22 [B<-EncryptedData_encrypt>]
24 [B<-verify_receipt receipt>]
26 [B<-inform SMIME|PEM|DER>]
27 [B<-rctform SMIME|PEM|DER>]
29 [B<-outform SMIME|PEM|DER>]
30 [B<-stream -indef -noindef>]
32 [B<-content filename>]
38 [B<-attime timestamp>]
58 [B<-verify_depth num>]
59 [B<-verify_email email>]
60 [B<-verify_hostname hostname>]
62 [B<-verify_name name>]
67 [B<-no_signer_cert_verify>]
79 [B<-receipt_request_all -receipt_request_first>]
80 [B<-receipt_request_from emailaddress>]
81 [B<-receipt_request_to emailaddress>]
82 [B<-receipt_request_print>]
85 [B<-econtent_type type>]
87 [B<-keyopt name:parameter>]
98 The B<cms> command handles S/MIME v3.1 mail. It can encrypt, decrypt, sign and
99 verify, compress and uncompress S/MIME messages.
101 =head1 COMMAND OPTIONS
103 There are fourteen operation options that set the type of operation to be
104 performed. The meaning of the other options varies according to the operation
111 encrypt mail for the given recipient certificates. Input file is the message
112 to be encrypted. The output file is the encrypted mail in MIME format. The
113 actual CMS type is <B>EnvelopedData<B>.
117 decrypt mail using the supplied certificate and private key. Expects an
118 encrypted mail message in MIME format for the input file. The decrypted mail
119 is written to the output file.
121 =item B<-debug_decrypt>
123 this option sets the B<CMS_DEBUG_DECRYPT> flag. This option should be used
124 with caution: see the notes section below.
128 sign mail using the supplied certificate and private key. Input file is
129 the message to be signed. The signed message in MIME format is written
134 verify signed mail. Expects a signed mail message on input and outputs
135 the signed data. Both clear text and opaque signing is supported.
139 takes an input message and writes out a PEM encoded CMS structure.
143 resign a message: take an existing message and one or more new signers.
145 =item B<-data_create>
147 Create a CMS B<Data> type.
151 B<Data> type and output the content.
153 =item B<-digest_create>
155 Create a CMS B<DigestedData> type.
157 =item B<-digest_verify>
159 Verify a CMS B<DigestedData> type and output the content.
163 Create a CMS B<CompressedData> type. OpenSSL must be compiled with B<zlib>
164 support for this option to work, otherwise it will output an error.
168 Uncompress a CMS B<CompressedData> type and output the content. OpenSSL must be
169 compiled with B<zlib> support for this option to work, otherwise it will
172 =item B<-EncryptedData_encrypt>
174 Encrypt content using supplied symmetric key and algorithm using a CMS
175 B<EncrytedData> type and output the content.
177 =item B<-sign_receipt>
179 Generate and output a signed receipt for the supplied message. The input
180 message B<must> contain a signed receipt request. Functionality is otherwise
181 similar to the B<-sign> operation.
183 =item B<-verify_receipt receipt>
185 Verify a signed receipt in filename B<receipt>. The input message B<must>
186 contain the original receipt request. Functionality is otherwise similar
187 to the B<-verify> operation.
189 =item B<-in filename>
191 the input message to be encrypted or signed or the message to be decrypted
194 =item B<-inform SMIME|PEM|DER>
196 this specifies the input format for the CMS structure. The default
197 is B<SMIME> which reads an S/MIME format message. B<PEM> and B<DER>
198 format change this to expect PEM and DER format CMS structures
199 instead. This currently only affects the input format of the CMS
200 structure, if no CMS structure is being input (for example with
201 B<-encrypt> or B<-sign>) this option has no effect.
203 =item B<-rctform SMIME|PEM|DER>
205 specify the format for a signed receipt for use with the B<-receipt_verify>
208 =item B<-out filename>
210 the message text that has been decrypted or verified or the output MIME
211 format message that has been signed or verified.
213 =item B<-outform SMIME|PEM|DER>
215 this specifies the output format for the CMS structure. The default
216 is B<SMIME> which writes an S/MIME format message. B<PEM> and B<DER>
217 format change this to write PEM and DER format CMS structures
218 instead. This currently only affects the output format of the CMS
219 structure, if no CMS structure is being output (for example with
220 B<-verify> or B<-decrypt>) this option has no effect.
222 =item B<-stream -indef -noindef>
224 the B<-stream> and B<-indef> options are equivalent and enable streaming I/O
225 for encoding operations. This permits single pass processing of data without
226 the need to hold the entire contents in memory, potentially supporting very
227 large files. Streaming is automatically set for S/MIME signing with detached
228 data if the output format is B<SMIME> it is currently off by default for all
233 disable streaming I/O where it would produce and indefinite length constructed
234 encoding. This option currently has no effect. In future streaming will be
235 enabled by default on all relevant operations and this option will disable it.
237 =item B<-content filename>
239 This specifies a file containing the detached content, this is only
240 useful with the B<-verify> command. This is only usable if the CMS
241 structure is using the detached signature form where the content is
242 not included. This option will override any content if the input format
243 is S/MIME and it uses the multipart/signed MIME content type.
247 this option adds plain text (text/plain) MIME headers to the supplied
248 message if encrypting or signing. If decrypting or verifying it strips
249 off text headers: if the decrypted or verified message is not of MIME
250 type text/plain then an error occurs.
254 for the B<-cmsout> operation do not output the parsed CMS structure. This
255 is useful when combined with the B<-print> option or if the syntax of the CMS
256 structure is being checked.
260 for the B<-cmsout> operation print out all fields of the CMS structure. This
261 is mainly useful for testing purposes.
263 =item B<-CAfile file>
265 a file containing trusted CA certificates, only used with B<-verify>.
269 a directory containing trusted CA certificates, only used with
270 B<-verify>. This directory must be a standard certificate directory: that
271 is a hash of each subject name (using B<x509 -hash>) should be linked
276 digest algorithm to use when signing or resigning. If not present then the
277 default digest algorithm for the signing key will be used (usually SHA1).
281 the encryption algorithm to use. For example triple DES (168 bits) - B<-des3>
282 or 256 bit AES - B<-aes256>. Any standard algorithm name (as used by the
283 EVP_get_cipherbyname() function) can also be used preceded by a dash, for
284 example B<-aes_128_cbc>. See L<B<enc>|enc(1)> for a list of ciphers
285 supported by your version of OpenSSL.
287 If not specified triple DES is used. Only used with B<-encrypt> and
288 B<-EncryptedData_create> commands.
292 when verifying a message normally certificates (if any) included in
293 the message are searched for the signing certificate. With this option
294 only the certificates specified in the B<-certfile> option are used.
295 The supplied certificates can still be used as untrusted CAs however.
297 =item B<-no_signer_cert_verify>
299 do not verify the signers certificate of a signed message.
303 when signing a message the signer's certificate is normally included
304 with this option it is excluded. This will reduce the size of the
305 signed message but the verifier must have a copy of the signers certificate
306 available locally (passed using the B<-certfile> option for example).
310 normally when a message is signed a set of attributes are included which
311 include the signing time and supported symmetric algorithms. With this
312 option they are not included.
316 exclude the list of supported algorithms from signed attributes, other options
317 such as signing time and content type are still included.
321 normally the input message is converted to "canonical" format which is
322 effectively using CR and LF as end of line: as required by the S/MIME
323 specification. When this option is present no translation occurs. This
324 is useful when handling binary data which may not be in MIME format.
328 when signing use ASCII CRLF format canonicalisation. This strips trailing
329 whitespace from all lines, deletes trailing blank lines at EOF and sets
330 the encapsulated content type. This option is normally used with detached
331 content and an output signature format of DER. This option is not normally
332 needed when verifying as it is enabled automatically if the encapsulated
333 content format is detected.
337 when signing a message use opaque signing: this form is more resistant
338 to translation by mail relays but it cannot be read by mail agents that
339 do not support S/MIME. Without this option cleartext signing with
340 the MIME type multipart/signed is used.
342 =item B<-certfile file>
344 allows additional certificates to be specified. When signing these will
345 be included with the message. When verifying these will be searched for
346 the signers certificates. The certificates should be in PEM format.
348 =item B<-certsout file>
350 any certificates contained in the message are written to B<file>.
352 =item B<-signer file>
354 a signing certificate when signing or resigning a message, this option can be
355 used multiple times if more than one signer is required. If a message is being
356 verified then the signers certificates will be written to this file if the
357 verification was successful.
361 when decrypting a message this specifies the recipients certificate. The
362 certificate must match one of the recipients of the message or an error
365 When encrypting a message this option may be used multiple times to specify
366 each recipient. This form B<must> be used if customised parameters are
367 required (for example to specify RSA-OAEP).
371 use subject key identifier to identify certificates instead of issuer name and
372 serial number. The supplied certificate B<must> include a subject key
373 identifier extension. Supported by B<-sign> and B<-encrypt> options.
375 =item B<-receipt_request_all -receipt_request_first>
377 for B<-sign> option include a signed receipt request. Indicate requests should
378 be provided by all receipient or first tier recipients (those mailed directly
379 and not from a mailing list). Ignored it B<-receipt_request_from> is included.
381 =item B<-receipt_request_from emailaddress>
383 for B<-sign> option include a signed receipt request. Add an explicit email
384 address where receipts should be supplied.
386 =item B<-receipt_request_to emailaddress>
388 Add an explicit email address where signed receipts should be sent to. This
389 option B<must> but supplied if a signed receipt it requested.
391 =item B<-receipt_request_print>
393 For the B<-verify> operation print out the contents of any signed receipt
396 =item B<-secretkey key>
398 specify symmetric key to use. The key must be supplied in hex format and be
399 consistent with the algorithm used. Supported by the B<-EncryptedData_encrypt>
400 B<-EncrryptedData_decrypt>, B<-encrypt> and B<-decrypt> options. When used
401 with B<-encrypt> or B<-decrypt> the supplied key is used to wrap or unwrap the
402 content encryption key using an AES key in the B<KEKRecipientInfo> type.
404 =item B<-secretkeyid id>
406 the key identifier for the supplied symmetric key for B<KEKRecipientInfo> type.
407 This option B<must> be present if the B<-secretkey> option is used with
408 B<-encrypt>. With B<-decrypt> operations the B<id> is used to locate the
409 relevant key if it is not supplied then an attempt is used to decrypt any
410 B<KEKRecipientInfo> structures.
412 =item B<-econtent_type type>
414 set the encapsulated content type to B<type> if not supplied the B<Data> type
415 is used. The B<type> argument can be any valid OID name in either text or
420 the private key to use when signing or decrypting. This must match the
421 corresponding certificate. If this option is not specified then the
422 private key must be included in the certificate file specified with
423 the B<-recip> or B<-signer> file. When signing this option can be used
424 multiple times to specify successive keys.
426 =item B<-keyopt name:opt>
428 for signing and encryption this option can be used multiple times to
429 set customised parameters for the preceding key or certificate. It can
430 currently be used to set RSA-PSS for signing, RSA-OAEP for encryption
431 or to modify default parameters for ECDH.
435 the private key password source. For more information about the format of B<arg>
436 see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)|openssl(1)>.
438 =item B<-rand file(s)>
440 a file or files containing random data used to seed the random number
441 generator, or an EGD socket (see L<RAND_egd(3)|RAND_egd(3)>).
442 Multiple files can be specified separated by a OS-dependent character.
443 The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for
448 one or more certificates of message recipients: used when encrypting
451 =item B<-to, -from, -subject>
453 the relevant mail headers. These are included outside the signed
454 portion of a message so they may be included manually. If signing
455 then many S/MIME mail clients check the signers certificate's email
456 address matches that specified in the From: address.
458 =item B<-attime>, B<-check_ss_sig>, B<-crl_check>, B<-crl_check_all>,
459 B<explicit_policy>, B<-extended_crl>, B<-ignore_critical>, B<-inhibit_any>,
460 B<-inhibit_map>, B<-issuer_checks>, B<-partial_chain>, B<-policy>,
461 B<-policy_check>, B<-policy_print>, B<-purpose>, B<-suiteB_128>,
462 B<-suiteB_128_only>, B<-suiteB_192>, B<-trusted_first>, B<-use_deltas>,
463 B<-verify_depth>, B<-verify_email>, B<-verify_hostname>, B<-verify_ip>,
464 B<-verify_name>, B<-x509_strict>
466 Set various certificate chain valiadition options. See the
467 L<B<verify>|verify(1)> manual page for details.
473 The MIME message must be sent without any blank lines between the
474 headers and the output. Some mail programs will automatically add
475 a blank line. Piping the mail directly to sendmail is one way to
476 achieve the correct format.
478 The supplied message to be signed or encrypted must include the
479 necessary MIME headers or many S/MIME clients wont display it
480 properly (if at all). You can use the B<-text> option to automatically
481 add plain text headers.
483 A "signed and encrypted" message is one where a signed message is
484 then encrypted. This can be produced by encrypting an already signed
485 message: see the examples section.
487 This version of the program only allows one signer per message but it
488 will verify multiple signers on received messages. Some S/MIME clients
489 choke if a message contains multiple signers. It is possible to sign
490 messages "in parallel" by signing an already signed message.
492 The options B<-encrypt> and B<-decrypt> reflect common usage in S/MIME
493 clients. Strictly speaking these process CMS enveloped data: CMS
494 encrypted data is used for other purposes.
496 The B<-resign> option uses an existing message digest when adding a new
497 signer. This means that attributes must be present in at least one existing
498 signer using the same message digest or this operation will fail.
500 The B<-stream> and B<-indef> options enable experimental streaming I/O support.
501 As a result the encoding is BER using indefinite length constructed encoding
502 and no longer DER. Streaming is supported for the B<-encrypt> operation and the
503 B<-sign> operation if the content is not detached.
505 Streaming is always used for the B<-sign> operation with detached data but
506 since the content is no longer part of the CMS structure the encoding
509 If the B<-decrypt> option is used without a recipient certificate then an
510 attempt is made to locate the recipient by trying each potential recipient
511 in turn using the supplied private key. To thwart the MMA attack
512 (Bleichenbacher's attack on PKCS #1 v1.5 RSA padding) all recipients are
513 tried whether they succeed or not and if no recipients match the message
514 is "decrypted" using a random key which will typically output garbage.
515 The B<-debug_decrypt> option can be used to disable the MMA attack protection
516 and return an error if no recipient can be found: this option should be used
517 with caution. For a fuller description see L<CMS_decrypt(3)|CMS_decrypt(3)>).
525 the operation was completely successfully.
529 an error occurred parsing the command options.
533 one of the input files could not be read.
537 an error occurred creating the CMS file or when reading the MIME
542 an error occurred decrypting or verifying the message.
546 the message was verified correctly but an error occurred writing out
547 the signers certificates.
551 =head1 COMPATIBILITY WITH PKCS#7 format.
553 The B<smime> utility can only process the older B<PKCS#7> format. The B<cms>
554 utility supports Cryptographic Message Syntax format. Use of some features
555 will result in messages which cannot be processed by applications which only
556 support the older format. These are detailed below.
558 The use of the B<-keyid> option with B<-sign> or B<-encrypt>.
560 The B<-outform PEM> option uses different headers.
562 The B<-compress> option.
564 The B<-secretkey> option when used with B<-encrypt>.
566 The use of PSS with B<-sign>.
568 The use of OAEP or non-RSA keys with B<-encrypt>.
570 Additionally the B<-EncryptedData_create> and B<-data_create> type cannot
571 be processed by the older B<smime> command.
575 Create a cleartext signed message:
577 openssl cms -sign -in message.txt -text -out mail.msg \
580 Create an opaque signed message
582 openssl cms -sign -in message.txt -text -out mail.msg -nodetach \
585 Create a signed message, include some additional certificates and
586 read the private key from another file:
588 openssl cms -sign -in in.txt -text -out mail.msg \
589 -signer mycert.pem -inkey mykey.pem -certfile mycerts.pem
591 Create a signed message with two signers, use key identifier:
593 openssl cms -sign -in message.txt -text -out mail.msg \
594 -signer mycert.pem -signer othercert.pem -keyid
596 Send a signed message under Unix directly to sendmail, including headers:
598 openssl cms -sign -in in.txt -text -signer mycert.pem \
599 -from steve@openssl.org -to someone@somewhere \
600 -subject "Signed message" | sendmail someone@somewhere
602 Verify a message and extract the signer's certificate if successful:
604 openssl cms -verify -in mail.msg -signer user.pem -out signedtext.txt
606 Send encrypted mail using triple DES:
608 openssl cms -encrypt -in in.txt -from steve@openssl.org \
609 -to someone@somewhere -subject "Encrypted message" \
610 -des3 user.pem -out mail.msg
612 Sign and encrypt mail:
614 openssl cms -sign -in ml.txt -signer my.pem -text \
615 | openssl cms -encrypt -out mail.msg \
616 -from steve@openssl.org -to someone@somewhere \
617 -subject "Signed and Encrypted message" -des3 user.pem
619 Note: the encryption command does not include the B<-text> option because the
620 message being encrypted already has MIME headers.
624 openssl cms -decrypt -in mail.msg -recip mycert.pem -inkey key.pem
626 The output from Netscape form signing is a PKCS#7 structure with the
627 detached signature format. You can use this program to verify the
628 signature by line wrapping the base64 encoded structure and surrounding
631 -----BEGIN PKCS7-----
634 and using the command,
636 openssl cms -verify -inform PEM -in signature.pem -content content.txt
638 alternatively you can base64 decode the signature and use
640 openssl cms -verify -inform DER -in signature.der -content content.txt
642 Create an encrypted message using 128 bit Camellia:
644 openssl cms -encrypt -in plain.txt -camellia128 -out mail.msg cert.pem
646 Add a signer to an existing message:
648 openssl cms -resign -in mail.msg -signer newsign.pem -out mail2.msg
650 Sign mail using RSA-PSS:
652 openssl cms -sign -in message.txt -text -out mail.msg \
653 -signer mycert.pem -keyopt rsa_padding_mode:pss
655 Create encrypted mail using RSA-OAEP:
657 openssl cms -encrypt -in plain.txt -out mail.msg \
658 -recip cert.pem -keyopt rsa_padding_mode:oaep
660 Use SHA256 KDF with an ECDH certificate:
662 openssl cms -encrypt -in plain.txt -out mail.msg \
663 -recip ecdhcert.pem -keyopt ecdh_kdf_md:sha256
667 The MIME parser isn't very clever: it seems to handle most messages that I've
668 thrown at it but it may choke on others.
670 The code currently will only write out the signer's certificate to a file: if
671 the signer has a separate encryption certificate this must be manually
672 extracted. There should be some heuristic that determines the correct
673 encryption certificate.
675 Ideally a database should be maintained of a certificates for each email
678 The code doesn't currently take note of the permitted symmetric encryption
679 algorithms as supplied in the SMIMECapabilities signed attribute. this means the
680 user has to manually include the correct encryption algorithm. It should store
681 the list of permitted ciphers in a database and only use those.
683 No revocation checking is done on the signer's certificate.
687 The use of multiple B<-signer> options and the B<-resign> command were first
688 added in OpenSSL 1.0.0
690 The B<keyopt> option was first added in OpenSSL 1.1.0
692 The use of B<-recip> to specify the recipient when encrypting mail was first
693 added to OpenSSL 1.1.0
695 Support for RSA-OAEP and RSA-PSS was first added to OpenSSL 1.1.0.
697 The use of non-RSA keys with B<-encrypt> and B<-decrypt> was first added