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>]
70 The B<cms> command handles S/MIME v3.1 mail. It can encrypt, decrypt, sign and
71 verify, compress and uncompress S/MIME messages.
73 =head1 COMMAND OPTIONS
75 There are fourteen operation options that set the type of operation to be
76 performed. The meaning of the other options varies according to the operation
83 encrypt mail for the given recipient certificates. Input file is the message
84 to be encrypted. The output file is the encrypted mail in MIME format. The
85 actual CMS type is <B>EnvelopedData<B>.
89 decrypt mail using the supplied certificate and private key. Expects an
90 encrypted mail message in MIME format for the input file. The decrypted mail
91 is written to the output file.
93 =item B<-debug_decrypt>
95 this option sets the B<CMS_DEBUG_DECRYPT> flag. This option should be used
96 with caution: see the notes section below.
100 sign mail using the supplied certificate and private key. Input file is
101 the message to be signed. The signed message in MIME format is written
106 verify signed mail. Expects a signed mail message on input and outputs
107 the signed data. Both clear text and opaque signing is supported.
111 takes an input message and writes out a PEM encoded CMS structure.
115 resign a message: take an existing message and one or more new signers.
117 =item B<-data_create>
119 Create a CMS B<Data> type.
123 B<Data> type and output the content.
125 =item B<-digest_create>
127 Create a CMS B<DigestedData> type.
129 =item B<-digest_verify>
131 Verify a CMS B<DigestedData> type and output the content.
135 Create a CMS B<CompressedData> type. OpenSSL must be compiled with B<zlib>
136 support for this option to work, otherwise it will output an error.
140 Uncompress a CMS B<CompressedData> type and output the content. OpenSSL must be
141 compiled with B<zlib> support for this option to work, otherwise it will
144 =item B<-EncryptedData_encrypt>
146 Encrypt content using supplied symmetric key and algorithm using a CMS
147 B<EncrytedData> type and output the content.
149 =item B<-sign_receipt>
151 Generate and output a signed receipt for the supplied message. The input
152 message B<must> contain a signed receipt request. Functionality is otherwise
153 similar to the B<-sign> operation.
155 =item B<-verify_receipt receipt>
157 Verify a signed receipt in filename B<receipt>. The input message B<must>
158 contain the original receipt request. Functionality is otherwise similar
159 to the B<-verify> operation.
161 =item B<-in filename>
163 the input message to be encrypted or signed or the message to be decrypted
166 =item B<-inform SMIME|PEM|DER>
168 this specifies the input format for the CMS structure. The default
169 is B<SMIME> which reads an S/MIME format message. B<PEM> and B<DER>
170 format change this to expect PEM and DER format CMS structures
171 instead. This currently only affects the input format of the CMS
172 structure, if no CMS structure is being input (for example with
173 B<-encrypt> or B<-sign>) this option has no effect.
175 =item B<-rctform SMIME|PEM|DER>
177 specify the format for a signed receipt for use with the B<-receipt_verify>
180 =item B<-out filename>
182 the message text that has been decrypted or verified or the output MIME
183 format message that has been signed or verified.
185 =item B<-outform SMIME|PEM|DER>
187 this specifies the output format for the CMS structure. The default
188 is B<SMIME> which writes an S/MIME format message. B<PEM> and B<DER>
189 format change this to write PEM and DER format CMS structures
190 instead. This currently only affects the output format of the CMS
191 structure, if no CMS structure is being output (for example with
192 B<-verify> or B<-decrypt>) this option has no effect.
194 =item B<-stream -indef -noindef>
196 the B<-stream> and B<-indef> options are equivalent and enable streaming I/O
197 for encoding operations. This permits single pass processing of data without
198 the need to hold the entire contents in memory, potentially supporting very
199 large files. Streaming is automatically set for S/MIME signing with detached
200 data if the output format is B<SMIME> it is currently off by default for all
205 disable streaming I/O where it would produce and indefinite length constructed
206 encoding. This option currently has no effect. In future streaming will be
207 enabled by default on all relevant operations and this option will disable it.
209 =item B<-content filename>
211 This specifies a file containing the detached content, this is only
212 useful with the B<-verify> command. This is only usable if the CMS
213 structure is using the detached signature form where the content is
214 not included. This option will override any content if the input format
215 is S/MIME and it uses the multipart/signed MIME content type.
219 this option adds plain text (text/plain) MIME headers to the supplied
220 message if encrypting or signing. If decrypting or verifying it strips
221 off text headers: if the decrypted or verified message is not of MIME
222 type text/plain then an error occurs.
226 for the B<-cmsout> operation do not output the parsed CMS structure. This
227 is useful when combined with the B<-print> option or if the syntax of the CMS
228 structure is being checked.
232 for the B<-cmsout> operation print out all fields of the CMS structure. This
233 is mainly useful for testing purposes.
235 =item B<-CAfile file>
237 a file containing trusted CA certificates, only used with B<-verify>.
241 a directory containing trusted CA certificates, only used with
242 B<-verify>. This directory must be a standard certificate directory: that
243 is a hash of each subject name (using B<x509 -hash>) should be linked
248 digest algorithm to use when signing or resigning. If not present then the
249 default digest algorithm for the signing key will be used (usually SHA1).
253 the encryption algorithm to use. For example triple DES (168 bits) - B<-des3>
254 or 256 bit AES - B<-aes256>. Any standard algorithm name (as used by the
255 EVP_get_cipherbyname() function) can also be used preceded by a dash, for
256 example B<-aes_128_cbc>. See L<B<enc>|enc(1)> for a list of ciphers
257 supported by your version of OpenSSL.
259 If not specified triple DES is used. Only used with B<-encrypt> and
260 B<-EncryptedData_create> commands.
264 when verifying a message normally certificates (if any) included in
265 the message are searched for the signing certificate. With this option
266 only the certificates specified in the B<-certfile> option are used.
267 The supplied certificates can still be used as untrusted CAs however.
269 =item B<-no_signer_cert_verify>
271 do not verify the signers certificate of a signed message.
275 when signing a message the signer's certificate is normally included
276 with this option it is excluded. This will reduce the size of the
277 signed message but the verifier must have a copy of the signers certificate
278 available locally (passed using the B<-certfile> option for example).
282 normally when a message is signed a set of attributes are included which
283 include the signing time and supported symmetric algorithms. With this
284 option they are not included.
288 exclude the list of supported algorithms from signed attributes, other options
289 such as signing time and content type are still included.
293 normally the input message is converted to "canonical" format which is
294 effectively using CR and LF as end of line: as required by the S/MIME
295 specification. When this option is present no translation occurs. This
296 is useful when handling binary data which may not be in MIME format.
300 when signing a message use opaque signing: this form is more resistant
301 to translation by mail relays but it cannot be read by mail agents that
302 do not support S/MIME. Without this option cleartext signing with
303 the MIME type multipart/signed is used.
305 =item B<-certfile file>
307 allows additional certificates to be specified. When signing these will
308 be included with the message. When verifying these will be searched for
309 the signers certificates. The certificates should be in PEM format.
311 =item B<-certsout file>
313 any certificates contained in the message are written to B<file>.
315 =item B<-signer file>
317 a signing certificate when signing or resigning a message, this option can be
318 used multiple times if more than one signer is required. If a message is being
319 verified then the signers certificates will be written to this file if the
320 verification was successful.
324 the recipients certificate when decrypting a message. This certificate
325 must match one of the recipients of the message or an error occurs.
329 use subject key identifier to identify certificates instead of issuer name and
330 serial number. The supplied certificate B<must> include a subject key
331 identifier extension. Supported by B<-sign> and B<-encrypt> options.
333 =item B<-receipt_request_all -receipt_request_first>
335 for B<-sign> option include a signed receipt request. Indicate requests should
336 be provided by all receipient or first tier recipients (those mailed directly
337 and not from a mailing list). Ignored it B<-receipt_request_from> is included.
339 =item B<-receipt_request_from emailaddress>
341 for B<-sign> option include a signed receipt request. Add an explicit email
342 address where receipts should be supplied.
344 =item B<-receipt_request_to emailaddress>
346 Add an explicit email address where signed receipts should be sent to. This
347 option B<must> but supplied if a signed receipt it requested.
349 =item B<-receipt_request_print>
351 For the B<-verify> operation print out the contents of any signed receipt
354 =item B<-secretkey key>
356 specify symmetric key to use. The key must be supplied in hex format and be
357 consistent with the algorithm used. Supported by the B<-EncryptedData_encrypt>
358 B<-EncrryptedData_decrypt>, B<-encrypt> and B<-decrypt> options. When used
359 with B<-encrypt> or B<-decrypt> the supplied key is used to wrap or unwrap the
360 content encryption key using an AES key in the B<KEKRecipientInfo> type.
362 =item B<-secretkeyid id>
364 the key identifier for the supplied symmetric key for B<KEKRecipientInfo> type.
365 This option B<must> be present if the B<-secretkey> option is used with
366 B<-encrypt>. With B<-decrypt> operations the B<id> is used to locate the
367 relevant key if it is not supplied then an attempt is used to decrypt any
368 B<KEKRecipientInfo> structures.
370 =item B<-econtent_type type>
372 set the encapsulated content type to B<type> if not supplied the B<Data> type
373 is used. The B<type> argument can be any valid OID name in either text or
378 the private key to use when signing or decrypting. This must match the
379 corresponding certificate. If this option is not specified then the
380 private key must be included in the certificate file specified with
381 the B<-recip> or B<-signer> file. When signing this option can be used
382 multiple times to specify successive keys.
386 the private key password source. For more information about the format of B<arg>
387 see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)|openssl(1)>.
389 =item B<-rand file(s)>
391 a file or files containing random data used to seed the random number
392 generator, or an EGD socket (see L<RAND_egd(3)|RAND_egd(3)>).
393 Multiple files can be specified separated by a OS-dependent character.
394 The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for
399 one or more certificates of message recipients: used when encrypting
402 =item B<-to, -from, -subject>
404 the relevant mail headers. These are included outside the signed
405 portion of a message so they may be included manually. If signing
406 then many S/MIME mail clients check the signers certificate's email
407 address matches that specified in the From: address.
409 =item B<-purpose, -ignore_critical, -issuer_checks, -crl_check, -crl_check_all, -policy_check, -extended_crl, -x509_strict, -policy -check_ss_sig>
411 Set various certificate chain valiadition option. See the
412 L<B<verify>|verify(1)> manual page for details.
418 The MIME message must be sent without any blank lines between the
419 headers and the output. Some mail programs will automatically add
420 a blank line. Piping the mail directly to sendmail is one way to
421 achieve the correct format.
423 The supplied message to be signed or encrypted must include the
424 necessary MIME headers or many S/MIME clients wont display it
425 properly (if at all). You can use the B<-text> option to automatically
426 add plain text headers.
428 A "signed and encrypted" message is one where a signed message is
429 then encrypted. This can be produced by encrypting an already signed
430 message: see the examples section.
432 This version of the program only allows one signer per message but it
433 will verify multiple signers on received messages. Some S/MIME clients
434 choke if a message contains multiple signers. It is possible to sign
435 messages "in parallel" by signing an already signed message.
437 The options B<-encrypt> and B<-decrypt> reflect common usage in S/MIME
438 clients. Strictly speaking these process CMS enveloped data: CMS
439 encrypted data is used for other purposes.
441 The B<-resign> option uses an existing message digest when adding a new
442 signer. This means that attributes must be present in at least one existing
443 signer using the same message digest or this operation will fail.
445 The B<-stream> and B<-indef> options enable experimental streaming I/O support.
446 As a result the encoding is BER using indefinite length constructed encoding
447 and no longer DER. Streaming is supported for the B<-encrypt> operation and the
448 B<-sign> operation if the content is not detached.
450 Streaming is always used for the B<-sign> operation with detached data but
451 since the content is no longer part of the CMS structure the encoding
454 If the B<-decrypt> option is used without a recipient certificate then an
455 attempt is made to locate the recipient by trying each potential recipient
456 in turn using the supplied private key. To thwart the MMA attack
457 (Bleichenbacher's attack on PKCS #1 v1.5 RSA padding) all recipients are
458 tried whether they succeed or not and if no recipients match the message
459 is "decrypted" using a random key which will typically output garbage.
460 The B<-debug_decrypt> option can be used to disable the MMA attack protection
461 and return an error if no recipient can be found: this option should be used
462 with caution. For a fuller description see L<CMS_decrypt(3)|CMS_decrypt(3)>).
470 the operation was completely successfully.
474 an error occurred parsing the command options.
478 one of the input files could not be read.
482 an error occurred creating the CMS file or when reading the MIME
487 an error occurred decrypting or verifying the message.
491 the message was verified correctly but an error occurred writing out
492 the signers certificates.
496 =head1 COMPATIBILITY WITH PKCS#7 format.
498 The B<smime> utility can only process the older B<PKCS#7> format. The B<cms>
499 utility supports Cryptographic Message Syntax format. Use of some features
500 will result in messages which cannot be processed by applications which only
501 support the older format. These are detailed below.
503 The use of the B<-keyid> option with B<-sign> or B<-encrypt>.
505 The B<-outform PEM> option uses different headers.
507 The B<-compress> option.
509 The B<-secretkey> option when used with B<-encrypt>.
511 Additionally the B<-EncryptedData_create> and B<-data_create> type cannot
512 be processed by the older B<smime> command.
516 Create a cleartext signed message:
518 openssl cms -sign -in message.txt -text -out mail.msg \
521 Create an opaque signed message
523 openssl cms -sign -in message.txt -text -out mail.msg -nodetach \
526 Create a signed message, include some additional certificates and
527 read the private key from another file:
529 openssl cms -sign -in in.txt -text -out mail.msg \
530 -signer mycert.pem -inkey mykey.pem -certfile mycerts.pem
532 Create a signed message with two signers, use key identifier:
534 openssl cms -sign -in message.txt -text -out mail.msg \
535 -signer mycert.pem -signer othercert.pem -keyid
537 Send a signed message under Unix directly to sendmail, including headers:
539 openssl cms -sign -in in.txt -text -signer mycert.pem \
540 -from steve@openssl.org -to someone@somewhere \
541 -subject "Signed message" | sendmail someone@somewhere
543 Verify a message and extract the signer's certificate if successful:
545 openssl cms -verify -in mail.msg -signer user.pem -out signedtext.txt
547 Send encrypted mail using triple DES:
549 openssl cms -encrypt -in in.txt -from steve@openssl.org \
550 -to someone@somewhere -subject "Encrypted message" \
551 -des3 user.pem -out mail.msg
553 Sign and encrypt mail:
555 openssl cms -sign -in ml.txt -signer my.pem -text \
556 | openssl cms -encrypt -out mail.msg \
557 -from steve@openssl.org -to someone@somewhere \
558 -subject "Signed and Encrypted message" -des3 user.pem
560 Note: the encryption command does not include the B<-text> option because the
561 message being encrypted already has MIME headers.
565 openssl cms -decrypt -in mail.msg -recip mycert.pem -inkey key.pem
567 The output from Netscape form signing is a PKCS#7 structure with the
568 detached signature format. You can use this program to verify the
569 signature by line wrapping the base64 encoded structure and surrounding
572 -----BEGIN PKCS7-----
575 and using the command,
577 openssl cms -verify -inform PEM -in signature.pem -content content.txt
579 alternatively you can base64 decode the signature and use
581 openssl cms -verify -inform DER -in signature.der -content content.txt
583 Create an encrypted message using 128 bit Camellia:
585 openssl cms -encrypt -in plain.txt -camellia128 -out mail.msg cert.pem
587 Add a signer to an existing message:
589 openssl cms -resign -in mail.msg -signer newsign.pem -out mail2.msg
593 The MIME parser isn't very clever: it seems to handle most messages that I've
594 thrown at it but it may choke on others.
596 The code currently will only write out the signer's certificate to a file: if
597 the signer has a separate encryption certificate this must be manually
598 extracted. There should be some heuristic that determines the correct
599 encryption certificate.
601 Ideally a database should be maintained of a certificates for each email
604 The code doesn't currently take note of the permitted symmetric encryption
605 algorithms as supplied in the SMIMECapabilities signed attribute. this means the
606 user has to manually include the correct encryption algorithm. It should store
607 the list of permitted ciphers in a database and only use those.
609 No revocation checking is done on the signer's certificate.
613 The use of multiple B<-signer> options and the B<-resign> command were first
614 added in OpenSSL 1.0.0