24 [B<-EncryptedData_encrypt>]
26 [B<-verify_receipt receipt>]
28 [B<-inform SMIME|PEM|DER>]
29 [B<-rctform SMIME|PEM|DER>]
31 [B<-outform SMIME|PEM|DER>]
32 [B<-stream -indef -noindef>]
34 [B<-content filename>]
42 [B<-attime timestamp>]
64 [B<-verify_depth num>]
65 [B<-verify_email email>]
66 [B<-verify_hostname hostname>]
68 [B<-verify_name name>]
86 [B<-receipt_request_all>]
87 [B<-receipt_request_first>]
88 [B<-receipt_request_from emailaddress>]
89 [B<-receipt_request_to emailaddress>]
90 [B<-receipt_request_print>]
93 [B<-econtent_type type>]
95 [B<-keyopt name:parameter>]
107 The B<cms> command handles S/MIME v3.1 mail. It can encrypt, decrypt, sign and
108 verify, compress and uncompress S/MIME messages.
112 There are fourteen operation options that set the type of operation to be
113 performed. The meaning of the other options varies according to the operation
120 Print out a usage message.
124 Encrypt mail for the given recipient certificates. Input file is the message
125 to be encrypted. The output file is the encrypted mail in MIME format. The
126 actual CMS type is <B>EnvelopedData<B>.
128 Note that no revocation check is done for the recipient cert, so if that
129 key has been compromised, others may be able to decrypt the text.
133 Decrypt mail using the supplied certificate and private key. Expects an
134 encrypted mail message in MIME format for the input file. The decrypted mail
135 is written to the output file.
137 =item B<-debug_decrypt>
139 This option sets the B<CMS_DEBUG_DECRYPT> flag. This option should be used
140 with caution: see the notes section below.
144 Sign mail using the supplied certificate and private key. Input file is
145 the message to be signed. The signed message in MIME format is written
150 Verify signed mail. Expects a signed mail message on input and outputs
151 the signed data. Both clear text and opaque signing is supported.
155 Takes an input message and writes out a PEM encoded CMS structure.
159 Resign a message: take an existing message and one or more new signers.
161 =item B<-data_create>
163 Create a CMS B<Data> type.
167 B<Data> type and output the content.
169 =item B<-digest_create>
171 Create a CMS B<DigestedData> type.
173 =item B<-digest_verify>
175 Verify a CMS B<DigestedData> type and output the content.
179 Create a CMS B<CompressedData> type. OpenSSL must be compiled with B<zlib>
180 support for this option to work, otherwise it will output an error.
184 Uncompress a CMS B<CompressedData> type and output the content. OpenSSL must be
185 compiled with B<zlib> support for this option to work, otherwise it will
188 =item B<-EncryptedData_encrypt>
190 Encrypt content using supplied symmetric key and algorithm using a CMS
191 B<EncryptedData> type and output the content.
193 =item B<-sign_receipt>
195 Generate and output a signed receipt for the supplied message. The input
196 message B<must> contain a signed receipt request. Functionality is otherwise
197 similar to the B<-sign> operation.
199 =item B<-verify_receipt receipt>
201 Verify a signed receipt in filename B<receipt>. The input message B<must>
202 contain the original receipt request. Functionality is otherwise similar
203 to the B<-verify> operation.
205 =item B<-in filename>
207 The input message to be encrypted or signed or the message to be decrypted
210 =item B<-inform SMIME|PEM|DER>
212 This specifies the input format for the CMS structure. The default
213 is B<SMIME> which reads an S/MIME format message. B<PEM> and B<DER>
214 format change this to expect PEM and DER format CMS structures
215 instead. This currently only affects the input format of the CMS
216 structure, if no CMS structure is being input (for example with
217 B<-encrypt> or B<-sign>) this option has no effect.
219 =item B<-rctform SMIME|PEM|DER>
221 Specify the format for a signed receipt for use with the B<-receipt_verify>
224 =item B<-out filename>
226 The message text that has been decrypted or verified or the output MIME
227 format message that has been signed or verified.
229 =item B<-outform SMIME|PEM|DER>
231 This specifies the output format for the CMS structure. The default
232 is B<SMIME> which writes an S/MIME format message. B<PEM> and B<DER>
233 format change this to write PEM and DER format CMS structures
234 instead. This currently only affects the output format of the CMS
235 structure, if no CMS structure is being output (for example with
236 B<-verify> or B<-decrypt>) this option has no effect.
238 =item B<-stream -indef -noindef>
240 The B<-stream> and B<-indef> options are equivalent and enable streaming I/O
241 for encoding operations. This permits single pass processing of data without
242 the need to hold the entire contents in memory, potentially supporting very
243 large files. Streaming is automatically set for S/MIME signing with detached
244 data if the output format is B<SMIME> it is currently off by default for all
249 Disable streaming I/O where it would produce and indefinite length constructed
250 encoding. This option currently has no effect. In future streaming will be
251 enabled by default on all relevant operations and this option will disable it.
253 =item B<-content filename>
255 This specifies a file containing the detached content, this is only
256 useful with the B<-verify> command. This is only usable if the CMS
257 structure is using the detached signature form where the content is
258 not included. This option will override any content if the input format
259 is S/MIME and it uses the multipart/signed MIME content type.
263 This option adds plain text (text/plain) MIME headers to the supplied
264 message if encrypting or signing. If decrypting or verifying it strips
265 off text headers: if the decrypted or verified message is not of MIME
266 type text/plain then an error occurs.
270 For the B<-cmsout> operation do not output the parsed CMS structure. This
271 is useful when combined with the B<-print> option or if the syntax of the CMS
272 structure is being checked.
276 For the B<-cmsout> operation print out all fields of the CMS structure. This
277 is mainly useful for testing purposes.
279 =item B<-CAfile file>
281 A file containing trusted CA certificates, only used with B<-verify>.
285 A directory containing trusted CA certificates, only used with
286 B<-verify>. This directory must be a standard certificate directory: that
287 is a hash of each subject name (using B<x509 -hash>) should be linked
292 Do not load the trusted CA certificates from the default file location
296 Do not load the trusted CA certificates from the default directory location
300 Digest algorithm to use when signing or resigning. If not present then the
301 default digest algorithm for the signing key will be used (usually SHA1).
305 The encryption algorithm to use. For example triple DES (168 bits) - B<-des3>
306 or 256 bit AES - B<-aes256>. Any standard algorithm name (as used by the
307 EVP_get_cipherbyname() function) can also be used preceded by a dash, for
308 example B<-aes-128-cbc>. See L<enc(1)> for a list of ciphers
309 supported by your version of OpenSSL.
311 If not specified triple DES is used. Only used with B<-encrypt> and
312 B<-EncryptedData_create> commands.
316 When verifying a message normally certificates (if any) included in
317 the message are searched for the signing certificate. With this option
318 only the certificates specified in the B<-certfile> option are used.
319 The supplied certificates can still be used as untrusted CAs however.
323 Do not verify the signers certificate of a signed message.
327 When signing a message the signer's certificate is normally included
328 with this option it is excluded. This will reduce the size of the
329 signed message but the verifier must have a copy of the signers certificate
330 available locally (passed using the B<-certfile> option for example).
334 Normally when a message is signed a set of attributes are included which
335 include the signing time and supported symmetric algorithms. With this
336 option they are not included.
340 Exclude the list of supported algorithms from signed attributes, other options
341 such as signing time and content type are still included.
345 Normally the input message is converted to "canonical" format which is
346 effectively using CR and LF as end of line: as required by the S/MIME
347 specification. When this option is present no translation occurs. This
348 is useful when handling binary data which may not be in MIME format.
352 Normally the output file uses a single B<LF> as end of line. When this
353 option is present B<CRLF> is used instead.
357 When signing use ASCII CRLF format canonicalisation. This strips trailing
358 whitespace from all lines, deletes trailing blank lines at EOF and sets
359 the encapsulated content type. This option is normally used with detached
360 content and an output signature format of DER. This option is not normally
361 needed when verifying as it is enabled automatically if the encapsulated
362 content format is detected.
366 When signing a message use opaque signing: this form is more resistant
367 to translation by mail relays but it cannot be read by mail agents that
368 do not support S/MIME. Without this option cleartext signing with
369 the MIME type multipart/signed is used.
371 =item B<-certfile file>
373 Allows additional certificates to be specified. When signing these will
374 be included with the message. When verifying these will be searched for
375 the signers certificates. The certificates should be in PEM format.
377 =item B<-certsout file>
379 Any certificates contained in the message are written to B<file>.
381 =item B<-signer file>
383 A signing certificate when signing or resigning a message, this option can be
384 used multiple times if more than one signer is required. If a message is being
385 verified then the signers certificates will be written to this file if the
386 verification was successful.
390 When decrypting a message this specifies the recipients certificate. The
391 certificate must match one of the recipients of the message or an error
394 When encrypting a message this option may be used multiple times to specify
395 each recipient. This form B<must> be used if customised parameters are
396 required (for example to specify RSA-OAEP).
398 Only certificates carrying RSA, Diffie-Hellman or EC keys are supported by this
403 Use subject key identifier to identify certificates instead of issuer name and
404 serial number. The supplied certificate B<must> include a subject key
405 identifier extension. Supported by B<-sign> and B<-encrypt> options.
407 =item B<-receipt_request_all>, B<-receipt_request_first>
409 For B<-sign> option include a signed receipt request. Indicate requests should
410 be provided by all recipient or first tier recipients (those mailed directly
411 and not from a mailing list). Ignored it B<-receipt_request_from> is included.
413 =item B<-receipt_request_from emailaddress>
415 For B<-sign> option include a signed receipt request. Add an explicit email
416 address where receipts should be supplied.
418 =item B<-receipt_request_to emailaddress>
420 Add an explicit email address where signed receipts should be sent to. This
421 option B<must> but supplied if a signed receipt it requested.
423 =item B<-receipt_request_print>
425 For the B<-verify> operation print out the contents of any signed receipt
428 =item B<-secretkey key>
430 Specify symmetric key to use. The key must be supplied in hex format and be
431 consistent with the algorithm used. Supported by the B<-EncryptedData_encrypt>
432 B<-EncryptedData_decrypt>, B<-encrypt> and B<-decrypt> options. When used
433 with B<-encrypt> or B<-decrypt> the supplied key is used to wrap or unwrap the
434 content encryption key using an AES key in the B<KEKRecipientInfo> type.
436 =item B<-secretkeyid id>
438 The key identifier for the supplied symmetric key for B<KEKRecipientInfo> type.
439 This option B<must> be present if the B<-secretkey> option is used with
440 B<-encrypt>. With B<-decrypt> operations the B<id> is used to locate the
441 relevant key if it is not supplied then an attempt is used to decrypt any
442 B<KEKRecipientInfo> structures.
444 =item B<-econtent_type type>
446 Set the encapsulated content type to B<type> if not supplied the B<Data> type
447 is used. The B<type> argument can be any valid OID name in either text or
452 The private key to use when signing or decrypting. This must match the
453 corresponding certificate. If this option is not specified then the
454 private key must be included in the certificate file specified with
455 the B<-recip> or B<-signer> file. When signing this option can be used
456 multiple times to specify successive keys.
458 =item B<-keyopt name:opt>
460 For signing and encryption this option can be used multiple times to
461 set customised parameters for the preceding key or certificate. It can
462 currently be used to set RSA-PSS for signing, RSA-OAEP for encryption
463 or to modify default parameters for ECDH.
467 The private key password source. For more information about the format of B<arg>
468 see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)>.
470 =item B<-rand file...>
472 A file or files containing random data used to seed the random number
474 Multiple files can be specified separated by an OS-dependent character.
475 The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for
478 =item [B<-writerand file>]
480 Writes random data to the specified I<file> upon exit.
481 This can be used with a subsequent B<-rand> flag.
485 One or more certificates of message recipients: used when encrypting
488 =item B<-to, -from, -subject>
490 The relevant mail headers. These are included outside the signed
491 portion of a message so they may be included manually. If signing
492 then many S/MIME mail clients check the signers certificate's email
493 address matches that specified in the From: address.
495 =item B<-attime>, B<-check_ss_sig>, B<-crl_check>, B<-crl_check_all>,
496 B<-explicit_policy>, B<-extended_crl>, B<-ignore_critical>, B<-inhibit_any>,
497 B<-inhibit_map>, B<-no_alt_chains>, B<-no_check_time>, B<-partial_chain>, B<-policy>,
498 B<-policy_check>, B<-policy_print>, B<-purpose>, B<-suiteB_128>,
499 B<-suiteB_128_only>, B<-suiteB_192>, B<-trusted_first>, B<-use_deltas>,
500 B<-auth_level>, B<-verify_depth>, B<-verify_email>, B<-verify_hostname>,
501 B<-verify_ip>, B<-verify_name>, B<-x509_strict>
503 Set various certificate chain validation options. See the
504 L<verify(1)> manual page for details.
510 The MIME message must be sent without any blank lines between the
511 headers and the output. Some mail programs will automatically add
512 a blank line. Piping the mail directly to sendmail is one way to
513 achieve the correct format.
515 The supplied message to be signed or encrypted must include the
516 necessary MIME headers or many S/MIME clients won't display it
517 properly (if at all). You can use the B<-text> option to automatically
518 add plain text headers.
520 A "signed and encrypted" message is one where a signed message is
521 then encrypted. This can be produced by encrypting an already signed
522 message: see the examples section.
524 This version of the program only allows one signer per message but it
525 will verify multiple signers on received messages. Some S/MIME clients
526 choke if a message contains multiple signers. It is possible to sign
527 messages "in parallel" by signing an already signed message.
529 The options B<-encrypt> and B<-decrypt> reflect common usage in S/MIME
530 clients. Strictly speaking these process CMS enveloped data: CMS
531 encrypted data is used for other purposes.
533 The B<-resign> option uses an existing message digest when adding a new
534 signer. This means that attributes must be present in at least one existing
535 signer using the same message digest or this operation will fail.
537 The B<-stream> and B<-indef> options enable streaming I/O support.
538 As a result the encoding is BER using indefinite length constructed encoding
539 and no longer DER. Streaming is supported for the B<-encrypt> operation and the
540 B<-sign> operation if the content is not detached.
542 Streaming is always used for the B<-sign> operation with detached data but
543 since the content is no longer part of the CMS structure the encoding
546 If the B<-decrypt> option is used without a recipient certificate then an
547 attempt is made to locate the recipient by trying each potential recipient
548 in turn using the supplied private key. To thwart the MMA attack
549 (Bleichenbacher's attack on PKCS #1 v1.5 RSA padding) all recipients are
550 tried whether they succeed or not and if no recipients match the message
551 is "decrypted" using a random key which will typically output garbage.
552 The B<-debug_decrypt> option can be used to disable the MMA attack protection
553 and return an error if no recipient can be found: this option should be used
554 with caution. For a fuller description see L<CMS_decrypt(3)>).
562 The operation was completely successfully.
566 An error occurred parsing the command options.
570 One of the input files could not be read.
574 An error occurred creating the CMS file or when reading the MIME
579 An error occurred decrypting or verifying the message.
583 The message was verified correctly but an error occurred writing out
584 the signers certificates.
588 =head1 COMPATIBILITY WITH PKCS#7 format.
590 The B<smime> utility can only process the older B<PKCS#7> format. The B<cms>
591 utility supports Cryptographic Message Syntax format. Use of some features
592 will result in messages which cannot be processed by applications which only
593 support the older format. These are detailed below.
595 The use of the B<-keyid> option with B<-sign> or B<-encrypt>.
597 The B<-outform PEM> option uses different headers.
599 The B<-compress> option.
601 The B<-secretkey> option when used with B<-encrypt>.
603 The use of PSS with B<-sign>.
605 The use of OAEP or non-RSA keys with B<-encrypt>.
607 Additionally the B<-EncryptedData_create> and B<-data_create> type cannot
608 be processed by the older B<smime> command.
612 Create a cleartext signed message:
614 openssl cms -sign -in message.txt -text -out mail.msg \
617 Create an opaque signed message
619 openssl cms -sign -in message.txt -text -out mail.msg -nodetach \
622 Create a signed message, include some additional certificates and
623 read the private key from another file:
625 openssl cms -sign -in in.txt -text -out mail.msg \
626 -signer mycert.pem -inkey mykey.pem -certfile mycerts.pem
628 Create a signed message with two signers, use key identifier:
630 openssl cms -sign -in message.txt -text -out mail.msg \
631 -signer mycert.pem -signer othercert.pem -keyid
633 Send a signed message under Unix directly to sendmail, including headers:
635 openssl cms -sign -in in.txt -text -signer mycert.pem \
636 -from steve@openssl.org -to someone@somewhere \
637 -subject "Signed message" | sendmail someone@somewhere
639 Verify a message and extract the signer's certificate if successful:
641 openssl cms -verify -in mail.msg -signer user.pem -out signedtext.txt
643 Send encrypted mail using triple DES:
645 openssl cms -encrypt -in in.txt -from steve@openssl.org \
646 -to someone@somewhere -subject "Encrypted message" \
647 -des3 user.pem -out mail.msg
649 Sign and encrypt mail:
651 openssl cms -sign -in ml.txt -signer my.pem -text \
652 | openssl cms -encrypt -out mail.msg \
653 -from steve@openssl.org -to someone@somewhere \
654 -subject "Signed and Encrypted message" -des3 user.pem
656 Note: the encryption command does not include the B<-text> option because the
657 message being encrypted already has MIME headers.
661 openssl cms -decrypt -in mail.msg -recip mycert.pem -inkey key.pem
663 The output from Netscape form signing is a PKCS#7 structure with the
664 detached signature format. You can use this program to verify the
665 signature by line wrapping the base64 encoded structure and surrounding
668 -----BEGIN PKCS7-----
671 and using the command,
673 openssl cms -verify -inform PEM -in signature.pem -content content.txt
675 alternatively you can base64 decode the signature and use
677 openssl cms -verify -inform DER -in signature.der -content content.txt
679 Create an encrypted message using 128 bit Camellia:
681 openssl cms -encrypt -in plain.txt -camellia128 -out mail.msg cert.pem
683 Add a signer to an existing message:
685 openssl cms -resign -in mail.msg -signer newsign.pem -out mail2.msg
687 Sign mail using RSA-PSS:
689 openssl cms -sign -in message.txt -text -out mail.msg \
690 -signer mycert.pem -keyopt rsa_padding_mode:pss
692 Create encrypted mail using RSA-OAEP:
694 openssl cms -encrypt -in plain.txt -out mail.msg \
695 -recip cert.pem -keyopt rsa_padding_mode:oaep
697 Use SHA256 KDF with an ECDH certificate:
699 openssl cms -encrypt -in plain.txt -out mail.msg \
700 -recip ecdhcert.pem -keyopt ecdh_kdf_md:sha256
704 The MIME parser isn't very clever: it seems to handle most messages that I've
705 thrown at it but it may choke on others.
707 The code currently will only write out the signer's certificate to a file: if
708 the signer has a separate encryption certificate this must be manually
709 extracted. There should be some heuristic that determines the correct
710 encryption certificate.
712 Ideally a database should be maintained of a certificates for each email
715 The code doesn't currently take note of the permitted symmetric encryption
716 algorithms as supplied in the SMIMECapabilities signed attribute. this means the
717 user has to manually include the correct encryption algorithm. It should store
718 the list of permitted ciphers in a database and only use those.
720 No revocation checking is done on the signer's certificate.
724 The use of multiple B<-signer> options and the B<-resign> command were first
725 added in OpenSSL 1.0.0.
727 The B<keyopt> option was added in OpenSSL 1.0.2.
729 Support for RSA-OAEP and RSA-PSS was added in OpenSSL 1.0.2.
731 The use of non-RSA keys with B<-encrypt> and B<-decrypt>
732 was added in OpenSSL 1.0.2.
734 The -no_alt_chains option was added in OpenSSL 1.0.2b.
738 Copyright 2008-2018 The OpenSSL Project Authors. All Rights Reserved.
740 Licensed under the OpenSSL license (the "License"). You may not use
741 this file except in compliance with the License. You can obtain a copy
742 in the file LICENSE in the source distribution or at
743 L<https://www.openssl.org/source/license.html>.