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>]
43 [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>.
90 Note that no revocation check is done for the recipient cert, so if that
91 key has been compromised, others may be able to decrypt the text.
95 decrypt mail using the supplied certificate and private key. Expects an
96 encrypted mail message in MIME format for the input file. The decrypted mail
97 is written to the output file.
99 =item B<-debug_decrypt>
101 this option sets the B<CMS_DEBUG_DECRYPT> flag. This option should be used
102 with caution: see the notes section below.
106 sign mail using the supplied certificate and private key. Input file is
107 the message to be signed. The signed message in MIME format is written
112 verify signed mail. Expects a signed mail message on input and outputs
113 the signed data. Both clear text and opaque signing is supported.
117 takes an input message and writes out a PEM encoded CMS structure.
121 resign a message: take an existing message and one or more new signers.
123 =item B<-data_create>
125 Create a CMS B<Data> type.
129 B<Data> type and output the content.
131 =item B<-digest_create>
133 Create a CMS B<DigestedData> type.
135 =item B<-digest_verify>
137 Verify a CMS B<DigestedData> type and output the content.
141 Create a CMS B<CompressedData> type. OpenSSL must be compiled with B<zlib>
142 support for this option to work, otherwise it will output an error.
146 Uncompress a CMS B<CompressedData> type and output the content. OpenSSL must be
147 compiled with B<zlib> support for this option to work, otherwise it will
150 =item B<-EncryptedData_encrypt>
152 Encrypt content using supplied symmetric key and algorithm using a CMS
153 B<EncrytedData> type and output the content.
155 =item B<-sign_receipt>
157 Generate and output a signed receipt for the supplied message. The input
158 message B<must> contain a signed receipt request. Functionality is otherwise
159 similar to the B<-sign> operation.
161 =item B<-verify_receipt receipt>
163 Verify a signed receipt in filename B<receipt>. The input message B<must>
164 contain the original receipt request. Functionality is otherwise similar
165 to the B<-verify> operation.
167 =item B<-in filename>
169 the input message to be encrypted or signed or the message to be decrypted
172 =item B<-inform SMIME|PEM|DER>
174 this specifies the input format for the CMS structure. The default
175 is B<SMIME> which reads an S/MIME format message. B<PEM> and B<DER>
176 format change this to expect PEM and DER format CMS structures
177 instead. This currently only affects the input format of the CMS
178 structure, if no CMS structure is being input (for example with
179 B<-encrypt> or B<-sign>) this option has no effect.
181 =item B<-rctform SMIME|PEM|DER>
183 specify the format for a signed receipt for use with the B<-receipt_verify>
186 =item B<-out filename>
188 the message text that has been decrypted or verified or the output MIME
189 format message that has been signed or verified.
191 =item B<-outform SMIME|PEM|DER>
193 this specifies the output format for the CMS structure. The default
194 is B<SMIME> which writes an S/MIME format message. B<PEM> and B<DER>
195 format change this to write PEM and DER format CMS structures
196 instead. This currently only affects the output format of the CMS
197 structure, if no CMS structure is being output (for example with
198 B<-verify> or B<-decrypt>) this option has no effect.
200 =item B<-stream -indef -noindef>
202 the B<-stream> and B<-indef> options are equivalent and enable streaming I/O
203 for encoding operations. This permits single pass processing of data without
204 the need to hold the entire contents in memory, potentially supporting very
205 large files. Streaming is automatically set for S/MIME signing with detached
206 data if the output format is B<SMIME> it is currently off by default for all
211 disable streaming I/O where it would produce and indefinite length constructed
212 encoding. This option currently has no effect. In future streaming will be
213 enabled by default on all relevant operations and this option will disable it.
215 =item B<-content filename>
217 This specifies a file containing the detached content, this is only
218 useful with the B<-verify> command. This is only usable if the CMS
219 structure is using the detached signature form where the content is
220 not included. This option will override any content if the input format
221 is S/MIME and it uses the multipart/signed MIME content type.
225 this option adds plain text (text/plain) MIME headers to the supplied
226 message if encrypting or signing. If decrypting or verifying it strips
227 off text headers: if the decrypted or verified message is not of MIME
228 type text/plain then an error occurs.
232 for the B<-cmsout> operation do not output the parsed CMS structure. This
233 is useful when combined with the B<-print> option or if the syntax of the CMS
234 structure is being checked.
238 for the B<-cmsout> operation print out all fields of the CMS structure. This
239 is mainly useful for testing purposes.
241 =item B<-CAfile file>
243 a file containing trusted CA certificates, only used with B<-verify>.
247 a directory containing trusted CA certificates, only used with
248 B<-verify>. This directory must be a standard certificate directory: that
249 is a hash of each subject name (using B<x509 -hash>) should be linked
254 digest algorithm to use when signing or resigning. If not present then the
255 default digest algorithm for the signing key will be used (usually SHA1).
259 the encryption algorithm to use. For example triple DES (168 bits) - B<-des3>
260 or 256 bit AES - B<-aes256>. Any standard algorithm name (as used by the
261 EVP_get_cipherbyname() function) can also be used preceded by a dash, for
262 example B<-aes_128_cbc>. See L<B<enc>|enc(1)> for a list of ciphers
263 supported by your version of OpenSSL.
265 If not specified triple DES is used. Only used with B<-encrypt> and
266 B<-EncryptedData_create> commands.
270 when verifying a message normally certificates (if any) included in
271 the message are searched for the signing certificate. With this option
272 only the certificates specified in the B<-certfile> option are used.
273 The supplied certificates can still be used as untrusted CAs however.
275 =item B<-no_signer_cert_verify>
277 do not verify the signers certificate of a signed message.
281 when signing a message the signer's certificate is normally included
282 with this option it is excluded. This will reduce the size of the
283 signed message but the verifier must have a copy of the signers certificate
284 available locally (passed using the B<-certfile> option for example).
288 normally when a message is signed a set of attributes are included which
289 include the signing time and supported symmetric algorithms. With this
290 option they are not included.
294 exclude the list of supported algorithms from signed attributes, other options
295 such as signing time and content type are still included.
299 normally the input message is converted to "canonical" format which is
300 effectively using CR and LF as end of line: as required by the S/MIME
301 specification. When this option is present no translation occurs. This
302 is useful when handling binary data which may not be in MIME format.
306 when signing a message use opaque signing: this form is more resistant
307 to translation by mail relays but it cannot be read by mail agents that
308 do not support S/MIME. Without this option cleartext signing with
309 the MIME type multipart/signed is used.
311 =item B<-certfile file>
313 allows additional certificates to be specified. When signing these will
314 be included with the message. When verifying these will be searched for
315 the signers certificates. The certificates should be in PEM format.
317 =item B<-certsout file>
319 any certificates contained in the message are written to B<file>.
321 =item B<-signer file>
323 a signing certificate when signing or resigning a message, this option can be
324 used multiple times if more than one signer is required. If a message is being
325 verified then the signers certificates will be written to this file if the
326 verification was successful.
330 when decrypting a message this specifies the recipients certificate. The
331 certificate must match one of the recipients of the message or an error
334 When encrypting a message this option may be used multiple times to specify
335 each recipient. This form B<must> be used if customised parameters are
336 required (for example to specify RSA-OAEP).
340 use subject key identifier to identify certificates instead of issuer name and
341 serial number. The supplied certificate B<must> include a subject key
342 identifier extension. Supported by B<-sign> and B<-encrypt> options.
344 =item B<-receipt_request_all -receipt_request_first>
346 for B<-sign> option include a signed receipt request. Indicate requests should
347 be provided by all receipient or first tier recipients (those mailed directly
348 and not from a mailing list). Ignored it B<-receipt_request_from> is included.
350 =item B<-receipt_request_from emailaddress>
352 for B<-sign> option include a signed receipt request. Add an explicit email
353 address where receipts should be supplied.
355 =item B<-receipt_request_to emailaddress>
357 Add an explicit email address where signed receipts should be sent to. This
358 option B<must> but supplied if a signed receipt it requested.
360 =item B<-receipt_request_print>
362 For the B<-verify> operation print out the contents of any signed receipt
365 =item B<-secretkey key>
367 specify symmetric key to use. The key must be supplied in hex format and be
368 consistent with the algorithm used. Supported by the B<-EncryptedData_encrypt>
369 B<-EncrryptedData_decrypt>, B<-encrypt> and B<-decrypt> options. When used
370 with B<-encrypt> or B<-decrypt> the supplied key is used to wrap or unwrap the
371 content encryption key using an AES key in the B<KEKRecipientInfo> type.
373 =item B<-secretkeyid id>
375 the key identifier for the supplied symmetric key for B<KEKRecipientInfo> type.
376 This option B<must> be present if the B<-secretkey> option is used with
377 B<-encrypt>. With B<-decrypt> operations the B<id> is used to locate the
378 relevant key if it is not supplied then an attempt is used to decrypt any
379 B<KEKRecipientInfo> structures.
381 =item B<-econtent_type type>
383 set the encapsulated content type to B<type> if not supplied the B<Data> type
384 is used. The B<type> argument can be any valid OID name in either text or
389 the private key to use when signing or decrypting. This must match the
390 corresponding certificate. If this option is not specified then the
391 private key must be included in the certificate file specified with
392 the B<-recip> or B<-signer> file. When signing this option can be used
393 multiple times to specify successive keys.
395 =item B<-keyopt name:opt>
397 for signing and encryption this option can be used multiple times to
398 set customised parameters for the preceding key or certificate. It can
399 currently be used to set RSA-PSS for signing, RSA-OAEP for encryption
400 or to modify default parameters for ECDH.
404 the private key password source. For more information about the format of B<arg>
405 see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)|openssl(1)>.
407 =item B<-rand file(s)>
409 a file or files containing random data used to seed the random number
410 generator, or an EGD socket (see L<RAND_egd(3)|RAND_egd(3)>).
411 Multiple files can be specified separated by a OS-dependent character.
412 The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for
417 one or more certificates of message recipients: used when encrypting
420 =item B<-to, -from, -subject>
422 the relevant mail headers. These are included outside the signed
423 portion of a message so they may be included manually. If signing
424 then many S/MIME mail clients check the signers certificate's email
425 address matches that specified in the From: address.
427 =item B<-purpose, -ignore_critical, -issuer_checks, -crl_check, -crl_check_all, -policy_check, -extended_crl, -x509_strict, -policy -check_ss_sig -no_alt_chains>
429 Set various certificate chain valiadition option. See the
430 L<B<verify>|verify(1)> manual page for details.
436 The MIME message must be sent without any blank lines between the
437 headers and the output. Some mail programs will automatically add
438 a blank line. Piping the mail directly to sendmail is one way to
439 achieve the correct format.
441 The supplied message to be signed or encrypted must include the
442 necessary MIME headers or many S/MIME clients wont display it
443 properly (if at all). You can use the B<-text> option to automatically
444 add plain text headers.
446 A "signed and encrypted" message is one where a signed message is
447 then encrypted. This can be produced by encrypting an already signed
448 message: see the examples section.
450 This version of the program only allows one signer per message but it
451 will verify multiple signers on received messages. Some S/MIME clients
452 choke if a message contains multiple signers. It is possible to sign
453 messages "in parallel" by signing an already signed message.
455 The options B<-encrypt> and B<-decrypt> reflect common usage in S/MIME
456 clients. Strictly speaking these process CMS enveloped data: CMS
457 encrypted data is used for other purposes.
459 The B<-resign> option uses an existing message digest when adding a new
460 signer. This means that attributes must be present in at least one existing
461 signer using the same message digest or this operation will fail.
463 The B<-stream> and B<-indef> options enable experimental streaming I/O support.
464 As a result the encoding is BER using indefinite length constructed encoding
465 and no longer DER. Streaming is supported for the B<-encrypt> operation and the
466 B<-sign> operation if the content is not detached.
468 Streaming is always used for the B<-sign> operation with detached data but
469 since the content is no longer part of the CMS structure the encoding
472 If the B<-decrypt> option is used without a recipient certificate then an
473 attempt is made to locate the recipient by trying each potential recipient
474 in turn using the supplied private key. To thwart the MMA attack
475 (Bleichenbacher's attack on PKCS #1 v1.5 RSA padding) all recipients are
476 tried whether they succeed or not and if no recipients match the message
477 is "decrypted" using a random key which will typically output garbage.
478 The B<-debug_decrypt> option can be used to disable the MMA attack protection
479 and return an error if no recipient can be found: this option should be used
480 with caution. For a fuller description see L<CMS_decrypt(3)|CMS_decrypt(3)>).
488 the operation was completely successfully.
492 an error occurred parsing the command options.
496 one of the input files could not be read.
500 an error occurred creating the CMS file or when reading the MIME
505 an error occurred decrypting or verifying the message.
509 the message was verified correctly but an error occurred writing out
510 the signers certificates.
514 =head1 COMPATIBILITY WITH PKCS#7 format.
516 The B<smime> utility can only process the older B<PKCS#7> format. The B<cms>
517 utility supports Cryptographic Message Syntax format. Use of some features
518 will result in messages which cannot be processed by applications which only
519 support the older format. These are detailed below.
521 The use of the B<-keyid> option with B<-sign> or B<-encrypt>.
523 The B<-outform PEM> option uses different headers.
525 The B<-compress> option.
527 The B<-secretkey> option when used with B<-encrypt>.
529 The use of PSS with B<-sign>.
531 The use of OAEP or non-RSA keys with B<-encrypt>.
533 Additionally the B<-EncryptedData_create> and B<-data_create> type cannot
534 be processed by the older B<smime> command.
538 Create a cleartext signed message:
540 openssl cms -sign -in message.txt -text -out mail.msg \
543 Create an opaque signed message
545 openssl cms -sign -in message.txt -text -out mail.msg -nodetach \
548 Create a signed message, include some additional certificates and
549 read the private key from another file:
551 openssl cms -sign -in in.txt -text -out mail.msg \
552 -signer mycert.pem -inkey mykey.pem -certfile mycerts.pem
554 Create a signed message with two signers, use key identifier:
556 openssl cms -sign -in message.txt -text -out mail.msg \
557 -signer mycert.pem -signer othercert.pem -keyid
559 Send a signed message under Unix directly to sendmail, including headers:
561 openssl cms -sign -in in.txt -text -signer mycert.pem \
562 -from steve@openssl.org -to someone@somewhere \
563 -subject "Signed message" | sendmail someone@somewhere
565 Verify a message and extract the signer's certificate if successful:
567 openssl cms -verify -in mail.msg -signer user.pem -out signedtext.txt
569 Send encrypted mail using triple DES:
571 openssl cms -encrypt -in in.txt -from steve@openssl.org \
572 -to someone@somewhere -subject "Encrypted message" \
573 -des3 user.pem -out mail.msg
575 Sign and encrypt mail:
577 openssl cms -sign -in ml.txt -signer my.pem -text \
578 | openssl cms -encrypt -out mail.msg \
579 -from steve@openssl.org -to someone@somewhere \
580 -subject "Signed and Encrypted message" -des3 user.pem
582 Note: the encryption command does not include the B<-text> option because the
583 message being encrypted already has MIME headers.
587 openssl cms -decrypt -in mail.msg -recip mycert.pem -inkey key.pem
589 The output from Netscape form signing is a PKCS#7 structure with the
590 detached signature format. You can use this program to verify the
591 signature by line wrapping the base64 encoded structure and surrounding
594 -----BEGIN PKCS7-----
597 and using the command,
599 openssl cms -verify -inform PEM -in signature.pem -content content.txt
601 alternatively you can base64 decode the signature and use
603 openssl cms -verify -inform DER -in signature.der -content content.txt
605 Create an encrypted message using 128 bit Camellia:
607 openssl cms -encrypt -in plain.txt -camellia128 -out mail.msg cert.pem
609 Add a signer to an existing message:
611 openssl cms -resign -in mail.msg -signer newsign.pem -out mail2.msg
613 Sign mail using RSA-PSS:
615 openssl cms -sign -in message.txt -text -out mail.msg \
616 -signer mycert.pem -keyopt rsa_padding_mode:pss
618 Create encrypted mail using RSA-OAEP:
620 openssl cms -encrypt -in plain.txt -out mail.msg \
621 -recip cert.pem -keyopt rsa_padding_mode:oaep
623 Use SHA256 KDF with an ECDH certificate:
625 openssl cms -encrypt -in plain.txt -out mail.msg \
626 -recip ecdhcert.pem -keyopt ecdh_kdf_md:sha256
630 The MIME parser isn't very clever: it seems to handle most messages that I've
631 thrown at it but it may choke on others.
633 The code currently will only write out the signer's certificate to a file: if
634 the signer has a separate encryption certificate this must be manually
635 extracted. There should be some heuristic that determines the correct
636 encryption certificate.
638 Ideally a database should be maintained of a certificates for each email
641 The code doesn't currently take note of the permitted symmetric encryption
642 algorithms as supplied in the SMIMECapabilities signed attribute. this means the
643 user has to manually include the correct encryption algorithm. It should store
644 the list of permitted ciphers in a database and only use those.
646 No revocation checking is done on the signer's certificate.
650 The use of multiple B<-signer> options and the B<-resign> command were first
651 added in OpenSSL 1.0.0
653 The B<keyopt> option was first added in OpenSSL 1.1.0
655 The use of B<-recip> to specify the recipient when encrypting mail was first
656 added to OpenSSL 1.1.0
658 Support for RSA-OAEP and RSA-PSS was first added to OpenSSL 1.1.0.
660 The use of non-RSA keys with B<-encrypt> and B<-decrypt> was first added
663 The -no_alt_chains options was first added to OpenSSL 1.0.2b.