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>]
52 [B<-receipt_request_all -receipt_request_first>]
53 [B<-receipt_request_from emailaddress>]
54 [B<-receipt_request_to emailaddress>]
55 [B<-receipt_request_print>]
58 [B<-econtent_type type>]
60 [B<-keyopt name:parameter>]
71 The B<cms> command handles S/MIME v3.1 mail. It can encrypt, decrypt, sign and
72 verify, compress and uncompress S/MIME messages.
74 =head1 COMMAND OPTIONS
76 There are fourteen operation options that set the type of operation to be
77 performed. The meaning of the other options varies according to the operation
84 encrypt mail for the given recipient certificates. Input file is the message
85 to be encrypted. The output file is the encrypted mail in MIME format. The
86 actual CMS type is <B>EnvelopedData<B>.
90 decrypt mail using the supplied certificate and private key. Expects an
91 encrypted mail message in MIME format for the input file. The decrypted mail
92 is written to the output file.
96 sign mail using the supplied certificate and private key. Input file is
97 the message to be signed. The signed message in MIME format is written
102 verify signed mail. Expects a signed mail message on input and outputs
103 the signed data. Both clear text and opaque signing is supported.
107 takes an input message and writes out a PEM encoded CMS structure.
111 resign a message: take an existing message and one or more new signers.
113 =item B<-data_create>
115 Create a CMS B<Data> type.
119 B<Data> type and output the content.
121 =item B<-digest_create>
123 Create a CMS B<DigestedData> type.
125 =item B<-digest_verify>
127 Verify a CMS B<DigestedData> type and output the content.
131 Create a CMS B<CompressedData> type. OpenSSL must be compiled with B<zlib>
132 support for this option to work, otherwise it will output an error.
136 Uncompress a CMS B<CompressedData> type and output the content. OpenSSL must be
137 compiled with B<zlib> support for this option to work, otherwise it will
140 =item B<-EncryptedData_encrypt>
142 Encrypt suppled content using supplied symmetric key and algorithm using a CMS
143 B<EncrytedData> type and output the content.
145 =item B<-sign_receipt>
147 Generate and output a signed receipt for the supplied message. The input
148 message B<must> contain a signed receipt request. Functionality is otherwise
149 similar to the B<-sign> operation.
151 =item B<-verify_receipt receipt>
153 Verify a signed receipt in filename B<receipt>. The input message B<must>
154 contain the original receipt request. Functionality is otherwise similar
155 to the B<-verify> operation.
157 =item B<-in filename>
159 the input message to be encrypted or signed or the message to be decrypted
162 =item B<-inform SMIME|PEM|DER>
164 this specifies the input format for the CMS structure. The default
165 is B<SMIME> which reads an S/MIME format message. B<PEM> and B<DER>
166 format change this to expect PEM and DER format CMS structures
167 instead. This currently only affects the input format of the CMS
168 structure, if no CMS structure is being input (for example with
169 B<-encrypt> or B<-sign>) this option has no effect.
171 =item B<-rctform SMIME|PEM|DER>
173 specify the format for a signed receipt for use with the B<-receipt_verify>
176 =item B<-out filename>
178 the message text that has been decrypted or verified or the output MIME
179 format message that has been signed or verified.
181 =item B<-outform SMIME|PEM|DER>
183 this specifies the output format for the CMS structure. The default
184 is B<SMIME> which writes an S/MIME format message. B<PEM> and B<DER>
185 format change this to write PEM and DER format CMS structures
186 instead. This currently only affects the output format of the CMS
187 structure, if no CMS structure is being output (for example with
188 B<-verify> or B<-decrypt>) this option has no effect.
190 =item B<-stream -indef -noindef>
192 the B<-stream> and B<-indef> options are equivalent and enable streaming I/O
193 for encoding operations. This permits single pass processing of data without
194 the need to hold the entire contents in memory, potentially supporting very
195 large files. Streaming is automatically set for S/MIME signing with detached
196 data if the output format is B<SMIME> it is currently off by default for all
201 disable streaming I/O where it would produce and indefinite length constructed
202 encoding. This option currently has no effect. In future streaming will be
203 enabled by default on all relevant operations and this option will disable it.
205 =item B<-content filename>
207 This specifies a file containing the detached content, this is only
208 useful with the B<-verify> command. This is only usable if the CMS
209 structure is using the detached signature form where the content is
210 not included. This option will override any content if the input format
211 is S/MIME and it uses the multipart/signed MIME content type.
215 this option adds plain text (text/plain) MIME headers to the supplied
216 message if encrypting or signing. If decrypting or verifying it strips
217 off text headers: if the decrypted or verified message is not of MIME
218 type text/plain then an error occurs.
222 for the B<-cmsout> operation do not output the parsed CMS structure. This
223 is useful when combined with the B<-print> option or if the syntax of the CMS
224 structure is being checked.
228 for the B<-cmsout> operation print out all fields of the CMS structure. This
229 is mainly useful for testing purposes.
231 =item B<-CAfile file>
233 a file containing trusted CA certificates, only used with B<-verify>.
237 a directory containing trusted CA certificates, only used with
238 B<-verify>. This directory must be a standard certificate directory: that
239 is a hash of each subject name (using B<x509 -hash>) should be linked
244 digest algorithm to use when signing or resigning. If not present then the
245 default digest algorithm for the signing key will be used (usually SHA1).
249 the encryption algorithm to use. For example triple DES (168 bits) - B<-des3>
250 or 256 bit AES - B<-aes256>. Any standard algorithm name (as used by the
251 EVP_get_cipherbyname() function) can also be used preceded by a dash, for
252 example B<-aes_128_cbc>. See L<B<enc>|enc(1)> for a list of ciphers
253 supported by your version of OpenSSL.
255 If not specified triple DES is used. Only used with B<-encrypt> and
256 B<-EncryptedData_create> commands.
260 when verifying a message normally certificates (if any) included in
261 the message are searched for the signing certificate. With this option
262 only the certificates specified in the B<-certfile> option are used.
263 The supplied certificates can still be used as untrusted CAs however.
265 =item B<-no_signer_cert_verify>
267 do not verify the signers certificate of a signed message.
271 when signing a message the signer's certificate is normally included
272 with this option it is excluded. This will reduce the size of the
273 signed message but the verifier must have a copy of the signers certificate
274 available locally (passed using the B<-certfile> option for example).
278 normally when a message is signed a set of attributes are included which
279 include the signing time and supported symmetric algorithms. With this
280 option they are not included.
284 exclude the list of supported algorithms from signed attributes, other options
285 such as signing time and content type are still included.
289 normally the input message is converted to "canonical" format which is
290 effectively using CR and LF as end of line: as required by the S/MIME
291 specification. When this option is present no translation occurs. This
292 is useful when handling binary data which may not be in MIME format.
296 when signing a message use opaque signing: this form is more resistant
297 to translation by mail relays but it cannot be read by mail agents that
298 do not support S/MIME. Without this option cleartext signing with
299 the MIME type multipart/signed is used.
301 =item B<-certfile file>
303 allows additional certificates to be specified. When signing these will
304 be included with the message. When verifying these will be searched for
305 the signers certificates. The certificates should be in PEM format.
307 =item B<-certsout file>
309 any certificates contained in the message are written to B<file>.
311 =item B<-signer file>
313 a signing certificate when signing or resigning a message, this option can be
314 used multiple times if more than one signer is required. If a message is being
315 verified then the signers certificates will be written to this file if the
316 verification was successful.
320 when decrypting a message this specifies the recipients certificate. The
321 certificate must match one of the recipients of the message or an error
324 When encrypting a message this option may be used multiple times to specify
325 each recipient. This form B<must> be used if customised parameters are
326 required (for example to specify RSA-OAEP).
330 use subject key identifier to identify certificates instead of issuer name and
331 serial number. The supplied certificate B<must> include a subject key
332 identifier extension. Supported by B<-sign> and B<-encrypt> options.
334 =item B<-receipt_request_all -receipt_request_first>
336 for B<-sign> option include a signed receipt request. Indicate requests should
337 be provided by all receipient or first tier recipients (those mailed directly
338 and not from a mailing list). Ignored it B<-receipt_request_from> is included.
340 =item B<-receipt_request_from emailaddress>
342 for B<-sign> option include a signed receipt request. Add an explicit email
343 address where receipts should be supplied.
345 =item B<-receipt_request_to emailaddress>
347 Add an explicit email address where signed receipts should be sent to. This
348 option B<must> but supplied if a signed receipt it requested.
350 =item B<-receipt_request_print>
352 For the B<-verify> operation print out the contents of any signed receipt
355 =item B<-secretkey key>
357 specify symmetric key to use. The key must be supplied in hex format and be
358 consistent with the algorithm used. Supported by the B<-EncryptedData_encrypt>
359 B<-EncrryptedData_decrypt>, B<-encrypt> and B<-decrypt> options. When used
360 with B<-encrypt> or B<-decrypt> the supplied key is used to wrap or unwrap the
361 content encryption key using an AES key in the B<KEKRecipientInfo> type.
363 =item B<-secretkeyid id>
365 the key identifier for the supplied symmetric key for B<KEKRecipientInfo> type.
366 This option B<must> be present if the B<-secretkey> option is used with
367 B<-encrypt>. With B<-decrypt> operations the B<id> is used to locate the
368 relevant key if it is not supplied then an attempt is used to decrypt any
369 B<KEKRecipientInfo> structures.
371 =item B<-econtent_type type>
373 set the encapsulated content type to B<type> if not supplied the B<Data> type
374 is used. The B<type> argument can be any valid OID name in either text or
379 the private key to use when signing or decrypting. This must match the
380 corresponding certificate. If this option is not specified then the
381 private key must be included in the certificate file specified with
382 the B<-recip> or B<-signer> file. When signing this option can be used
383 multiple times to specify successive keys.
385 =item B<-keyopt name:opt>
387 for signing and encryption this option can be used multiple times to
388 set customised parameters for the preceding key or certificate. It can
389 currently be used to set RSA-PSS for signing, RSA-OAEP for encryption
390 or to modify default parameters for ECDH.
394 the private key password source. For more information about the format of B<arg>
395 see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)|openssl(1)>.
397 =item B<-rand file(s)>
399 a file or files containing random data used to seed the random number
400 generator, or an EGD socket (see L<RAND_egd(3)|RAND_egd(3)>).
401 Multiple files can be specified separated by a OS-dependent character.
402 The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for
407 one or more certificates of message recipients: used when encrypting
410 =item B<-to, -from, -subject>
412 the relevant mail headers. These are included outside the signed
413 portion of a message so they may be included manually. If signing
414 then many S/MIME mail clients check the signers certificate's email
415 address matches that specified in the From: address.
417 =item B<-purpose, -ignore_critical, -issuer_checks, -crl_check, -crl_check_all, -policy_check, -extended_crl, -x509_strict, -policy -check_ss_sig>
419 Set various certificate chain valiadition option. See the
420 L<B<verify>|verify(1)> manual page for details.
426 The MIME message must be sent without any blank lines between the
427 headers and the output. Some mail programs will automatically add
428 a blank line. Piping the mail directly to sendmail is one way to
429 achieve the correct format.
431 The supplied message to be signed or encrypted must include the
432 necessary MIME headers or many S/MIME clients wont display it
433 properly (if at all). You can use the B<-text> option to automatically
434 add plain text headers.
436 A "signed and encrypted" message is one where a signed message is
437 then encrypted. This can be produced by encrypting an already signed
438 message: see the examples section.
440 This version of the program only allows one signer per message but it
441 will verify multiple signers on received messages. Some S/MIME clients
442 choke if a message contains multiple signers. It is possible to sign
443 messages "in parallel" by signing an already signed message.
445 The options B<-encrypt> and B<-decrypt> reflect common usage in S/MIME
446 clients. Strictly speaking these process CMS enveloped data: CMS
447 encrypted data is used for other purposes.
449 The B<-resign> option uses an existing message digest when adding a new
450 signer. This means that attributes must be present in at least one existing
451 signer using the same message digest or this operation will fail.
453 The B<-stream> and B<-indef> options enable experimental streaming I/O support.
454 As a result the encoding is BER using indefinite length constructed encoding
455 and no longer DER. Streaming is supported for the B<-encrypt> operation and the
456 B<-sign> operation if the content is not detached.
458 Streaming is always used for the B<-sign> operation with detached data but
459 since the content is no longer part of the CMS structure the encoding
468 the operation was completely successfully.
472 an error occurred parsing the command options.
476 one of the input files could not be read.
480 an error occurred creating the CMS file or when reading the MIME
485 an error occurred decrypting or verifying the message.
489 the message was verified correctly but an error occurred writing out
490 the signers certificates.
494 =head1 COMPATIBILITY WITH PKCS#7 format.
496 The B<smime> utility can only process the older B<PKCS#7> format. The B<cms>
497 utility supports Cryptographic Message Syntax format. Use of some features
498 will result in messages which cannot be processed by applications which only
499 support the older format. These are detailed below.
501 The use of the B<-keyid> option with B<-sign> or B<-encrypt>.
503 The B<-outform PEM> option uses different headers.
505 The B<-compress> option.
507 The B<-secretkey> option when used with B<-encrypt>.
509 The use of PSS with B<-sign>.
511 The use of OAEP or non-RSA keys with B<-encrypt>.
513 Additionally the B<-EncryptedData_create> and B<-data_create> type cannot
514 be processed by the older B<smime> command.
518 Create a cleartext signed message:
520 openssl cms -sign -in message.txt -text -out mail.msg \
523 Create an opaque signed message
525 openssl cms -sign -in message.txt -text -out mail.msg -nodetach \
528 Create a signed message, include some additional certificates and
529 read the private key from another file:
531 openssl cms -sign -in in.txt -text -out mail.msg \
532 -signer mycert.pem -inkey mykey.pem -certfile mycerts.pem
534 Create a signed message with two signers, use key identifier:
536 openssl cms -sign -in message.txt -text -out mail.msg \
537 -signer mycert.pem -signer othercert.pem -keyid
539 Send a signed message under Unix directly to sendmail, including headers:
541 openssl cms -sign -in in.txt -text -signer mycert.pem \
542 -from steve@openssl.org -to someone@somewhere \
543 -subject "Signed message" | sendmail someone@somewhere
545 Verify a message and extract the signer's certificate if successful:
547 openssl cms -verify -in mail.msg -signer user.pem -out signedtext.txt
549 Send encrypted mail using triple DES:
551 openssl cms -encrypt -in in.txt -from steve@openssl.org \
552 -to someone@somewhere -subject "Encrypted message" \
553 -des3 user.pem -out mail.msg
555 Sign and encrypt mail:
557 openssl cms -sign -in ml.txt -signer my.pem -text \
558 | openssl cms -encrypt -out mail.msg \
559 -from steve@openssl.org -to someone@somewhere \
560 -subject "Signed and Encrypted message" -des3 user.pem
562 Note: the encryption command does not include the B<-text> option because the
563 message being encrypted already has MIME headers.
567 openssl cms -decrypt -in mail.msg -recip mycert.pem -inkey key.pem
569 The output from Netscape form signing is a PKCS#7 structure with the
570 detached signature format. You can use this program to verify the
571 signature by line wrapping the base64 encoded structure and surrounding
574 -----BEGIN PKCS7-----
577 and using the command,
579 openssl cms -verify -inform PEM -in signature.pem -content content.txt
581 alternatively you can base64 decode the signature and use
583 openssl cms -verify -inform DER -in signature.der -content content.txt
585 Create an encrypted message using 128 bit Camellia:
587 openssl cms -encrypt -in plain.txt -camellia128 -out mail.msg cert.pem
589 Add a signer to an existing message:
591 openssl cms -resign -in mail.msg -signer newsign.pem -out mail2.msg
593 Sign mail using RSA-PSS:
595 openssl cms -sign -in message.txt -text -out mail.msg \
596 -signer mycert.pem -keyopt rsa_padding_mode:pss
598 Create encrypted mail using RSA-OAEP:
600 openssl cms -encrypt -in plain.txt -out mail.msg \
601 -recip cert.pem -keyopt rsa_padding_mode:oaep
603 Use SHA256 KDF with an ECDH certificate:
605 openssl cms -encrypt -in plain.txt -out mail.msg \
606 -recip ecdhcert.pem -keyopt ecdh_kdf_md:sha256
610 The MIME parser isn't very clever: it seems to handle most messages that I've
611 thrown at it but it may choke on others.
613 The code currently will only write out the signer's certificate to a file: if
614 the signer has a separate encryption certificate this must be manually
615 extracted. There should be some heuristic that determines the correct
616 encryption certificate.
618 Ideally a database should be maintained of a certificates for each email
621 The code doesn't currently take note of the permitted symmetric encryption
622 algorithms as supplied in the SMIMECapabilities signed attribute. this means the
623 user has to manually include the correct encryption algorithm. It should store
624 the list of permitted ciphers in a database and only use those.
626 No revocation checking is done on the signer's certificate.
630 The use of multiple B<-signer> options and the B<-resign> command were first
631 added in OpenSSL 1.0.0
633 The B<keyopt> option was first added in OpenSSL 1.1.0
635 The use of B<-recip> to specify the recipient when encrypting mail was first
636 added to OpenSSL 1.1.0
638 Support for RSA-OAEP and RSA-PSS was first added to OpenSSL 1.1.0.
640 The use of non-RSA keys with B<-encrypt> and B<-decrypt> was first added