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>]
41 [B<-no_signer_cert_verify>]
53 [B<-receipt_request_all -receipt_request_first>]
54 [B<-receipt_request_from emailaddress>]
55 [B<-receipt_request_to emailaddress>]
56 [B<-receipt_request_print>]
59 [B<-econtent_type type>]
61 [B<-keyopt name:parameter>]
72 The B<cms> command handles S/MIME v3.1 mail. It can encrypt, decrypt, sign and
73 verify, compress and uncompress S/MIME messages.
75 =head1 COMMAND OPTIONS
77 There are fourteen operation options that set the type of operation to be
78 performed. The meaning of the other options varies according to the operation
85 encrypt mail for the given recipient certificates. Input file is the message
86 to be encrypted. The output file is the encrypted mail in MIME format. The
87 actual CMS type is <B>EnvelopedData<B>.
91 decrypt mail using the supplied certificate and private key. Expects an
92 encrypted mail message in MIME format for the input file. The decrypted mail
93 is written to the output file.
95 =item B<-debug_decrypt>
97 this option sets the B<CMS_DEBUG_DECRYPT> flag. This option should be used
98 with caution: see the notes section below.
102 sign mail using the supplied certificate and private key. Input file is
103 the message to be signed. The signed message in MIME format is written
108 verify signed mail. Expects a signed mail message on input and outputs
109 the signed data. Both clear text and opaque signing is supported.
113 takes an input message and writes out a PEM encoded CMS structure.
117 resign a message: take an existing message and one or more new signers.
119 =item B<-data_create>
121 Create a CMS B<Data> type.
125 B<Data> type and output the content.
127 =item B<-digest_create>
129 Create a CMS B<DigestedData> type.
131 =item B<-digest_verify>
133 Verify a CMS B<DigestedData> type and output the content.
137 Create a CMS B<CompressedData> type. OpenSSL must be compiled with B<zlib>
138 support for this option to work, otherwise it will output an error.
142 Uncompress a CMS B<CompressedData> type and output the content. OpenSSL must be
143 compiled with B<zlib> support for this option to work, otherwise it will
146 =item B<-EncryptedData_encrypt>
148 Encrypt suppled content using supplied symmetric key and algorithm using a CMS
149 B<EncrytedData> type and output the content.
151 =item B<-sign_receipt>
153 Generate and output a signed receipt for the supplied message. The input
154 message B<must> contain a signed receipt request. Functionality is otherwise
155 similar to the B<-sign> operation.
157 =item B<-verify_receipt receipt>
159 Verify a signed receipt in filename B<receipt>. The input message B<must>
160 contain the original receipt request. Functionality is otherwise similar
161 to the B<-verify> operation.
163 =item B<-in filename>
165 the input message to be encrypted or signed or the message to be decrypted
168 =item B<-inform SMIME|PEM|DER>
170 this specifies the input format for the CMS structure. The default
171 is B<SMIME> which reads an S/MIME format message. B<PEM> and B<DER>
172 format change this to expect PEM and DER format CMS structures
173 instead. This currently only affects the input format of the CMS
174 structure, if no CMS structure is being input (for example with
175 B<-encrypt> or B<-sign>) this option has no effect.
177 =item B<-rctform SMIME|PEM|DER>
179 specify the format for a signed receipt for use with the B<-receipt_verify>
182 =item B<-out filename>
184 the message text that has been decrypted or verified or the output MIME
185 format message that has been signed or verified.
187 =item B<-outform SMIME|PEM|DER>
189 this specifies the output format for the CMS structure. The default
190 is B<SMIME> which writes an S/MIME format message. B<PEM> and B<DER>
191 format change this to write PEM and DER format CMS structures
192 instead. This currently only affects the output format of the CMS
193 structure, if no CMS structure is being output (for example with
194 B<-verify> or B<-decrypt>) this option has no effect.
196 =item B<-stream -indef -noindef>
198 the B<-stream> and B<-indef> options are equivalent and enable streaming I/O
199 for encoding operations. This permits single pass processing of data without
200 the need to hold the entire contents in memory, potentially supporting very
201 large files. Streaming is automatically set for S/MIME signing with detached
202 data if the output format is B<SMIME> it is currently off by default for all
207 disable streaming I/O where it would produce and indefinite length constructed
208 encoding. This option currently has no effect. In future streaming will be
209 enabled by default on all relevant operations and this option will disable it.
211 =item B<-content filename>
213 This specifies a file containing the detached content, this is only
214 useful with the B<-verify> command. This is only usable if the CMS
215 structure is using the detached signature form where the content is
216 not included. This option will override any content if the input format
217 is S/MIME and it uses the multipart/signed MIME content type.
221 this option adds plain text (text/plain) MIME headers to the supplied
222 message if encrypting or signing. If decrypting or verifying it strips
223 off text headers: if the decrypted or verified message is not of MIME
224 type text/plain then an error occurs.
228 for the B<-cmsout> operation do not output the parsed CMS structure. This
229 is useful when combined with the B<-print> option or if the syntax of the CMS
230 structure is being checked.
234 for the B<-cmsout> operation print out all fields of the CMS structure. This
235 is mainly useful for testing purposes.
237 =item B<-CAfile file>
239 a file containing trusted CA certificates, only used with B<-verify>.
243 a directory containing trusted CA certificates, only used with
244 B<-verify>. This directory must be a standard certificate directory: that
245 is a hash of each subject name (using B<x509 -hash>) should be linked
250 digest algorithm to use when signing or resigning. If not present then the
251 default digest algorithm for the signing key will be used (usually SHA1).
255 the encryption algorithm to use. For example triple DES (168 bits) - B<-des3>
256 or 256 bit AES - B<-aes256>. Any standard algorithm name (as used by the
257 EVP_get_cipherbyname() function) can also be used preceded by a dash, for
258 example B<-aes_128_cbc>. See L<B<enc>|enc(1)> for a list of ciphers
259 supported by your version of OpenSSL.
261 If not specified triple DES is used. Only used with B<-encrypt> and
262 B<-EncryptedData_create> commands.
266 when verifying a message normally certificates (if any) included in
267 the message are searched for the signing certificate. With this option
268 only the certificates specified in the B<-certfile> option are used.
269 The supplied certificates can still be used as untrusted CAs however.
271 =item B<-no_signer_cert_verify>
273 do not verify the signers certificate of a signed message.
277 when signing a message the signer's certificate is normally included
278 with this option it is excluded. This will reduce the size of the
279 signed message but the verifier must have a copy of the signers certificate
280 available locally (passed using the B<-certfile> option for example).
284 normally when a message is signed a set of attributes are included which
285 include the signing time and supported symmetric algorithms. With this
286 option they are not included.
290 exclude the list of supported algorithms from signed attributes, other options
291 such as signing time and content type are still included.
295 normally the input message is converted to "canonical" format which is
296 effectively using CR and LF as end of line: as required by the S/MIME
297 specification. When this option is present no translation occurs. This
298 is useful when handling binary data which may not be in MIME format.
302 when signing use ASCII CRLF format canonicalisation. This strips trailing
303 whitespace from all lines, deletes trailing blank lines at EOF and sets
304 the encapsulated content type. This option is normally used with detached
305 content and an output signature format of DER. This option is not normally
306 needed when verifying as it is enabled automatically if the encapsulated
307 content format is detected.
311 when signing a message use opaque signing: this form is more resistant
312 to translation by mail relays but it cannot be read by mail agents that
313 do not support S/MIME. Without this option cleartext signing with
314 the MIME type multipart/signed is used.
316 =item B<-certfile file>
318 allows additional certificates to be specified. When signing these will
319 be included with the message. When verifying these will be searched for
320 the signers certificates. The certificates should be in PEM format.
322 =item B<-certsout file>
324 any certificates contained in the message are written to B<file>.
326 =item B<-signer file>
328 a signing certificate when signing or resigning a message, this option can be
329 used multiple times if more than one signer is required. If a message is being
330 verified then the signers certificates will be written to this file if the
331 verification was successful.
335 when decrypting a message this specifies the recipients certificate. The
336 certificate must match one of the recipients of the message or an error
339 When encrypting a message this option may be used multiple times to specify
340 each recipient. This form B<must> be used if customised parameters are
341 required (for example to specify RSA-OAEP).
345 use subject key identifier to identify certificates instead of issuer name and
346 serial number. The supplied certificate B<must> include a subject key
347 identifier extension. Supported by B<-sign> and B<-encrypt> options.
349 =item B<-receipt_request_all -receipt_request_first>
351 for B<-sign> option include a signed receipt request. Indicate requests should
352 be provided by all receipient or first tier recipients (those mailed directly
353 and not from a mailing list). Ignored it B<-receipt_request_from> is included.
355 =item B<-receipt_request_from emailaddress>
357 for B<-sign> option include a signed receipt request. Add an explicit email
358 address where receipts should be supplied.
360 =item B<-receipt_request_to emailaddress>
362 Add an explicit email address where signed receipts should be sent to. This
363 option B<must> but supplied if a signed receipt it requested.
365 =item B<-receipt_request_print>
367 For the B<-verify> operation print out the contents of any signed receipt
370 =item B<-secretkey key>
372 specify symmetric key to use. The key must be supplied in hex format and be
373 consistent with the algorithm used. Supported by the B<-EncryptedData_encrypt>
374 B<-EncrryptedData_decrypt>, B<-encrypt> and B<-decrypt> options. When used
375 with B<-encrypt> or B<-decrypt> the supplied key is used to wrap or unwrap the
376 content encryption key using an AES key in the B<KEKRecipientInfo> type.
378 =item B<-secretkeyid id>
380 the key identifier for the supplied symmetric key for B<KEKRecipientInfo> type.
381 This option B<must> be present if the B<-secretkey> option is used with
382 B<-encrypt>. With B<-decrypt> operations the B<id> is used to locate the
383 relevant key if it is not supplied then an attempt is used to decrypt any
384 B<KEKRecipientInfo> structures.
386 =item B<-econtent_type type>
388 set the encapsulated content type to B<type> if not supplied the B<Data> type
389 is used. The B<type> argument can be any valid OID name in either text or
394 the private key to use when signing or decrypting. This must match the
395 corresponding certificate. If this option is not specified then the
396 private key must be included in the certificate file specified with
397 the B<-recip> or B<-signer> file. When signing this option can be used
398 multiple times to specify successive keys.
400 =item B<-keyopt name:opt>
402 for signing and encryption this option can be used multiple times to
403 set customised parameters for the preceding key or certificate. It can
404 currently be used to set RSA-PSS for signing, RSA-OAEP for encryption
405 or to modify default parameters for ECDH.
409 the private key password source. For more information about the format of B<arg>
410 see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)|openssl(1)>.
412 =item B<-rand file(s)>
414 a file or files containing random data used to seed the random number
415 generator, or an EGD socket (see L<RAND_egd(3)|RAND_egd(3)>).
416 Multiple files can be specified separated by a OS-dependent character.
417 The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for
422 one or more certificates of message recipients: used when encrypting
425 =item B<-to, -from, -subject>
427 the relevant mail headers. These are included outside the signed
428 portion of a message so they may be included manually. If signing
429 then many S/MIME mail clients check the signers certificate's email
430 address matches that specified in the From: address.
432 =item B<-purpose, -ignore_critical, -issuer_checks, -crl_check, -crl_check_all, -policy_check, -extended_crl, -x509_strict, -policy -check_ss_sig>
434 Set various certificate chain valiadition option. See the
435 L<B<verify>|verify(1)> manual page for details.
441 The MIME message must be sent without any blank lines between the
442 headers and the output. Some mail programs will automatically add
443 a blank line. Piping the mail directly to sendmail is one way to
444 achieve the correct format.
446 The supplied message to be signed or encrypted must include the
447 necessary MIME headers or many S/MIME clients wont display it
448 properly (if at all). You can use the B<-text> option to automatically
449 add plain text headers.
451 A "signed and encrypted" message is one where a signed message is
452 then encrypted. This can be produced by encrypting an already signed
453 message: see the examples section.
455 This version of the program only allows one signer per message but it
456 will verify multiple signers on received messages. Some S/MIME clients
457 choke if a message contains multiple signers. It is possible to sign
458 messages "in parallel" by signing an already signed message.
460 The options B<-encrypt> and B<-decrypt> reflect common usage in S/MIME
461 clients. Strictly speaking these process CMS enveloped data: CMS
462 encrypted data is used for other purposes.
464 The B<-resign> option uses an existing message digest when adding a new
465 signer. This means that attributes must be present in at least one existing
466 signer using the same message digest or this operation will fail.
468 The B<-stream> and B<-indef> options enable experimental streaming I/O support.
469 As a result the encoding is BER using indefinite length constructed encoding
470 and no longer DER. Streaming is supported for the B<-encrypt> operation and the
471 B<-sign> operation if the content is not detached.
473 Streaming is always used for the B<-sign> operation with detached data but
474 since the content is no longer part of the CMS structure the encoding
477 If the B<-decrypt> option is used without a recipient certificate then an
478 attempt is made to locate the recipient by trying each potential recipient
479 in turn using the supplied private key. To thwart the MMA attack
480 (Bleichenbacher's attack on PKCS #1 v1.5 RSA padding) all recipients are
481 tried whether they succeed or not and if no recipients match the message
482 is "decrypted" using a random key which will typically output garbage.
483 The B<-debug_decrypt> option can be used to disable the MMA attack protection
484 and return an error if no recipient can be found: this option should be used
485 with caution. For a fuller description see L<CMS_decrypt(3)|CMS_decrypt(3)>).
493 the operation was completely successfully.
497 an error occurred parsing the command options.
501 one of the input files could not be read.
505 an error occurred creating the CMS file or when reading the MIME
510 an error occurred decrypting or verifying the message.
514 the message was verified correctly but an error occurred writing out
515 the signers certificates.
519 =head1 COMPATIBILITY WITH PKCS#7 format.
521 The B<smime> utility can only process the older B<PKCS#7> format. The B<cms>
522 utility supports Cryptographic Message Syntax format. Use of some features
523 will result in messages which cannot be processed by applications which only
524 support the older format. These are detailed below.
526 The use of the B<-keyid> option with B<-sign> or B<-encrypt>.
528 The B<-outform PEM> option uses different headers.
530 The B<-compress> option.
532 The B<-secretkey> option when used with B<-encrypt>.
534 The use of PSS with B<-sign>.
536 The use of OAEP or non-RSA keys with B<-encrypt>.
538 Additionally the B<-EncryptedData_create> and B<-data_create> type cannot
539 be processed by the older B<smime> command.
543 Create a cleartext signed message:
545 openssl cms -sign -in message.txt -text -out mail.msg \
548 Create an opaque signed message
550 openssl cms -sign -in message.txt -text -out mail.msg -nodetach \
553 Create a signed message, include some additional certificates and
554 read the private key from another file:
556 openssl cms -sign -in in.txt -text -out mail.msg \
557 -signer mycert.pem -inkey mykey.pem -certfile mycerts.pem
559 Create a signed message with two signers, use key identifier:
561 openssl cms -sign -in message.txt -text -out mail.msg \
562 -signer mycert.pem -signer othercert.pem -keyid
564 Send a signed message under Unix directly to sendmail, including headers:
566 openssl cms -sign -in in.txt -text -signer mycert.pem \
567 -from steve@openssl.org -to someone@somewhere \
568 -subject "Signed message" | sendmail someone@somewhere
570 Verify a message and extract the signer's certificate if successful:
572 openssl cms -verify -in mail.msg -signer user.pem -out signedtext.txt
574 Send encrypted mail using triple DES:
576 openssl cms -encrypt -in in.txt -from steve@openssl.org \
577 -to someone@somewhere -subject "Encrypted message" \
578 -des3 user.pem -out mail.msg
580 Sign and encrypt mail:
582 openssl cms -sign -in ml.txt -signer my.pem -text \
583 | openssl cms -encrypt -out mail.msg \
584 -from steve@openssl.org -to someone@somewhere \
585 -subject "Signed and Encrypted message" -des3 user.pem
587 Note: the encryption command does not include the B<-text> option because the
588 message being encrypted already has MIME headers.
592 openssl cms -decrypt -in mail.msg -recip mycert.pem -inkey key.pem
594 The output from Netscape form signing is a PKCS#7 structure with the
595 detached signature format. You can use this program to verify the
596 signature by line wrapping the base64 encoded structure and surrounding
599 -----BEGIN PKCS7-----
602 and using the command,
604 openssl cms -verify -inform PEM -in signature.pem -content content.txt
606 alternatively you can base64 decode the signature and use
608 openssl cms -verify -inform DER -in signature.der -content content.txt
610 Create an encrypted message using 128 bit Camellia:
612 openssl cms -encrypt -in plain.txt -camellia128 -out mail.msg cert.pem
614 Add a signer to an existing message:
616 openssl cms -resign -in mail.msg -signer newsign.pem -out mail2.msg
618 Sign mail using RSA-PSS:
620 openssl cms -sign -in message.txt -text -out mail.msg \
621 -signer mycert.pem -keyopt rsa_padding_mode:pss
623 Create encrypted mail using RSA-OAEP:
625 openssl cms -encrypt -in plain.txt -out mail.msg \
626 -recip cert.pem -keyopt rsa_padding_mode:oaep
628 Use SHA256 KDF with an ECDH certificate:
630 openssl cms -encrypt -in plain.txt -out mail.msg \
631 -recip ecdhcert.pem -keyopt ecdh_kdf_md:sha256
635 The MIME parser isn't very clever: it seems to handle most messages that I've
636 thrown at it but it may choke on others.
638 The code currently will only write out the signer's certificate to a file: if
639 the signer has a separate encryption certificate this must be manually
640 extracted. There should be some heuristic that determines the correct
641 encryption certificate.
643 Ideally a database should be maintained of a certificates for each email
646 The code doesn't currently take note of the permitted symmetric encryption
647 algorithms as supplied in the SMIMECapabilities signed attribute. this means the
648 user has to manually include the correct encryption algorithm. It should store
649 the list of permitted ciphers in a database and only use those.
651 No revocation checking is done on the signer's certificate.
655 The use of multiple B<-signer> options and the B<-resign> command were first
656 added in OpenSSL 1.0.0
658 The B<keyopt> option was first added in OpenSSL 1.1.0
660 The use of B<-recip> to specify the recipient when encrypting mail was first
661 added to OpenSSL 1.1.0
663 Support for RSA-OAEP and RSA-PSS was first added to OpenSSL 1.1.0.
665 The use of non-RSA keys with B<-encrypt> and B<-decrypt> was first added