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>]
42 [B<-no_signer_cert_verify>]
54 [B<-receipt_request_all -receipt_request_first>]
55 [B<-receipt_request_from emailaddress>]
56 [B<-receipt_request_to emailaddress>]
57 [B<-receipt_request_print>]
60 [B<-econtent_type type>]
62 [B<-keyopt name:parameter>]
73 The B<cms> command handles S/MIME v3.1 mail. It can encrypt, decrypt, sign and
74 verify, compress and uncompress S/MIME messages.
76 =head1 COMMAND OPTIONS
78 There are fourteen operation options that set the type of operation to be
79 performed. The meaning of the other options varies according to the operation
86 encrypt mail for the given recipient certificates. Input file is the message
87 to be encrypted. The output file is the encrypted mail in MIME format. The
88 actual CMS type is <B>EnvelopedData<B>.
92 decrypt mail using the supplied certificate and private key. Expects an
93 encrypted mail message in MIME format for the input file. The decrypted mail
94 is written to the output file.
96 =item B<-debug_decrypt>
98 this option sets the B<CMS_DEBUG_DECRYPT> flag. This option should be used
99 with caution: see the notes section below.
103 sign mail using the supplied certificate and private key. Input file is
104 the message to be signed. The signed message in MIME format is written
109 verify signed mail. Expects a signed mail message on input and outputs
110 the signed data. Both clear text and opaque signing is supported.
114 takes an input message and writes out a PEM encoded CMS structure.
118 resign a message: take an existing message and one or more new signers.
120 =item B<-data_create>
122 Create a CMS B<Data> type.
126 B<Data> type and output the content.
128 =item B<-digest_create>
130 Create a CMS B<DigestedData> type.
132 =item B<-digest_verify>
134 Verify a CMS B<DigestedData> type and output the content.
138 Create a CMS B<CompressedData> type. OpenSSL must be compiled with B<zlib>
139 support for this option to work, otherwise it will output an error.
143 Uncompress a CMS B<CompressedData> type and output the content. OpenSSL must be
144 compiled with B<zlib> support for this option to work, otherwise it will
147 =item B<-EncryptedData_encrypt>
149 Encrypt suppled content using supplied symmetric key and algorithm using a CMS
150 B<EncrytedData> type and output the content.
152 =item B<-sign_receipt>
154 Generate and output a signed receipt for the supplied message. The input
155 message B<must> contain a signed receipt request. Functionality is otherwise
156 similar to the B<-sign> operation.
158 =item B<-verify_receipt receipt>
160 Verify a signed receipt in filename B<receipt>. The input message B<must>
161 contain the original receipt request. Functionality is otherwise similar
162 to the B<-verify> operation.
164 =item B<-in filename>
166 the input message to be encrypted or signed or the message to be decrypted
169 =item B<-inform SMIME|PEM|DER>
171 this specifies the input format for the CMS structure. The default
172 is B<SMIME> which reads an S/MIME format message. B<PEM> and B<DER>
173 format change this to expect PEM and DER format CMS structures
174 instead. This currently only affects the input format of the CMS
175 structure, if no CMS structure is being input (for example with
176 B<-encrypt> or B<-sign>) this option has no effect.
178 =item B<-rctform SMIME|PEM|DER>
180 specify the format for a signed receipt for use with the B<-receipt_verify>
183 =item B<-out filename>
185 the message text that has been decrypted or verified or the output MIME
186 format message that has been signed or verified.
188 =item B<-outform SMIME|PEM|DER>
190 this specifies the output format for the CMS structure. The default
191 is B<SMIME> which writes an S/MIME format message. B<PEM> and B<DER>
192 format change this to write PEM and DER format CMS structures
193 instead. This currently only affects the output format of the CMS
194 structure, if no CMS structure is being output (for example with
195 B<-verify> or B<-decrypt>) this option has no effect.
197 =item B<-stream -indef -noindef>
199 the B<-stream> and B<-indef> options are equivalent and enable streaming I/O
200 for encoding operations. This permits single pass processing of data without
201 the need to hold the entire contents in memory, potentially supporting very
202 large files. Streaming is automatically set for S/MIME signing with detached
203 data if the output format is B<SMIME> it is currently off by default for all
208 disable streaming I/O where it would produce and indefinite length constructed
209 encoding. This option currently has no effect. In future streaming will be
210 enabled by default on all relevant operations and this option will disable it.
212 =item B<-content filename>
214 This specifies a file containing the detached content, this is only
215 useful with the B<-verify> command. This is only usable if the CMS
216 structure is using the detached signature form where the content is
217 not included. This option will override any content if the input format
218 is S/MIME and it uses the multipart/signed MIME content type.
222 this option adds plain text (text/plain) MIME headers to the supplied
223 message if encrypting or signing. If decrypting or verifying it strips
224 off text headers: if the decrypted or verified message is not of MIME
225 type text/plain then an error occurs.
229 for the B<-cmsout> operation do not output the parsed CMS structure. This
230 is useful when combined with the B<-print> option or if the syntax of the CMS
231 structure is being checked.
235 for the B<-cmsout> operation print out all fields of the CMS structure. This
236 is mainly useful for testing purposes.
238 =item B<-CAfile file>
240 a file containing trusted CA certificates, only used with B<-verify>.
244 a directory containing trusted CA certificates, only used with
245 B<-verify>. This directory must be a standard certificate directory: that
246 is a hash of each subject name (using B<x509 -hash>) should be linked
251 digest algorithm to use when signing or resigning. If not present then the
252 default digest algorithm for the signing key will be used (usually SHA1).
256 the encryption algorithm to use. For example triple DES (168 bits) - B<-des3>
257 or 256 bit AES - B<-aes256>. Any standard algorithm name (as used by the
258 EVP_get_cipherbyname() function) can also be used preceded by a dash, for
259 example B<-aes_128_cbc>. See L<B<enc>|enc(1)> for a list of ciphers
260 supported by your version of OpenSSL.
262 If not specified triple DES is used. Only used with B<-encrypt> and
263 B<-EncryptedData_create> commands.
267 when verifying a message normally certificates (if any) included in
268 the message are searched for the signing certificate. With this option
269 only the certificates specified in the B<-certfile> option are used.
270 The supplied certificates can still be used as untrusted CAs however.
272 =item B<-no_signer_cert_verify>
274 do not verify the signers certificate of a signed message.
278 when signing a message the signer's certificate is normally included
279 with this option it is excluded. This will reduce the size of the
280 signed message but the verifier must have a copy of the signers certificate
281 available locally (passed using the B<-certfile> option for example).
285 normally when a message is signed a set of attributes are included which
286 include the signing time and supported symmetric algorithms. With this
287 option they are not included.
291 exclude the list of supported algorithms from signed attributes, other options
292 such as signing time and content type are still included.
296 normally the input message is converted to "canonical" format which is
297 effectively using CR and LF as end of line: as required by the S/MIME
298 specification. When this option is present no translation occurs. This
299 is useful when handling binary data which may not be in MIME format.
303 when signing use ASCII CRLF format canonicalisation. This strips trailing
304 whitespace from all lines, deletes trailing blank lines at EOF and sets
305 the encapsulated content type. This option is normally used with detached
306 content and an output signature format of DER. This option is not normally
307 needed when verifying as it is enabled automatically if the encapsulated
308 content format is detected.
312 when signing a message use opaque signing: this form is more resistant
313 to translation by mail relays but it cannot be read by mail agents that
314 do not support S/MIME. Without this option cleartext signing with
315 the MIME type multipart/signed is used.
317 =item B<-certfile file>
319 allows additional certificates to be specified. When signing these will
320 be included with the message. When verifying these will be searched for
321 the signers certificates. The certificates should be in PEM format.
323 =item B<-certsout file>
325 any certificates contained in the message are written to B<file>.
327 =item B<-signer file>
329 a signing certificate when signing or resigning a message, this option can be
330 used multiple times if more than one signer is required. If a message is being
331 verified then the signers certificates will be written to this file if the
332 verification was successful.
336 when decrypting a message this specifies the recipients certificate. The
337 certificate must match one of the recipients of the message or an error
340 When encrypting a message this option may be used multiple times to specify
341 each recipient. This form B<must> be used if customised parameters are
342 required (for example to specify RSA-OAEP).
346 use subject key identifier to identify certificates instead of issuer name and
347 serial number. The supplied certificate B<must> include a subject key
348 identifier extension. Supported by B<-sign> and B<-encrypt> options.
350 =item B<-receipt_request_all -receipt_request_first>
352 for B<-sign> option include a signed receipt request. Indicate requests should
353 be provided by all receipient or first tier recipients (those mailed directly
354 and not from a mailing list). Ignored it B<-receipt_request_from> is included.
356 =item B<-receipt_request_from emailaddress>
358 for B<-sign> option include a signed receipt request. Add an explicit email
359 address where receipts should be supplied.
361 =item B<-receipt_request_to emailaddress>
363 Add an explicit email address where signed receipts should be sent to. This
364 option B<must> but supplied if a signed receipt it requested.
366 =item B<-receipt_request_print>
368 For the B<-verify> operation print out the contents of any signed receipt
371 =item B<-secretkey key>
373 specify symmetric key to use. The key must be supplied in hex format and be
374 consistent with the algorithm used. Supported by the B<-EncryptedData_encrypt>
375 B<-EncrryptedData_decrypt>, B<-encrypt> and B<-decrypt> options. When used
376 with B<-encrypt> or B<-decrypt> the supplied key is used to wrap or unwrap the
377 content encryption key using an AES key in the B<KEKRecipientInfo> type.
379 =item B<-secretkeyid id>
381 the key identifier for the supplied symmetric key for B<KEKRecipientInfo> type.
382 This option B<must> be present if the B<-secretkey> option is used with
383 B<-encrypt>. With B<-decrypt> operations the B<id> is used to locate the
384 relevant key if it is not supplied then an attempt is used to decrypt any
385 B<KEKRecipientInfo> structures.
387 =item B<-econtent_type type>
389 set the encapsulated content type to B<type> if not supplied the B<Data> type
390 is used. The B<type> argument can be any valid OID name in either text or
395 the private key to use when signing or decrypting. This must match the
396 corresponding certificate. If this option is not specified then the
397 private key must be included in the certificate file specified with
398 the B<-recip> or B<-signer> file. When signing this option can be used
399 multiple times to specify successive keys.
401 =item B<-keyopt name:opt>
403 for signing and encryption this option can be used multiple times to
404 set customised parameters for the preceding key or certificate. It can
405 currently be used to set RSA-PSS for signing, RSA-OAEP for encryption
406 or to modify default parameters for ECDH.
410 the private key password source. For more information about the format of B<arg>
411 see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)|openssl(1)>.
413 =item B<-rand file(s)>
415 a file or files containing random data used to seed the random number
416 generator, or an EGD socket (see L<RAND_egd(3)|RAND_egd(3)>).
417 Multiple files can be specified separated by a OS-dependent character.
418 The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for
423 one or more certificates of message recipients: used when encrypting
426 =item B<-to, -from, -subject>
428 the relevant mail headers. These are included outside the signed
429 portion of a message so they may be included manually. If signing
430 then many S/MIME mail clients check the signers certificate's email
431 address matches that specified in the From: address.
433 =item B<-purpose, -ignore_critical, -issuer_checks, -crl_check, -crl_check_all, -policy_check, -extended_crl, -x509_strict, -policy -check_ss_sig, -trusted_first>
435 Set various certificate chain valiadition options. See the
436 L<B<verify>|verify(1)> manual page for details.
442 The MIME message must be sent without any blank lines between the
443 headers and the output. Some mail programs will automatically add
444 a blank line. Piping the mail directly to sendmail is one way to
445 achieve the correct format.
447 The supplied message to be signed or encrypted must include the
448 necessary MIME headers or many S/MIME clients wont display it
449 properly (if at all). You can use the B<-text> option to automatically
450 add plain text headers.
452 A "signed and encrypted" message is one where a signed message is
453 then encrypted. This can be produced by encrypting an already signed
454 message: see the examples section.
456 This version of the program only allows one signer per message but it
457 will verify multiple signers on received messages. Some S/MIME clients
458 choke if a message contains multiple signers. It is possible to sign
459 messages "in parallel" by signing an already signed message.
461 The options B<-encrypt> and B<-decrypt> reflect common usage in S/MIME
462 clients. Strictly speaking these process CMS enveloped data: CMS
463 encrypted data is used for other purposes.
465 The B<-resign> option uses an existing message digest when adding a new
466 signer. This means that attributes must be present in at least one existing
467 signer using the same message digest or this operation will fail.
469 The B<-stream> and B<-indef> options enable experimental streaming I/O support.
470 As a result the encoding is BER using indefinite length constructed encoding
471 and no longer DER. Streaming is supported for the B<-encrypt> operation and the
472 B<-sign> operation if the content is not detached.
474 Streaming is always used for the B<-sign> operation with detached data but
475 since the content is no longer part of the CMS structure the encoding
478 If the B<-decrypt> option is used without a recipient certificate then an
479 attempt is made to locate the recipient by trying each potential recipient
480 in turn using the supplied private key. To thwart the MMA attack
481 (Bleichenbacher's attack on PKCS #1 v1.5 RSA padding) all recipients are
482 tried whether they succeed or not and if no recipients match the message
483 is "decrypted" using a random key which will typically output garbage.
484 The B<-debug_decrypt> option can be used to disable the MMA attack protection
485 and return an error if no recipient can be found: this option should be used
486 with caution. For a fuller description see L<CMS_decrypt(3)|CMS_decrypt(3)>).
494 the operation was completely successfully.
498 an error occurred parsing the command options.
502 one of the input files could not be read.
506 an error occurred creating the CMS file or when reading the MIME
511 an error occurred decrypting or verifying the message.
515 the message was verified correctly but an error occurred writing out
516 the signers certificates.
520 =head1 COMPATIBILITY WITH PKCS#7 format.
522 The B<smime> utility can only process the older B<PKCS#7> format. The B<cms>
523 utility supports Cryptographic Message Syntax format. Use of some features
524 will result in messages which cannot be processed by applications which only
525 support the older format. These are detailed below.
527 The use of the B<-keyid> option with B<-sign> or B<-encrypt>.
529 The B<-outform PEM> option uses different headers.
531 The B<-compress> option.
533 The B<-secretkey> option when used with B<-encrypt>.
535 The use of PSS with B<-sign>.
537 The use of OAEP or non-RSA keys with B<-encrypt>.
539 Additionally the B<-EncryptedData_create> and B<-data_create> type cannot
540 be processed by the older B<smime> command.
544 Create a cleartext signed message:
546 openssl cms -sign -in message.txt -text -out mail.msg \
549 Create an opaque signed message
551 openssl cms -sign -in message.txt -text -out mail.msg -nodetach \
554 Create a signed message, include some additional certificates and
555 read the private key from another file:
557 openssl cms -sign -in in.txt -text -out mail.msg \
558 -signer mycert.pem -inkey mykey.pem -certfile mycerts.pem
560 Create a signed message with two signers, use key identifier:
562 openssl cms -sign -in message.txt -text -out mail.msg \
563 -signer mycert.pem -signer othercert.pem -keyid
565 Send a signed message under Unix directly to sendmail, including headers:
567 openssl cms -sign -in in.txt -text -signer mycert.pem \
568 -from steve@openssl.org -to someone@somewhere \
569 -subject "Signed message" | sendmail someone@somewhere
571 Verify a message and extract the signer's certificate if successful:
573 openssl cms -verify -in mail.msg -signer user.pem -out signedtext.txt
575 Send encrypted mail using triple DES:
577 openssl cms -encrypt -in in.txt -from steve@openssl.org \
578 -to someone@somewhere -subject "Encrypted message" \
579 -des3 user.pem -out mail.msg
581 Sign and encrypt mail:
583 openssl cms -sign -in ml.txt -signer my.pem -text \
584 | openssl cms -encrypt -out mail.msg \
585 -from steve@openssl.org -to someone@somewhere \
586 -subject "Signed and Encrypted message" -des3 user.pem
588 Note: the encryption command does not include the B<-text> option because the
589 message being encrypted already has MIME headers.
593 openssl cms -decrypt -in mail.msg -recip mycert.pem -inkey key.pem
595 The output from Netscape form signing is a PKCS#7 structure with the
596 detached signature format. You can use this program to verify the
597 signature by line wrapping the base64 encoded structure and surrounding
600 -----BEGIN PKCS7-----
603 and using the command,
605 openssl cms -verify -inform PEM -in signature.pem -content content.txt
607 alternatively you can base64 decode the signature and use
609 openssl cms -verify -inform DER -in signature.der -content content.txt
611 Create an encrypted message using 128 bit Camellia:
613 openssl cms -encrypt -in plain.txt -camellia128 -out mail.msg cert.pem
615 Add a signer to an existing message:
617 openssl cms -resign -in mail.msg -signer newsign.pem -out mail2.msg
619 Sign mail using RSA-PSS:
621 openssl cms -sign -in message.txt -text -out mail.msg \
622 -signer mycert.pem -keyopt rsa_padding_mode:pss
624 Create encrypted mail using RSA-OAEP:
626 openssl cms -encrypt -in plain.txt -out mail.msg \
627 -recip cert.pem -keyopt rsa_padding_mode:oaep
629 Use SHA256 KDF with an ECDH certificate:
631 openssl cms -encrypt -in plain.txt -out mail.msg \
632 -recip ecdhcert.pem -keyopt ecdh_kdf_md:sha256
636 The MIME parser isn't very clever: it seems to handle most messages that I've
637 thrown at it but it may choke on others.
639 The code currently will only write out the signer's certificate to a file: if
640 the signer has a separate encryption certificate this must be manually
641 extracted. There should be some heuristic that determines the correct
642 encryption certificate.
644 Ideally a database should be maintained of a certificates for each email
647 The code doesn't currently take note of the permitted symmetric encryption
648 algorithms as supplied in the SMIMECapabilities signed attribute. this means the
649 user has to manually include the correct encryption algorithm. It should store
650 the list of permitted ciphers in a database and only use those.
652 No revocation checking is done on the signer's certificate.
656 The use of multiple B<-signer> options and the B<-resign> command were first
657 added in OpenSSL 1.0.0
659 The B<keyopt> option was first added in OpenSSL 1.1.0
661 The use of B<-recip> to specify the recipient when encrypting mail was first
662 added to OpenSSL 1.1.0
664 Support for RSA-OAEP and RSA-PSS was first added to OpenSSL 1.1.0.
666 The use of non-RSA keys with B<-encrypt> and B<-decrypt> was first added