23 [B<-EncryptedData_encrypt>]
25 [B<-verify_receipt receipt>]
27 [B<-inform SMIME|PEM|DER>]
28 [B<-rctform SMIME|PEM|DER>]
30 [B<-outform SMIME|PEM|DER>]
31 [B<-stream -indef -noindef>]
33 [B<-content filename>]
41 [B<-attime timestamp>]
62 [B<-verify_depth num>]
63 [B<-verify_email email>]
64 [B<-verify_hostname hostname>]
66 [B<-verify_name name>]
71 [B<-no_signer_cert_verify>]
83 [B<-receipt_request_all -receipt_request_first>]
84 [B<-receipt_request_from emailaddress>]
85 [B<-receipt_request_to emailaddress>]
86 [B<-receipt_request_print>]
89 [B<-econtent_type type>]
91 [B<-keyopt name:parameter>]
102 The B<cms> command handles S/MIME v3.1 mail. It can encrypt, decrypt, sign and
103 verify, compress and uncompress S/MIME messages.
105 =head1 COMMAND OPTIONS
107 There are fourteen operation options that set the type of operation to be
108 performed. The meaning of the other options varies according to the operation
115 Print out a usage message.
119 encrypt mail for the given recipient certificates. Input file is the message
120 to be encrypted. The output file is the encrypted mail in MIME format. The
121 actual CMS type is <B>EnvelopedData<B>.
125 decrypt mail using the supplied certificate and private key. Expects an
126 encrypted mail message in MIME format for the input file. The decrypted mail
127 is written to the output file.
129 =item B<-debug_decrypt>
131 this option sets the B<CMS_DEBUG_DECRYPT> flag. This option should be used
132 with caution: see the notes section below.
136 sign mail using the supplied certificate and private key. Input file is
137 the message to be signed. The signed message in MIME format is written
142 verify signed mail. Expects a signed mail message on input and outputs
143 the signed data. Both clear text and opaque signing is supported.
147 takes an input message and writes out a PEM encoded CMS structure.
151 resign a message: take an existing message and one or more new signers.
153 =item B<-data_create>
155 Create a CMS B<Data> type.
159 B<Data> type and output the content.
161 =item B<-digest_create>
163 Create a CMS B<DigestedData> type.
165 =item B<-digest_verify>
167 Verify a CMS B<DigestedData> type and output the content.
171 Create a CMS B<CompressedData> type. OpenSSL must be compiled with B<zlib>
172 support for this option to work, otherwise it will output an error.
176 Uncompress a CMS B<CompressedData> type and output the content. OpenSSL must be
177 compiled with B<zlib> support for this option to work, otherwise it will
180 =item B<-EncryptedData_encrypt>
182 Encrypt content using supplied symmetric key and algorithm using a CMS
183 B<EncrytedData> type and output the content.
185 =item B<-sign_receipt>
187 Generate and output a signed receipt for the supplied message. The input
188 message B<must> contain a signed receipt request. Functionality is otherwise
189 similar to the B<-sign> operation.
191 =item B<-verify_receipt receipt>
193 Verify a signed receipt in filename B<receipt>. The input message B<must>
194 contain the original receipt request. Functionality is otherwise similar
195 to the B<-verify> operation.
197 =item B<-in filename>
199 the input message to be encrypted or signed or the message to be decrypted
202 =item B<-inform SMIME|PEM|DER>
204 this specifies the input format for the CMS structure. The default
205 is B<SMIME> which reads an S/MIME format message. B<PEM> and B<DER>
206 format change this to expect PEM and DER format CMS structures
207 instead. This currently only affects the input format of the CMS
208 structure, if no CMS structure is being input (for example with
209 B<-encrypt> or B<-sign>) this option has no effect.
211 =item B<-rctform SMIME|PEM|DER>
213 specify the format for a signed receipt for use with the B<-receipt_verify>
216 =item B<-out filename>
218 the message text that has been decrypted or verified or the output MIME
219 format message that has been signed or verified.
221 =item B<-outform SMIME|PEM|DER>
223 this specifies the output format for the CMS structure. The default
224 is B<SMIME> which writes an S/MIME format message. B<PEM> and B<DER>
225 format change this to write PEM and DER format CMS structures
226 instead. This currently only affects the output format of the CMS
227 structure, if no CMS structure is being output (for example with
228 B<-verify> or B<-decrypt>) this option has no effect.
230 =item B<-stream -indef -noindef>
232 the B<-stream> and B<-indef> options are equivalent and enable streaming I/O
233 for encoding operations. This permits single pass processing of data without
234 the need to hold the entire contents in memory, potentially supporting very
235 large files. Streaming is automatically set for S/MIME signing with detached
236 data if the output format is B<SMIME> it is currently off by default for all
241 disable streaming I/O where it would produce and indefinite length constructed
242 encoding. This option currently has no effect. In future streaming will be
243 enabled by default on all relevant operations and this option will disable it.
245 =item B<-content filename>
247 This specifies a file containing the detached content, this is only
248 useful with the B<-verify> command. This is only usable if the CMS
249 structure is using the detached signature form where the content is
250 not included. This option will override any content if the input format
251 is S/MIME and it uses the multipart/signed MIME content type.
255 this option adds plain text (text/plain) MIME headers to the supplied
256 message if encrypting or signing. If decrypting or verifying it strips
257 off text headers: if the decrypted or verified message is not of MIME
258 type text/plain then an error occurs.
262 for the B<-cmsout> operation do not output the parsed CMS structure. This
263 is useful when combined with the B<-print> option or if the syntax of the CMS
264 structure is being checked.
268 for the B<-cmsout> operation print out all fields of the CMS structure. This
269 is mainly useful for testing purposes.
271 =item B<-CAfile file>
273 a file containing trusted CA certificates, only used with B<-verify>.
277 a directory containing trusted CA certificates, only used with
278 B<-verify>. This directory must be a standard certificate directory: that
279 is a hash of each subject name (using B<x509 -hash>) should be linked
284 Do not load the trusted CA certificates from the default file location
288 Do not load the trusted CA certificates from the default directory location
292 digest algorithm to use when signing or resigning. If not present then the
293 default digest algorithm for the signing key will be used (usually SHA1).
297 the encryption algorithm to use. For example triple DES (168 bits) - B<-des3>
298 or 256 bit AES - B<-aes256>. Any standard algorithm name (as used by the
299 EVP_get_cipherbyname() function) can also be used preceded by a dash, for
300 example B<-aes-128-cbc>. See L<B<enc>|enc(1)> for a list of ciphers
301 supported by your version of OpenSSL.
303 If not specified triple DES is used. Only used with B<-encrypt> and
304 B<-EncryptedData_create> commands.
308 when verifying a message normally certificates (if any) included in
309 the message are searched for the signing certificate. With this option
310 only the certificates specified in the B<-certfile> option are used.
311 The supplied certificates can still be used as untrusted CAs however.
313 =item B<-no_signer_cert_verify>
315 do not verify the signers certificate of a signed message.
319 when signing a message the signer's certificate is normally included
320 with this option it is excluded. This will reduce the size of the
321 signed message but the verifier must have a copy of the signers certificate
322 available locally (passed using the B<-certfile> option for example).
326 normally when a message is signed a set of attributes are included which
327 include the signing time and supported symmetric algorithms. With this
328 option they are not included.
332 exclude the list of supported algorithms from signed attributes, other options
333 such as signing time and content type are still included.
337 normally the input message is converted to "canonical" format which is
338 effectively using CR and LF as end of line: as required by the S/MIME
339 specification. When this option is present no translation occurs. This
340 is useful when handling binary data which may not be in MIME format.
344 when signing use ASCII CRLF format canonicalisation. This strips trailing
345 whitespace from all lines, deletes trailing blank lines at EOF and sets
346 the encapsulated content type. This option is normally used with detached
347 content and an output signature format of DER. This option is not normally
348 needed when verifying as it is enabled automatically if the encapsulated
349 content format is detected.
353 when signing a message use opaque signing: this form is more resistant
354 to translation by mail relays but it cannot be read by mail agents that
355 do not support S/MIME. Without this option cleartext signing with
356 the MIME type multipart/signed is used.
358 =item B<-certfile file>
360 allows additional certificates to be specified. When signing these will
361 be included with the message. When verifying these will be searched for
362 the signers certificates. The certificates should be in PEM format.
364 =item B<-certsout file>
366 any certificates contained in the message are written to B<file>.
368 =item B<-signer file>
370 a signing certificate when signing or resigning a message, this option can be
371 used multiple times if more than one signer is required. If a message is being
372 verified then the signers certificates will be written to this file if the
373 verification was successful.
377 when decrypting a message this specifies the recipients certificate. The
378 certificate must match one of the recipients of the message or an error
381 When encrypting a message this option may be used multiple times to specify
382 each recipient. This form B<must> be used if customised parameters are
383 required (for example to specify RSA-OAEP).
387 use subject key identifier to identify certificates instead of issuer name and
388 serial number. The supplied certificate B<must> include a subject key
389 identifier extension. Supported by B<-sign> and B<-encrypt> options.
391 =item B<-receipt_request_all -receipt_request_first>
393 for B<-sign> option include a signed receipt request. Indicate requests should
394 be provided by all recipient or first tier recipients (those mailed directly
395 and not from a mailing list). Ignored it B<-receipt_request_from> is included.
397 =item B<-receipt_request_from emailaddress>
399 for B<-sign> option include a signed receipt request. Add an explicit email
400 address where receipts should be supplied.
402 =item B<-receipt_request_to emailaddress>
404 Add an explicit email address where signed receipts should be sent to. This
405 option B<must> but supplied if a signed receipt it requested.
407 =item B<-receipt_request_print>
409 For the B<-verify> operation print out the contents of any signed receipt
412 =item B<-secretkey key>
414 specify symmetric key to use. The key must be supplied in hex format and be
415 consistent with the algorithm used. Supported by the B<-EncryptedData_encrypt>
416 B<-EncryptedData_decrypt>, B<-encrypt> and B<-decrypt> options. When used
417 with B<-encrypt> or B<-decrypt> the supplied key is used to wrap or unwrap the
418 content encryption key using an AES key in the B<KEKRecipientInfo> type.
420 =item B<-secretkeyid id>
422 the key identifier for the supplied symmetric key for B<KEKRecipientInfo> type.
423 This option B<must> be present if the B<-secretkey> option is used with
424 B<-encrypt>. With B<-decrypt> operations the B<id> is used to locate the
425 relevant key if it is not supplied then an attempt is used to decrypt any
426 B<KEKRecipientInfo> structures.
428 =item B<-econtent_type type>
430 set the encapsulated content type to B<type> if not supplied the B<Data> type
431 is used. The B<type> argument can be any valid OID name in either text or
436 the private key to use when signing or decrypting. This must match the
437 corresponding certificate. If this option is not specified then the
438 private key must be included in the certificate file specified with
439 the B<-recip> or B<-signer> file. When signing this option can be used
440 multiple times to specify successive keys.
442 =item B<-keyopt name:opt>
444 for signing and encryption this option can be used multiple times to
445 set customised parameters for the preceding key or certificate. It can
446 currently be used to set RSA-PSS for signing, RSA-OAEP for encryption
447 or to modify default parameters for ECDH.
451 the private key password source. For more information about the format of B<arg>
452 see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)>.
454 =item B<-rand file(s)>
456 a file or files containing random data used to seed the random number
457 generator, or an EGD socket (see L<RAND_egd(3)>).
458 Multiple files can be specified separated by an OS-dependent character.
459 The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for
464 one or more certificates of message recipients: used when encrypting
467 =item B<-to, -from, -subject>
469 the relevant mail headers. These are included outside the signed
470 portion of a message so they may be included manually. If signing
471 then many S/MIME mail clients check the signers certificate's email
472 address matches that specified in the From: address.
474 =item B<-attime>, B<-check_ss_sig>, B<-crl_check>, B<-crl_check_all>,
475 B<-explicit_policy>, B<-extended_crl>, B<-ignore_critical>, B<-inhibit_any>,
476 B<-inhibit_map>, B<-no_alt_chains>, B<-partial_chain>, B<-policy>,
477 B<-policy_check>, B<-policy_print>, B<-purpose>, B<-suiteB_128>,
478 B<-suiteB_128_only>, B<-suiteB_192>, B<-trusted_first>, B<-use_deltas>,
479 B<-auth_level>, B<-verify_depth>, B<-verify_email>, B<-verify_hostname>,
480 B<-verify_ip>, B<-verify_name>, B<-x509_strict>
482 Set various certificate chain validation options. See the
483 L<verify(1)> manual page for details.
489 The MIME message must be sent without any blank lines between the
490 headers and the output. Some mail programs will automatically add
491 a blank line. Piping the mail directly to sendmail is one way to
492 achieve the correct format.
494 The supplied message to be signed or encrypted must include the
495 necessary MIME headers or many S/MIME clients wont display it
496 properly (if at all). You can use the B<-text> option to automatically
497 add plain text headers.
499 A "signed and encrypted" message is one where a signed message is
500 then encrypted. This can be produced by encrypting an already signed
501 message: see the examples section.
503 This version of the program only allows one signer per message but it
504 will verify multiple signers on received messages. Some S/MIME clients
505 choke if a message contains multiple signers. It is possible to sign
506 messages "in parallel" by signing an already signed message.
508 The options B<-encrypt> and B<-decrypt> reflect common usage in S/MIME
509 clients. Strictly speaking these process CMS enveloped data: CMS
510 encrypted data is used for other purposes.
512 The B<-resign> option uses an existing message digest when adding a new
513 signer. This means that attributes must be present in at least one existing
514 signer using the same message digest or this operation will fail.
516 The B<-stream> and B<-indef> options enable streaming I/O support.
517 As a result the encoding is BER using indefinite length constructed encoding
518 and no longer DER. Streaming is supported for the B<-encrypt> operation and the
519 B<-sign> operation if the content is not detached.
521 Streaming is always used for the B<-sign> operation with detached data but
522 since the content is no longer part of the CMS structure the encoding
525 If the B<-decrypt> option is used without a recipient certificate then an
526 attempt is made to locate the recipient by trying each potential recipient
527 in turn using the supplied private key. To thwart the MMA attack
528 (Bleichenbacher's attack on PKCS #1 v1.5 RSA padding) all recipients are
529 tried whether they succeed or not and if no recipients match the message
530 is "decrypted" using a random key which will typically output garbage.
531 The B<-debug_decrypt> option can be used to disable the MMA attack protection
532 and return an error if no recipient can be found: this option should be used
533 with caution. For a fuller description see L<CMS_decrypt(3)>).
541 the operation was completely successfully.
545 an error occurred parsing the command options.
549 one of the input files could not be read.
553 an error occurred creating the CMS file or when reading the MIME
558 an error occurred decrypting or verifying the message.
562 the message was verified correctly but an error occurred writing out
563 the signers certificates.
567 =head1 COMPATIBILITY WITH PKCS#7 format.
569 The B<smime> utility can only process the older B<PKCS#7> format. The B<cms>
570 utility supports Cryptographic Message Syntax format. Use of some features
571 will result in messages which cannot be processed by applications which only
572 support the older format. These are detailed below.
574 The use of the B<-keyid> option with B<-sign> or B<-encrypt>.
576 The B<-outform PEM> option uses different headers.
578 The B<-compress> option.
580 The B<-secretkey> option when used with B<-encrypt>.
582 The use of PSS with B<-sign>.
584 The use of OAEP or non-RSA keys with B<-encrypt>.
586 Additionally the B<-EncryptedData_create> and B<-data_create> type cannot
587 be processed by the older B<smime> command.
591 Create a cleartext signed message:
593 openssl cms -sign -in message.txt -text -out mail.msg \
596 Create an opaque signed message
598 openssl cms -sign -in message.txt -text -out mail.msg -nodetach \
601 Create a signed message, include some additional certificates and
602 read the private key from another file:
604 openssl cms -sign -in in.txt -text -out mail.msg \
605 -signer mycert.pem -inkey mykey.pem -certfile mycerts.pem
607 Create a signed message with two signers, use key identifier:
609 openssl cms -sign -in message.txt -text -out mail.msg \
610 -signer mycert.pem -signer othercert.pem -keyid
612 Send a signed message under Unix directly to sendmail, including headers:
614 openssl cms -sign -in in.txt -text -signer mycert.pem \
615 -from steve@openssl.org -to someone@somewhere \
616 -subject "Signed message" | sendmail someone@somewhere
618 Verify a message and extract the signer's certificate if successful:
620 openssl cms -verify -in mail.msg -signer user.pem -out signedtext.txt
622 Send encrypted mail using triple DES:
624 openssl cms -encrypt -in in.txt -from steve@openssl.org \
625 -to someone@somewhere -subject "Encrypted message" \
626 -des3 user.pem -out mail.msg
628 Sign and encrypt mail:
630 openssl cms -sign -in ml.txt -signer my.pem -text \
631 | openssl cms -encrypt -out mail.msg \
632 -from steve@openssl.org -to someone@somewhere \
633 -subject "Signed and Encrypted message" -des3 user.pem
635 Note: the encryption command does not include the B<-text> option because the
636 message being encrypted already has MIME headers.
640 openssl cms -decrypt -in mail.msg -recip mycert.pem -inkey key.pem
642 The output from Netscape form signing is a PKCS#7 structure with the
643 detached signature format. You can use this program to verify the
644 signature by line wrapping the base64 encoded structure and surrounding
647 -----BEGIN PKCS7-----
650 and using the command,
652 openssl cms -verify -inform PEM -in signature.pem -content content.txt
654 alternatively you can base64 decode the signature and use
656 openssl cms -verify -inform DER -in signature.der -content content.txt
658 Create an encrypted message using 128 bit Camellia:
660 openssl cms -encrypt -in plain.txt -camellia128 -out mail.msg cert.pem
662 Add a signer to an existing message:
664 openssl cms -resign -in mail.msg -signer newsign.pem -out mail2.msg
666 Sign mail using RSA-PSS:
668 openssl cms -sign -in message.txt -text -out mail.msg \
669 -signer mycert.pem -keyopt rsa_padding_mode:pss
671 Create encrypted mail using RSA-OAEP:
673 openssl cms -encrypt -in plain.txt -out mail.msg \
674 -recip cert.pem -keyopt rsa_padding_mode:oaep
676 Use SHA256 KDF with an ECDH certificate:
678 openssl cms -encrypt -in plain.txt -out mail.msg \
679 -recip ecdhcert.pem -keyopt ecdh_kdf_md:sha256
683 The MIME parser isn't very clever: it seems to handle most messages that I've
684 thrown at it but it may choke on others.
686 The code currently will only write out the signer's certificate to a file: if
687 the signer has a separate encryption certificate this must be manually
688 extracted. There should be some heuristic that determines the correct
689 encryption certificate.
691 Ideally a database should be maintained of a certificates for each email
694 The code doesn't currently take note of the permitted symmetric encryption
695 algorithms as supplied in the SMIMECapabilities signed attribute. this means the
696 user has to manually include the correct encryption algorithm. It should store
697 the list of permitted ciphers in a database and only use those.
699 No revocation checking is done on the signer's certificate.
703 The use of multiple B<-signer> options and the B<-resign> command were first
704 added in OpenSSL 1.0.0
706 The B<keyopt> option was first added in OpenSSL 1.1.0
708 The use of B<-recip> to specify the recipient when encrypting mail was first
709 added to OpenSSL 1.1.0
711 Support for RSA-OAEP and RSA-PSS was first added to OpenSSL 1.1.0.
713 The use of non-RSA keys with B<-encrypt> and B<-decrypt> was first added
716 The -no_alt_chains options was first added to OpenSSL 1.1.0.