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>]
63 [B<-verify_depth num>]
64 [B<-verify_email email>]
65 [B<-verify_hostname hostname>]
67 [B<-verify_name name>]
72 [B<-no_signer_cert_verify>]
84 [B<-receipt_request_all -receipt_request_first>]
85 [B<-receipt_request_from emailaddress>]
86 [B<-receipt_request_to emailaddress>]
87 [B<-receipt_request_print>]
90 [B<-econtent_type type>]
92 [B<-keyopt name:parameter>]
103 The B<cms> command handles S/MIME v3.1 mail. It can encrypt, decrypt, sign and
104 verify, compress and uncompress S/MIME messages.
106 =head1 COMMAND OPTIONS
108 There are fourteen operation options that set the type of operation to be
109 performed. The meaning of the other options varies according to the operation
116 Print out a usage message.
120 encrypt mail for the given recipient certificates. Input file is the message
121 to be encrypted. The output file is the encrypted mail in MIME format. The
122 actual CMS type is <B>EnvelopedData<B>.
126 decrypt mail using the supplied certificate and private key. Expects an
127 encrypted mail message in MIME format for the input file. The decrypted mail
128 is written to the output file.
130 =item B<-debug_decrypt>
132 this option sets the B<CMS_DEBUG_DECRYPT> flag. This option should be used
133 with caution: see the notes section below.
137 sign mail using the supplied certificate and private key. Input file is
138 the message to be signed. The signed message in MIME format is written
143 verify signed mail. Expects a signed mail message on input and outputs
144 the signed data. Both clear text and opaque signing is supported.
148 takes an input message and writes out a PEM encoded CMS structure.
152 resign a message: take an existing message and one or more new signers.
154 =item B<-data_create>
156 Create a CMS B<Data> type.
160 B<Data> type and output the content.
162 =item B<-digest_create>
164 Create a CMS B<DigestedData> type.
166 =item B<-digest_verify>
168 Verify a CMS B<DigestedData> type and output the content.
172 Create a CMS B<CompressedData> type. OpenSSL must be compiled with B<zlib>
173 support for this option to work, otherwise it will output an error.
177 Uncompress a CMS B<CompressedData> type and output the content. OpenSSL must be
178 compiled with B<zlib> support for this option to work, otherwise it will
181 =item B<-EncryptedData_encrypt>
183 Encrypt content using supplied symmetric key and algorithm using a CMS
184 B<EncrytedData> type and output the content.
186 =item B<-sign_receipt>
188 Generate and output a signed receipt for the supplied message. The input
189 message B<must> contain a signed receipt request. Functionality is otherwise
190 similar to the B<-sign> operation.
192 =item B<-verify_receipt receipt>
194 Verify a signed receipt in filename B<receipt>. The input message B<must>
195 contain the original receipt request. Functionality is otherwise similar
196 to the B<-verify> operation.
198 =item B<-in filename>
200 the input message to be encrypted or signed or the message to be decrypted
203 =item B<-inform SMIME|PEM|DER>
205 this specifies the input format for the CMS structure. The default
206 is B<SMIME> which reads an S/MIME format message. B<PEM> and B<DER>
207 format change this to expect PEM and DER format CMS structures
208 instead. This currently only affects the input format of the CMS
209 structure, if no CMS structure is being input (for example with
210 B<-encrypt> or B<-sign>) this option has no effect.
212 =item B<-rctform SMIME|PEM|DER>
214 specify the format for a signed receipt for use with the B<-receipt_verify>
217 =item B<-out filename>
219 the message text that has been decrypted or verified or the output MIME
220 format message that has been signed or verified.
222 =item B<-outform SMIME|PEM|DER>
224 this specifies the output format for the CMS structure. The default
225 is B<SMIME> which writes an S/MIME format message. B<PEM> and B<DER>
226 format change this to write PEM and DER format CMS structures
227 instead. This currently only affects the output format of the CMS
228 structure, if no CMS structure is being output (for example with
229 B<-verify> or B<-decrypt>) this option has no effect.
231 =item B<-stream -indef -noindef>
233 the B<-stream> and B<-indef> options are equivalent and enable streaming I/O
234 for encoding operations. This permits single pass processing of data without
235 the need to hold the entire contents in memory, potentially supporting very
236 large files. Streaming is automatically set for S/MIME signing with detached
237 data if the output format is B<SMIME> it is currently off by default for all
242 disable streaming I/O where it would produce and indefinite length constructed
243 encoding. This option currently has no effect. In future streaming will be
244 enabled by default on all relevant operations and this option will disable it.
246 =item B<-content filename>
248 This specifies a file containing the detached content, this is only
249 useful with the B<-verify> command. This is only usable if the CMS
250 structure is using the detached signature form where the content is
251 not included. This option will override any content if the input format
252 is S/MIME and it uses the multipart/signed MIME content type.
256 this option adds plain text (text/plain) MIME headers to the supplied
257 message if encrypting or signing. If decrypting or verifying it strips
258 off text headers: if the decrypted or verified message is not of MIME
259 type text/plain then an error occurs.
263 for the B<-cmsout> operation do not output the parsed CMS structure. This
264 is useful when combined with the B<-print> option or if the syntax of the CMS
265 structure is being checked.
269 for the B<-cmsout> operation print out all fields of the CMS structure. This
270 is mainly useful for testing purposes.
272 =item B<-CAfile file>
274 a file containing trusted CA certificates, only used with B<-verify>.
278 a directory containing trusted CA certificates, only used with
279 B<-verify>. This directory must be a standard certificate directory: that
280 is a hash of each subject name (using B<x509 -hash>) should be linked
285 Do not load the trusted CA certificates from the default file location
289 Do not load the trusted CA certificates from the default directory location
293 digest algorithm to use when signing or resigning. If not present then the
294 default digest algorithm for the signing key will be used (usually SHA1).
298 the encryption algorithm to use. For example triple DES (168 bits) - B<-des3>
299 or 256 bit AES - B<-aes256>. Any standard algorithm name (as used by the
300 EVP_get_cipherbyname() function) can also be used preceded by a dash, for
301 example B<-aes-128-cbc>. See L<B<enc>|enc(1)> for a list of ciphers
302 supported by your version of OpenSSL.
304 If not specified triple DES is used. Only used with B<-encrypt> and
305 B<-EncryptedData_create> commands.
309 when verifying a message normally certificates (if any) included in
310 the message are searched for the signing certificate. With this option
311 only the certificates specified in the B<-certfile> option are used.
312 The supplied certificates can still be used as untrusted CAs however.
314 =item B<-no_signer_cert_verify>
316 do not verify the signers certificate of a signed message.
320 when signing a message the signer's certificate is normally included
321 with this option it is excluded. This will reduce the size of the
322 signed message but the verifier must have a copy of the signers certificate
323 available locally (passed using the B<-certfile> option for example).
327 normally when a message is signed a set of attributes are included which
328 include the signing time and supported symmetric algorithms. With this
329 option they are not included.
333 exclude the list of supported algorithms from signed attributes, other options
334 such as signing time and content type are still included.
338 normally the input message is converted to "canonical" format which is
339 effectively using CR and LF as end of line: as required by the S/MIME
340 specification. When this option is present no translation occurs. This
341 is useful when handling binary data which may not be in MIME format.
345 when signing use ASCII CRLF format canonicalisation. This strips trailing
346 whitespace from all lines, deletes trailing blank lines at EOF and sets
347 the encapsulated content type. This option is normally used with detached
348 content and an output signature format of DER. This option is not normally
349 needed when verifying as it is enabled automatically if the encapsulated
350 content format is detected.
354 when signing a message use opaque signing: this form is more resistant
355 to translation by mail relays but it cannot be read by mail agents that
356 do not support S/MIME. Without this option cleartext signing with
357 the MIME type multipart/signed is used.
359 =item B<-certfile file>
361 allows additional certificates to be specified. When signing these will
362 be included with the message. When verifying these will be searched for
363 the signers certificates. The certificates should be in PEM format.
365 =item B<-certsout file>
367 any certificates contained in the message are written to B<file>.
369 =item B<-signer file>
371 a signing certificate when signing or resigning a message, this option can be
372 used multiple times if more than one signer is required. If a message is being
373 verified then the signers certificates will be written to this file if the
374 verification was successful.
378 when decrypting a message this specifies the recipients certificate. The
379 certificate must match one of the recipients of the message or an error
382 When encrypting a message this option may be used multiple times to specify
383 each recipient. This form B<must> be used if customised parameters are
384 required (for example to specify RSA-OAEP).
388 use subject key identifier to identify certificates instead of issuer name and
389 serial number. The supplied certificate B<must> include a subject key
390 identifier extension. Supported by B<-sign> and B<-encrypt> options.
392 =item B<-receipt_request_all -receipt_request_first>
394 for B<-sign> option include a signed receipt request. Indicate requests should
395 be provided by all recipient or first tier recipients (those mailed directly
396 and not from a mailing list). Ignored it B<-receipt_request_from> is included.
398 =item B<-receipt_request_from emailaddress>
400 for B<-sign> option include a signed receipt request. Add an explicit email
401 address where receipts should be supplied.
403 =item B<-receipt_request_to emailaddress>
405 Add an explicit email address where signed receipts should be sent to. This
406 option B<must> but supplied if a signed receipt it requested.
408 =item B<-receipt_request_print>
410 For the B<-verify> operation print out the contents of any signed receipt
413 =item B<-secretkey key>
415 specify symmetric key to use. The key must be supplied in hex format and be
416 consistent with the algorithm used. Supported by the B<-EncryptedData_encrypt>
417 B<-EncryptedData_decrypt>, B<-encrypt> and B<-decrypt> options. When used
418 with B<-encrypt> or B<-decrypt> the supplied key is used to wrap or unwrap the
419 content encryption key using an AES key in the B<KEKRecipientInfo> type.
421 =item B<-secretkeyid id>
423 the key identifier for the supplied symmetric key for B<KEKRecipientInfo> type.
424 This option B<must> be present if the B<-secretkey> option is used with
425 B<-encrypt>. With B<-decrypt> operations the B<id> is used to locate the
426 relevant key if it is not supplied then an attempt is used to decrypt any
427 B<KEKRecipientInfo> structures.
429 =item B<-econtent_type type>
431 set the encapsulated content type to B<type> if not supplied the B<Data> type
432 is used. The B<type> argument can be any valid OID name in either text or
437 the private key to use when signing or decrypting. This must match the
438 corresponding certificate. If this option is not specified then the
439 private key must be included in the certificate file specified with
440 the B<-recip> or B<-signer> file. When signing this option can be used
441 multiple times to specify successive keys.
443 =item B<-keyopt name:opt>
445 for signing and encryption this option can be used multiple times to
446 set customised parameters for the preceding key or certificate. It can
447 currently be used to set RSA-PSS for signing, RSA-OAEP for encryption
448 or to modify default parameters for ECDH.
452 the private key password source. For more information about the format of B<arg>
453 see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)>.
455 =item B<-rand file(s)>
457 a file or files containing random data used to seed the random number
458 generator, or an EGD socket (see L<RAND_egd(3)>).
459 Multiple files can be specified separated by an OS-dependent character.
460 The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for
465 one or more certificates of message recipients: used when encrypting
468 =item B<-to, -from, -subject>
470 the relevant mail headers. These are included outside the signed
471 portion of a message so they may be included manually. If signing
472 then many S/MIME mail clients check the signers certificate's email
473 address matches that specified in the From: address.
475 =item B<-attime>, B<-check_ss_sig>, B<-crl_check>, B<-crl_check_all>,
476 B<-explicit_policy>, B<-extended_crl>, B<-ignore_critical>, B<-inhibit_any>,
477 B<-inhibit_map>, B<-no_alt_chains>, B<-no_check_time>, B<-partial_chain>, B<-policy>,
478 B<-policy_check>, B<-policy_print>, B<-purpose>, B<-suiteB_128>,
479 B<-suiteB_128_only>, B<-suiteB_192>, B<-trusted_first>, B<-use_deltas>,
480 B<-auth_level>, B<-verify_depth>, B<-verify_email>, B<-verify_hostname>,
481 B<-verify_ip>, B<-verify_name>, B<-x509_strict>
483 Set various certificate chain validation options. See the
484 L<verify(1)> manual page for details.
490 The MIME message must be sent without any blank lines between the
491 headers and the output. Some mail programs will automatically add
492 a blank line. Piping the mail directly to sendmail is one way to
493 achieve the correct format.
495 The supplied message to be signed or encrypted must include the
496 necessary MIME headers or many S/MIME clients wont display it
497 properly (if at all). You can use the B<-text> option to automatically
498 add plain text headers.
500 A "signed and encrypted" message is one where a signed message is
501 then encrypted. This can be produced by encrypting an already signed
502 message: see the examples section.
504 This version of the program only allows one signer per message but it
505 will verify multiple signers on received messages. Some S/MIME clients
506 choke if a message contains multiple signers. It is possible to sign
507 messages "in parallel" by signing an already signed message.
509 The options B<-encrypt> and B<-decrypt> reflect common usage in S/MIME
510 clients. Strictly speaking these process CMS enveloped data: CMS
511 encrypted data is used for other purposes.
513 The B<-resign> option uses an existing message digest when adding a new
514 signer. This means that attributes must be present in at least one existing
515 signer using the same message digest or this operation will fail.
517 The B<-stream> and B<-indef> options enable streaming I/O support.
518 As a result the encoding is BER using indefinite length constructed encoding
519 and no longer DER. Streaming is supported for the B<-encrypt> operation and the
520 B<-sign> operation if the content is not detached.
522 Streaming is always used for the B<-sign> operation with detached data but
523 since the content is no longer part of the CMS structure the encoding
526 If the B<-decrypt> option is used without a recipient certificate then an
527 attempt is made to locate the recipient by trying each potential recipient
528 in turn using the supplied private key. To thwart the MMA attack
529 (Bleichenbacher's attack on PKCS #1 v1.5 RSA padding) all recipients are
530 tried whether they succeed or not and if no recipients match the message
531 is "decrypted" using a random key which will typically output garbage.
532 The B<-debug_decrypt> option can be used to disable the MMA attack protection
533 and return an error if no recipient can be found: this option should be used
534 with caution. For a fuller description see L<CMS_decrypt(3)>).
542 the operation was completely successfully.
546 an error occurred parsing the command options.
550 one of the input files could not be read.
554 an error occurred creating the CMS file or when reading the MIME
559 an error occurred decrypting or verifying the message.
563 the message was verified correctly but an error occurred writing out
564 the signers certificates.
568 =head1 COMPATIBILITY WITH PKCS#7 format.
570 The B<smime> utility can only process the older B<PKCS#7> format. The B<cms>
571 utility supports Cryptographic Message Syntax format. Use of some features
572 will result in messages which cannot be processed by applications which only
573 support the older format. These are detailed below.
575 The use of the B<-keyid> option with B<-sign> or B<-encrypt>.
577 The B<-outform PEM> option uses different headers.
579 The B<-compress> option.
581 The B<-secretkey> option when used with B<-encrypt>.
583 The use of PSS with B<-sign>.
585 The use of OAEP or non-RSA keys with B<-encrypt>.
587 Additionally the B<-EncryptedData_create> and B<-data_create> type cannot
588 be processed by the older B<smime> command.
592 Create a cleartext signed message:
594 openssl cms -sign -in message.txt -text -out mail.msg \
597 Create an opaque signed message
599 openssl cms -sign -in message.txt -text -out mail.msg -nodetach \
602 Create a signed message, include some additional certificates and
603 read the private key from another file:
605 openssl cms -sign -in in.txt -text -out mail.msg \
606 -signer mycert.pem -inkey mykey.pem -certfile mycerts.pem
608 Create a signed message with two signers, use key identifier:
610 openssl cms -sign -in message.txt -text -out mail.msg \
611 -signer mycert.pem -signer othercert.pem -keyid
613 Send a signed message under Unix directly to sendmail, including headers:
615 openssl cms -sign -in in.txt -text -signer mycert.pem \
616 -from steve@openssl.org -to someone@somewhere \
617 -subject "Signed message" | sendmail someone@somewhere
619 Verify a message and extract the signer's certificate if successful:
621 openssl cms -verify -in mail.msg -signer user.pem -out signedtext.txt
623 Send encrypted mail using triple DES:
625 openssl cms -encrypt -in in.txt -from steve@openssl.org \
626 -to someone@somewhere -subject "Encrypted message" \
627 -des3 user.pem -out mail.msg
629 Sign and encrypt mail:
631 openssl cms -sign -in ml.txt -signer my.pem -text \
632 | openssl cms -encrypt -out mail.msg \
633 -from steve@openssl.org -to someone@somewhere \
634 -subject "Signed and Encrypted message" -des3 user.pem
636 Note: the encryption command does not include the B<-text> option because the
637 message being encrypted already has MIME headers.
641 openssl cms -decrypt -in mail.msg -recip mycert.pem -inkey key.pem
643 The output from Netscape form signing is a PKCS#7 structure with the
644 detached signature format. You can use this program to verify the
645 signature by line wrapping the base64 encoded structure and surrounding
648 -----BEGIN PKCS7-----
651 and using the command,
653 openssl cms -verify -inform PEM -in signature.pem -content content.txt
655 alternatively you can base64 decode the signature and use
657 openssl cms -verify -inform DER -in signature.der -content content.txt
659 Create an encrypted message using 128 bit Camellia:
661 openssl cms -encrypt -in plain.txt -camellia128 -out mail.msg cert.pem
663 Add a signer to an existing message:
665 openssl cms -resign -in mail.msg -signer newsign.pem -out mail2.msg
667 Sign mail using RSA-PSS:
669 openssl cms -sign -in message.txt -text -out mail.msg \
670 -signer mycert.pem -keyopt rsa_padding_mode:pss
672 Create encrypted mail using RSA-OAEP:
674 openssl cms -encrypt -in plain.txt -out mail.msg \
675 -recip cert.pem -keyopt rsa_padding_mode:oaep
677 Use SHA256 KDF with an ECDH certificate:
679 openssl cms -encrypt -in plain.txt -out mail.msg \
680 -recip ecdhcert.pem -keyopt ecdh_kdf_md:sha256
684 The MIME parser isn't very clever: it seems to handle most messages that I've
685 thrown at it but it may choke on others.
687 The code currently will only write out the signer's certificate to a file: if
688 the signer has a separate encryption certificate this must be manually
689 extracted. There should be some heuristic that determines the correct
690 encryption certificate.
692 Ideally a database should be maintained of a certificates for each email
695 The code doesn't currently take note of the permitted symmetric encryption
696 algorithms as supplied in the SMIMECapabilities signed attribute. this means the
697 user has to manually include the correct encryption algorithm. It should store
698 the list of permitted ciphers in a database and only use those.
700 No revocation checking is done on the signer's certificate.
704 The use of multiple B<-signer> options and the B<-resign> command were first
705 added in OpenSSL 1.0.0
707 The B<keyopt> option was first added in OpenSSL 1.1.0
709 The use of B<-recip> to specify the recipient when encrypting mail was first
710 added to OpenSSL 1.1.0
712 Support for RSA-OAEP and RSA-PSS was first added to OpenSSL 1.1.0.
714 The use of non-RSA keys with B<-encrypt> and B<-decrypt> was first added
717 The -no_alt_chains options was first added to OpenSSL 1.1.0.