. The supplied certificate B<must> include a subject key 331identifier extension. Supported by B<-sign> and B<-encrypt> options. 332 333=item B<-receipt_request_all -receipt_request_first> 334 335for B<-sign> option include a signed receipt request. Indicate requests should 336be provided by all receipient or first tier recipients (those mailed directly 337and not from a mailing list). Ignored it B<-receipt_request_from> is included. 338 339=item B<-receipt_request_from emailaddress> 340 341for B<-sign> option include a signed receipt request. Add an explicit email 342address where receipts should be supplied. 343 344=item B<-receipt_request_to emailaddress> 345 346Add an explicit email address where signed receipts should be sent to. This 347option B<must> but supplied if a signed receipt it requested. 348 349=item B<-receipt_request_print> 350 351For the B<-verify> operation print out the contents of any signed receipt 352requests. 353 354=item B<-secretkey key> 355 356specify symmetric key to use. The key must be supplied in hex format and be 357consistent with the algorithm used. Supported by the B<-EncryptedData_encrypt> 358B<-EncrryptedData_decrypt>, B<-encrypt> and B<-decrypt> options. When used 359with B<-encrypt> or B<-decrypt> the supplied key is used to wrap or unwrap the 360content encryption key using an AES key in the B<KEKRecipientInfo> type. 361 362=item B<-secretkeyid id> 363 364the key identifier for the supplied symmetric key for B<KEKRecipientInfo> type. 365This option B<must> be present if the B<-secretkey> option is used with 366B<-encrypt>. With B<-decrypt> operations the B<id> is used to locate the 367relevant key if it is not supplied then an attempt is used to decrypt any 368B<KEKRecipientInfo> structures. 369 370=item B<-econtent_type type> 371 372set the encapsulated content type to B<type> if not supplied the B<Data> type 373is used. The B<type> argument can be any valid OID name in either text or 374numerical format. 375 376=item B<-inkey file> 377 378the private key to use when signing or decrypting. This must match the 379corresponding certificate. If this option is not specified then the 380private key must be included in the certificate file specified with 381the B<-recip> or B<-signer> file. When signing this option can be used 382multiple times to specify successive keys. 383 384=item B<-passin arg> 385 386the private key password source. For more information about the format of B<arg> 387see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)|openssl(1)>. 388 389=item B<-rand file(s)> 390 391a file or files containing random data used to seed the random number 392generator, or an EGD socket (see L<RAND_egd(3)|RAND_egd(3)>). 393Multiple files can be specified separated by a OS-dependent character. 394The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for 395all others. 396 397=item B<cert.pem...> 398 399one or more certificates of message recipients: used when encrypting 400a message. 401 402=item B<-to, -from, -subject> 403 404the relevant mail headers. These are included outside the signed 405portion of a message so they may be included manually. If signing 406then many S/MIME mail clients check the signers certificate's email 407address matches that specified in the From: address. 408 409=item B<-purpose, -ignore_critical, -issuer_checks, -crl_check, -crl_check_all, -policy_check, -extended_crl, -x509_strict, -policy -check_ss_sig> 410 411Set various certificate chain valiadition option. See the 412L<B<verify>|verify(1)> manual page for details. 413 414=back 415 416=head1 NOTES 417 418The MIME message must be sent without any blank lines between the 419headers and the output. Some mail programs will automatically add 420a blank line. Piping the mail directly to sendmail is one way to 421achieve the correct format. 422 423The supplied message to be signed or encrypted must include the 424necessary MIME headers or many S/MIME clients wont display it 425properly (if at all). You can use the B<-text> option to automatically 426add plain text headers. 427 428A "signed and encrypted" message is one where a signed message is 429then encrypted. This can be produced by encrypting an already signed 430message: see the examples section. 431 432This version of the program only allows one signer per message but it 433will verify multiple signers on received messages. Some S/MIME clients 434choke if a message contains multiple signers. It is possible to sign 435messages "in parallel" by signing an already signed message. 436 437The options B<-encrypt> and B<-decrypt> reflect common usage in S/MIME 438clients. Strictly speaking these process CMS enveloped data: CMS 439encrypted data is used for other purposes. 440 441The B<-resign> option uses an existing message digest when adding a new 442signer. This means that attributes must be present in at least one existing 443signer using the same message digest or this operation will fail. 444 445The B<-stream> and B<-indef> options enable experimental streaming I/O support. 446As a result the encoding is BER using indefinite length constructed encoding 447and no longer DER. Streaming is supported for the B<-encrypt> operation and the 448B<-sign> operation if the content is not detached. 449 450Streaming is always used for the B<-sign> operation with detached data but 451since the content is no longer part of the CMS structure the encoding 452remains DER. 453 454If the B<-decrypt> option is used without a recipient certificate then an 455attempt is made to locate the recipient by trying each potential recipient 456in turn using the supplied private key. To thwart the MMA attack 457(Bleichenbacher's attack on PKCS #1 v1.5 RSA padding) all recipients are 458tried whether they succeed or not and if no recipients match the message 459is "decrypted" using a random key which will typically output garbage. 460The B<-debug_decrypt> option can be used to disable the MMA attack protection 461and return an error if no recipient can be found: this option should be used 462with caution. For a fuller description see L<CMS_decrypt(3)|CMS_decrypt(3)>). 463 464=head1 EXIT CODES 465 466=over 4 467 468=item Z<>0 469 470the operation was completely successfully. 471 472=item Z<>1 473 474an error occurred parsing the command options. 475 476=item Z<>2 477 478one of the input files could not be read. 479 480=item Z<>3 481 482an error occurred creating the CMS file or when reading the MIME 483message. 484 485=item Z<>4 486 487an error occurred decrypting or verifying the message. 488 489=item Z<>5 490 491the message was verified correctly but an error occurred writing out 492the signers certificates. 493 494=back 495 496=head1 COMPATIBILITY WITH PKCS#7 format. 497 498The B<smime> utility can only process the older B<PKCS#7> format. The B<cms> 499utility supports Cryptographic Message Syntax format. Use of some features 500will result in messages which cannot be processed by applications which only 501support the older format. These are detailed below. 502 503The use of the B<-keyid> option with B<-sign> or B<-encrypt>. 504 505The B<-outform PEM> option uses different headers. 506 507The B<-compress> option. 508 509The B<-secretkey> option when used with B<-encrypt>. 510 511Additionally the B<-EncryptedData_create> and B<-data_create> type cannot 512be processed by the older B<smime> command. 513 514=head1 EXAMPLES 515 516Create a cleartext signed message: 517 518 openssl cms -sign -in message.txt -text -out mail.msg \ 519 -signer mycert.pem 520 521Create an opaque signed message 522 523 openssl cms -sign -in message.txt -text -out mail.msg -nodetach \ 524 -signer mycert.pem 525 526Create a signed message, include some additional certificates and 527read the private key from another file: 528 529 openssl cms -sign -in in.txt -text -out mail.msg \ 530 -signer mycert.pem -inkey mykey.pem -certfile mycerts.pem 531 532Create a signed message with two signers, use key identifier: 533 534 openssl cms -sign -in message.txt -text -out mail.msg \ 535 -signer mycert.pem -signer othercert.pem -keyid 536 537Send a signed message under Unix directly to sendmail, including headers: 538 539 openssl cms -sign -in in.txt -text -signer mycert.pem \ 540 -from steve@openssl.org -to someone@somewhere \ 541 -subject "Signed message" | sendmail someone@somewhere 542 543Verify a message and extract the signer's certificate if successful: 544 545 openssl cms -verify -in mail.msg -signer user.pem -out signedtext.txt 546 547Send encrypted mail using triple DES: 548 549 openssl cms -encrypt -in in.txt -from steve@openssl.org \ 550 -to someone@somewhere -subject "Encrypted message" \ 551 -des3 user.pem -out mail.msg 552 553Sign and encrypt mail: 554 555 openssl cms -sign -in ml.txt -signer my.pem -text \ 556 | openssl cms -encrypt -out mail.msg \ 557 -from steve@openssl.org -to someone@somewhere \ 558 -subject "Signed and Encrypted message" -des3 user.pem 559 560Note: the encryption command does not include the B<-text> option because the 561message being encrypted already has MIME headers. 562 563Decrypt mail: 564 565 openssl cms -decrypt -in mail.msg -recip mycert.pem -inkey key.pem 566 567The output from Netscape form signing is a PKCS#7 structure with the 568detached signature format. You can use this program to verify the 569signature by line wrapping the base64 encoded structure and surrounding 570it with: 571 572 -----BEGIN PKCS7----- 573 -----END PKCS7----- 574 575and using the command, 576 577 openssl cms -verify -inform PEM -in signature.pem -content content.txt 578 579alternatively you can base64 decode the signature and use 580 581 openssl cms -verify -inform DER -in signature.der -content content.txt 582 583Create an encrypted message using 128 bit Camellia: 584 585 openssl cms -encrypt -in plain.txt -camellia128 -out mail.msg cert.pem 586 587Add a signer to an existing message: 588 589 openssl cms -resign -in mail.msg -signer newsign.pem -out mail2.msg 590 591=head1 BUGS 592 593The MIME parser isn't very clever: it seems to handle most messages that I've 594thrown at it but it may choke on others. 595 596The code currently will only write out the signer's certificate to a file: if 597the signer has a separate encryption certificate this must be manually 598extracted. There should be some heuristic that determines the correct 599encryption certificate. 600 601Ideally a database should be maintained of a certificates for each email 602address. 603 604The code doesn't currently take note of the permitted symmetric encryption 605algorithms as supplied in the SMIMECapabilities signed attribute. this means the 606user has to manually include the correct encryption algorithm. It should store 607the list of permitted ciphers in a database and only use those. 608 609No revocation checking is done on the signer's certificate. 610 611=head1 HISTORY 612 613The use of multiple B<-signer> options and the B<-resign> command were first 614added in OpenSSL 1.0.0 615 616 617=cut 618