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>]
61 [B<-verify_depth num>]
62 [B<-verify_email email>]
63 [B<-verify_hostname hostname>]
65 [B<-verify_name name>]
70 [B<-no_signer_cert_verify>]
82 [B<-receipt_request_all -receipt_request_first>]
83 [B<-receipt_request_from emailaddress>]
84 [B<-receipt_request_to emailaddress>]
85 [B<-receipt_request_print>]
88 [B<-econtent_type type>]
90 [B<-keyopt name:parameter>]
101 The B<cms> command handles S/MIME v3.1 mail. It can encrypt, decrypt, sign and
102 verify, compress and uncompress S/MIME messages.
104 =head1 COMMAND OPTIONS
106 There are fourteen operation options that set the type of operation to be
107 performed. The meaning of the other options varies according to the operation
114 Print out a usage message.
118 encrypt mail for the given recipient certificates. Input file is the message
119 to be encrypted. The output file is the encrypted mail in MIME format. The
120 actual CMS type is <B>EnvelopedData<B>.
124 decrypt mail using the supplied certificate and private key. Expects an
125 encrypted mail message in MIME format for the input file. The decrypted mail
126 is written to the output file.
128 =item B<-debug_decrypt>
130 this option sets the B<CMS_DEBUG_DECRYPT> flag. This option should be used
131 with caution: see the notes section below.
135 sign mail using the supplied certificate and private key. Input file is
136 the message to be signed. The signed message in MIME format is written
141 verify signed mail. Expects a signed mail message on input and outputs
142 the signed data. Both clear text and opaque signing is supported.
146 takes an input message and writes out a PEM encoded CMS structure.
150 resign a message: take an existing message and one or more new signers.
152 =item B<-data_create>
154 Create a CMS B<Data> type.
158 B<Data> type and output the content.
160 =item B<-digest_create>
162 Create a CMS B<DigestedData> type.
164 =item B<-digest_verify>
166 Verify a CMS B<DigestedData> type and output the content.
170 Create a CMS B<CompressedData> type. OpenSSL must be compiled with B<zlib>
171 support for this option to work, otherwise it will output an error.
175 Uncompress a CMS B<CompressedData> type and output the content. OpenSSL must be
176 compiled with B<zlib> support for this option to work, otherwise it will
179 =item B<-EncryptedData_encrypt>
181 Encrypt content using supplied symmetric key and algorithm using a CMS
182 B<EncrytedData> type and output the content.
184 =item B<-sign_receipt>
186 Generate and output a signed receipt for the supplied message. The input
187 message B<must> contain a signed receipt request. Functionality is otherwise
188 similar to the B<-sign> operation.
190 =item B<-verify_receipt receipt>
192 Verify a signed receipt in filename B<receipt>. The input message B<must>
193 contain the original receipt request. Functionality is otherwise similar
194 to the B<-verify> operation.
196 =item B<-in filename>
198 the input message to be encrypted or signed or the message to be decrypted
201 =item B<-inform SMIME|PEM|DER>
203 this specifies the input format for the CMS structure. The default
204 is B<SMIME> which reads an S/MIME format message. B<PEM> and B<DER>
205 format change this to expect PEM and DER format CMS structures
206 instead. This currently only affects the input format of the CMS
207 structure, if no CMS structure is being input (for example with
208 B<-encrypt> or B<-sign>) this option has no effect.
210 =item B<-rctform SMIME|PEM|DER>
212 specify the format for a signed receipt for use with the B<-receipt_verify>
215 =item B<-out filename>
217 the message text that has been decrypted or verified or the output MIME
218 format message that has been signed or verified.
220 =item B<-outform SMIME|PEM|DER>
222 this specifies the output format for the CMS structure. The default
223 is B<SMIME> which writes an S/MIME format message. B<PEM> and B<DER>
224 format change this to write PEM and DER format CMS structures
225 instead. This currently only affects the output format of the CMS
226 structure, if no CMS structure is being output (for example with
227 B<-verify> or B<-decrypt>) this option has no effect.
229 =item B<-stream -indef -noindef>
231 the B<-stream> and B<-indef> options are equivalent and enable streaming I/O
232 for encoding operations. This permits single pass processing of data without
233 the need to hold the entire contents in memory, potentially supporting very
234 large files. Streaming is automatically set for S/MIME signing with detached
235 data if the output format is B<SMIME> it is currently off by default for all
240 disable streaming I/O where it would produce and indefinite length constructed
241 encoding. This option currently has no effect. In future streaming will be
242 enabled by default on all relevant operations and this option will disable it.
244 =item B<-content filename>
246 This specifies a file containing the detached content, this is only
247 useful with the B<-verify> command. This is only usable if the CMS
248 structure is using the detached signature form where the content is
249 not included. This option will override any content if the input format
250 is S/MIME and it uses the multipart/signed MIME content type.
254 this option adds plain text (text/plain) MIME headers to the supplied
255 message if encrypting or signing. If decrypting or verifying it strips
256 off text headers: if the decrypted or verified message is not of MIME
257 type text/plain then an error occurs.
261 for the B<-cmsout> operation do not output the parsed CMS structure. This
262 is useful when combined with the B<-print> option or if the syntax of the CMS
263 structure is being checked.
267 for the B<-cmsout> operation print out all fields of the CMS structure. This
268 is mainly useful for testing purposes.
270 =item B<-CAfile file>
272 a file containing trusted CA certificates, only used with B<-verify>.
276 a directory containing trusted CA certificates, only used with
277 B<-verify>. This directory must be a standard certificate directory: that
278 is a hash of each subject name (using B<x509 -hash>) should be linked
283 Do not load the trusted CA certificates from the default file location
287 Do not load the trusted CA certificates from the default directory location
291 digest algorithm to use when signing or resigning. If not present then the
292 default digest algorithm for the signing key will be used (usually SHA1).
296 the encryption algorithm to use. For example triple DES (168 bits) - B<-des3>
297 or 256 bit AES - B<-aes256>. Any standard algorithm name (as used by the
298 EVP_get_cipherbyname() function) can also be used preceded by a dash, for
299 example B<-aes-128-cbc>. See L<B<enc>|enc(1)> for a list of ciphers
300 supported by your version of OpenSSL.
302 If not specified triple DES is used. Only used with B<-encrypt> and
303 B<-EncryptedData_create> commands.
307 when verifying a message normally certificates (if any) included in
308 the message are searched for the signing certificate. With this option
309 only the certificates specified in the B<-certfile> option are used.
310 The supplied certificates can still be used as untrusted CAs however.
312 =item B<-no_signer_cert_verify>
314 do not verify the signers certificate of a signed message.
318 when signing a message the signer's certificate is normally included
319 with this option it is excluded. This will reduce the size of the
320 signed message but the verifier must have a copy of the signers certificate
321 available locally (passed using the B<-certfile> option for example).
325 normally when a message is signed a set of attributes are included which
326 include the signing time and supported symmetric algorithms. With this
327 option they are not included.
331 exclude the list of supported algorithms from signed attributes, other options
332 such as signing time and content type are still included.
336 normally the input message is converted to "canonical" format which is
337 effectively using CR and LF as end of line: as required by the S/MIME
338 specification. When this option is present no translation occurs. This
339 is useful when handling binary data which may not be in MIME format.
343 when signing use ASCII CRLF format canonicalisation. This strips trailing
344 whitespace from all lines, deletes trailing blank lines at EOF and sets
345 the encapsulated content type. This option is normally used with detached
346 content and an output signature format of DER. This option is not normally
347 needed when verifying as it is enabled automatically if the encapsulated
348 content format is detected.
352 when signing a message use opaque signing: this form is more resistant
353 to translation by mail relays but it cannot be read by mail agents that
354 do not support S/MIME. Without this option cleartext signing with
355 the MIME type multipart/signed is used.
357 =item B<-certfile file>
359 allows additional certificates to be specified. When signing these will
360 be included with the message. When verifying these will be searched for
361 the signers certificates. The certificates should be in PEM format.
363 =item B<-certsout file>
365 any certificates contained in the message are written to B<file>.
367 =item B<-signer file>
369 a signing certificate when signing or resigning a message, this option can be
370 used multiple times if more than one signer is required. If a message is being
371 verified then the signers certificates will be written to this file if the
372 verification was successful.
376 when decrypting a message this specifies the recipients certificate. The
377 certificate must match one of the recipients of the message or an error
380 When encrypting a message this option may be used multiple times to specify
381 each recipient. This form B<must> be used if customised parameters are
382 required (for example to specify RSA-OAEP).
386 use subject key identifier to identify certificates instead of issuer name and
387 serial number. The supplied certificate B<must> include a subject key
388 identifier extension. Supported by B<-sign> and B<-encrypt> options.
390 =item B<-receipt_request_all -receipt_request_first>
392 for B<-sign> option include a signed receipt request. Indicate requests should
393 be provided by all recipient or first tier recipients (those mailed directly
394 and not from a mailing list). Ignored it B<-receipt_request_from> is included.
396 =item B<-receipt_request_from emailaddress>
398 for B<-sign> option include a signed receipt request. Add an explicit email
399 address where receipts should be supplied.
401 =item B<-receipt_request_to emailaddress>
403 Add an explicit email address where signed receipts should be sent to. This
404 option B<must> but supplied if a signed receipt it requested.
406 =item B<-receipt_request_print>
408 For the B<-verify> operation print out the contents of any signed receipt
411 =item B<-secretkey key>
413 specify symmetric key to use. The key must be supplied in hex format and be
414 consistent with the algorithm used. Supported by the B<-EncryptedData_encrypt>
415 B<-EncryptedData_decrypt>, B<-encrypt> and B<-decrypt> options. When used
416 with B<-encrypt> or B<-decrypt> the supplied key is used to wrap or unwrap the
417 content encryption key using an AES key in the B<KEKRecipientInfo> type.
419 =item B<-secretkeyid id>
421 the key identifier for the supplied symmetric key for B<KEKRecipientInfo> type.
422 This option B<must> be present if the B<-secretkey> option is used with
423 B<-encrypt>. With B<-decrypt> operations the B<id> is used to locate the
424 relevant key if it is not supplied then an attempt is used to decrypt any
425 B<KEKRecipientInfo> structures.
427 =item B<-econtent_type type>
429 set the encapsulated content type to B<type> if not supplied the B<Data> type
430 is used. The B<type> argument can be any valid OID name in either text or
435 the private key to use when signing or decrypting. This must match the
436 corresponding certificate. If this option is not specified then the
437 private key must be included in the certificate file specified with
438 the B<-recip> or B<-signer> file. When signing this option can be used
439 multiple times to specify successive keys.
441 =item B<-keyopt name:opt>
443 for signing and encryption this option can be used multiple times to
444 set customised parameters for the preceding key or certificate. It can
445 currently be used to set RSA-PSS for signing, RSA-OAEP for encryption
446 or to modify default parameters for ECDH.
450 the private key password source. For more information about the format of B<arg>
451 see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)>.
453 =item B<-rand file(s)>
455 a file or files containing random data used to seed the random number
456 generator, or an EGD socket (see L<RAND_egd(3)>).
457 Multiple files can be specified separated by a OS-dependent character.
458 The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for
463 one or more certificates of message recipients: used when encrypting
466 =item B<-to, -from, -subject>
468 the relevant mail headers. These are included outside the signed
469 portion of a message so they may be included manually. If signing
470 then many S/MIME mail clients check the signers certificate's email
471 address matches that specified in the From: address.
473 =item B<-attime>, B<-check_ss_sig>, B<-crl_check>, B<-crl_check_all>,
474 B<-explicit_policy>, B<-extended_crl>, B<-ignore_critical>, B<-inhibit_any>,
475 B<-inhibit_map>, B<-no_alt_chains>, B<-partial_chain>, B<-policy>,
476 B<-policy_check>, B<-policy_print>, B<-purpose>, B<-suiteB_128>,
477 B<-suiteB_128_only>, B<-suiteB_192>, B<-trusted_first>, B<-use_deltas>,
478 B<-verify_depth>, B<-verify_email>, B<-verify_hostname>, B<-verify_ip>,
479 B<-verify_name>, B<-x509_strict>
481 Set various certificate chain validation options. See the
482 L<verify(1)> manual page for details.
488 The MIME message must be sent without any blank lines between the
489 headers and the output. Some mail programs will automatically add
490 a blank line. Piping the mail directly to sendmail is one way to
491 achieve the correct format.
493 The supplied message to be signed or encrypted must include the
494 necessary MIME headers or many S/MIME clients wont display it
495 properly (if at all). You can use the B<-text> option to automatically
496 add plain text headers.
498 A "signed and encrypted" message is one where a signed message is
499 then encrypted. This can be produced by encrypting an already signed
500 message: see the examples section.
502 This version of the program only allows one signer per message but it
503 will verify multiple signers on received messages. Some S/MIME clients
504 choke if a message contains multiple signers. It is possible to sign
505 messages "in parallel" by signing an already signed message.
507 The options B<-encrypt> and B<-decrypt> reflect common usage in S/MIME
508 clients. Strictly speaking these process CMS enveloped data: CMS
509 encrypted data is used for other purposes.
511 The B<-resign> option uses an existing message digest when adding a new
512 signer. This means that attributes must be present in at least one existing
513 signer using the same message digest or this operation will fail.
515 The B<-stream> and B<-indef> options enable streaming I/O support.
516 As a result the encoding is BER using indefinite length constructed encoding
517 and no longer DER. Streaming is supported for the B<-encrypt> operation and the
518 B<-sign> operation if the content is not detached.
520 Streaming is always used for the B<-sign> operation with detached data but
521 since the content is no longer part of the CMS structure the encoding
524 If the B<-decrypt> option is used without a recipient certificate then an
525 attempt is made to locate the recipient by trying each potential recipient
526 in turn using the supplied private key. To thwart the MMA attack
527 (Bleichenbacher's attack on PKCS #1 v1.5 RSA padding) all recipients are
528 tried whether they succeed or not and if no recipients match the message
529 is "decrypted" using a random key which will typically output garbage.
530 The B<-debug_decrypt> option can be used to disable the MMA attack protection
531 and return an error if no recipient can be found: this option should be used
532 with caution. For a fuller description see L<CMS_decrypt(3)>).
540 the operation was completely successfully.
544 an error occurred parsing the command options.
548 one of the input files could not be read.
552 an error occurred creating the CMS file or when reading the MIME
557 an error occurred decrypting or verifying the message.
561 the message was verified correctly but an error occurred writing out
562 the signers certificates.
566 =head1 COMPATIBILITY WITH PKCS#7 format.
568 The B<smime> utility can only process the older B<PKCS#7> format. The B<cms>
569 utility supports Cryptographic Message Syntax format. Use of some features
570 will result in messages which cannot be processed by applications which only
571 support the older format. These are detailed below.
573 The use of the B<-keyid> option with B<-sign> or B<-encrypt>.
575 The B<-outform PEM> option uses different headers.
577 The B<-compress> option.
579 The B<-secretkey> option when used with B<-encrypt>.
581 The use of PSS with B<-sign>.
583 The use of OAEP or non-RSA keys with B<-encrypt>.
585 Additionally the B<-EncryptedData_create> and B<-data_create> type cannot
586 be processed by the older B<smime> command.
590 Create a cleartext signed message:
592 openssl cms -sign -in message.txt -text -out mail.msg \
595 Create an opaque signed message
597 openssl cms -sign -in message.txt -text -out mail.msg -nodetach \
600 Create a signed message, include some additional certificates and
601 read the private key from another file:
603 openssl cms -sign -in in.txt -text -out mail.msg \
604 -signer mycert.pem -inkey mykey.pem -certfile mycerts.pem
606 Create a signed message with two signers, use key identifier:
608 openssl cms -sign -in message.txt -text -out mail.msg \
609 -signer mycert.pem -signer othercert.pem -keyid
611 Send a signed message under Unix directly to sendmail, including headers:
613 openssl cms -sign -in in.txt -text -signer mycert.pem \
614 -from steve@openssl.org -to someone@somewhere \
615 -subject "Signed message" | sendmail someone@somewhere
617 Verify a message and extract the signer's certificate if successful:
619 openssl cms -verify -in mail.msg -signer user.pem -out signedtext.txt
621 Send encrypted mail using triple DES:
623 openssl cms -encrypt -in in.txt -from steve@openssl.org \
624 -to someone@somewhere -subject "Encrypted message" \
625 -des3 user.pem -out mail.msg
627 Sign and encrypt mail:
629 openssl cms -sign -in ml.txt -signer my.pem -text \
630 | openssl cms -encrypt -out mail.msg \
631 -from steve@openssl.org -to someone@somewhere \
632 -subject "Signed and Encrypted message" -des3 user.pem
634 Note: the encryption command does not include the B<-text> option because the
635 message being encrypted already has MIME headers.
639 openssl cms -decrypt -in mail.msg -recip mycert.pem -inkey key.pem
641 The output from Netscape form signing is a PKCS#7 structure with the
642 detached signature format. You can use this program to verify the
643 signature by line wrapping the base64 encoded structure and surrounding
646 -----BEGIN PKCS7-----
649 and using the command,
651 openssl cms -verify -inform PEM -in signature.pem -content content.txt
653 alternatively you can base64 decode the signature and use
655 openssl cms -verify -inform DER -in signature.der -content content.txt
657 Create an encrypted message using 128 bit Camellia:
659 openssl cms -encrypt -in plain.txt -camellia128 -out mail.msg cert.pem
661 Add a signer to an existing message:
663 openssl cms -resign -in mail.msg -signer newsign.pem -out mail2.msg
665 Sign mail using RSA-PSS:
667 openssl cms -sign -in message.txt -text -out mail.msg \
668 -signer mycert.pem -keyopt rsa_padding_mode:pss
670 Create encrypted mail using RSA-OAEP:
672 openssl cms -encrypt -in plain.txt -out mail.msg \
673 -recip cert.pem -keyopt rsa_padding_mode:oaep
675 Use SHA256 KDF with an ECDH certificate:
677 openssl cms -encrypt -in plain.txt -out mail.msg \
678 -recip ecdhcert.pem -keyopt ecdh_kdf_md:sha256
682 The MIME parser isn't very clever: it seems to handle most messages that I've
683 thrown at it but it may choke on others.
685 The code currently will only write out the signer's certificate to a file: if
686 the signer has a separate encryption certificate this must be manually
687 extracted. There should be some heuristic that determines the correct
688 encryption certificate.
690 Ideally a database should be maintained of a certificates for each email
693 The code doesn't currently take note of the permitted symmetric encryption
694 algorithms as supplied in the SMIMECapabilities signed attribute. this means the
695 user has to manually include the correct encryption algorithm. It should store
696 the list of permitted ciphers in a database and only use those.
698 No revocation checking is done on the signer's certificate.
702 The use of multiple B<-signer> options and the B<-resign> command were first
703 added in OpenSSL 1.0.0
705 The B<keyopt> option was first added in OpenSSL 1.1.0
707 The use of B<-recip> to specify the recipient when encrypting mail was first
708 added to OpenSSL 1.1.0
710 Support for RSA-OAEP and RSA-PSS was first added to OpenSSL 1.1.0.
712 The use of non-RSA keys with B<-encrypt> and B<-decrypt> was first added
715 The -no_alt_chains options was first added to OpenSSL 1.1.0.