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>]
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>.
89 Note that no revocation check is done for the recipient cert, so if that
90 key has been compromised, others may be able to decrypt the text.
94 decrypt mail using the supplied certificate and private key. Expects an
95 encrypted mail message in MIME format for the input file. The decrypted mail
96 is written to the output file.
98 =item B<-debug_decrypt>
100 this option sets the B<CMS_DEBUG_DECRYPT> flag. This option should be used
101 with caution: see the notes section below.
105 sign mail using the supplied certificate and private key. Input file is
106 the message to be signed. The signed message in MIME format is written
111 verify signed mail. Expects a signed mail message on input and outputs
112 the signed data. Both clear text and opaque signing is supported.
116 takes an input message and writes out a PEM encoded CMS structure.
120 resign a message: take an existing message and one or more new signers.
122 =item B<-data_create>
124 Create a CMS B<Data> type.
128 B<Data> type and output the content.
130 =item B<-digest_create>
132 Create a CMS B<DigestedData> type.
134 =item B<-digest_verify>
136 Verify a CMS B<DigestedData> type and output the content.
140 Create a CMS B<CompressedData> type. OpenSSL must be compiled with B<zlib>
141 support for this option to work, otherwise it will output an error.
145 Uncompress a CMS B<CompressedData> type and output the content. OpenSSL must be
146 compiled with B<zlib> support for this option to work, otherwise it will
149 =item B<-EncryptedData_encrypt>
151 Encrypt content using supplied symmetric key and algorithm using a CMS
152 B<EncrytedData> type and output the content.
154 =item B<-sign_receipt>
156 Generate and output a signed receipt for the supplied message. The input
157 message B<must> contain a signed receipt request. Functionality is otherwise
158 similar to the B<-sign> operation.
160 =item B<-verify_receipt receipt>
162 Verify a signed receipt in filename B<receipt>. The input message B<must>
163 contain the original receipt request. Functionality is otherwise similar
164 to the B<-verify> operation.
166 =item B<-in filename>
168 the input message to be encrypted or signed or the message to be decrypted
171 =item B<-inform SMIME|PEM|DER>
173 this specifies the input format for the CMS structure. The default
174 is B<SMIME> which reads an S/MIME format message. B<PEM> and B<DER>
175 format change this to expect PEM and DER format CMS structures
176 instead. This currently only affects the input format of the CMS
177 structure, if no CMS structure is being input (for example with
178 B<-encrypt> or B<-sign>) this option has no effect.
180 =item B<-rctform SMIME|PEM|DER>
182 specify the format for a signed receipt for use with the B<-receipt_verify>
185 =item B<-out filename>
187 the message text that has been decrypted or verified or the output MIME
188 format message that has been signed or verified.
190 =item B<-outform SMIME|PEM|DER>
192 this specifies the output format for the CMS structure. The default
193 is B<SMIME> which writes an S/MIME format message. B<PEM> and B<DER>
194 format change this to write PEM and DER format CMS structures
195 instead. This currently only affects the output format of the CMS
196 structure, if no CMS structure is being output (for example with
197 B<-verify> or B<-decrypt>) this option has no effect.
199 =item B<-stream -indef -noindef>
201 the B<-stream> and B<-indef> options are equivalent and enable streaming I/O
202 for encoding operations. This permits single pass processing of data without
203 the need to hold the entire contents in memory, potentially supporting very
204 large files. Streaming is automatically set for S/MIME signing with detached
205 data if the output format is B<SMIME> it is currently off by default for all
210 disable streaming I/O where it would produce and indefinite length constructed
211 encoding. This option currently has no effect. In future streaming will be
212 enabled by default on all relevant operations and this option will disable it.
214 =item B<-content filename>
216 This specifies a file containing the detached content, this is only
217 useful with the B<-verify> command. This is only usable if the CMS
218 structure is using the detached signature form where the content is
219 not included. This option will override any content if the input format
220 is S/MIME and it uses the multipart/signed MIME content type.
224 this option adds plain text (text/plain) MIME headers to the supplied
225 message if encrypting or signing. If decrypting or verifying it strips
226 off text headers: if the decrypted or verified message is not of MIME
227 type text/plain then an error occurs.
231 for the B<-cmsout> operation do not output the parsed CMS structure. This
232 is useful when combined with the B<-print> option or if the syntax of the CMS
233 structure is being checked.
237 for the B<-cmsout> operation print out all fields of the CMS structure. This
238 is mainly useful for testing purposes.
240 =item B<-CAfile file>
242 a file containing trusted CA certificates, only used with B<-verify>.
246 a directory containing trusted CA certificates, only used with
247 B<-verify>. This directory must be a standard certificate directory: that
248 is a hash of each subject name (using B<x509 -hash>) should be linked
253 digest algorithm to use when signing or resigning. If not present then the
254 default digest algorithm for the signing key will be used (usually SHA1).
258 the encryption algorithm to use. For example triple DES (168 bits) - B<-des3>
259 or 256 bit AES - B<-aes256>. Any standard algorithm name (as used by the
260 EVP_get_cipherbyname() function) can also be used preceded by a dash, for
261 example B<-aes_128_cbc>. See L<B<enc>|enc(1)> for a list of ciphers
262 supported by your version of OpenSSL.
264 If not specified triple DES is used. Only used with B<-encrypt> and
265 B<-EncryptedData_create> commands.
269 when verifying a message normally certificates (if any) included in
270 the message are searched for the signing certificate. With this option
271 only the certificates specified in the B<-certfile> option are used.
272 The supplied certificates can still be used as untrusted CAs however.
274 =item B<-no_signer_cert_verify>
276 do not verify the signers certificate of a signed message.
280 when signing a message the signer's certificate is normally included
281 with this option it is excluded. This will reduce the size of the
282 signed message but the verifier must have a copy of the signers certificate
283 available locally (passed using the B<-certfile> option for example).
287 normally when a message is signed a set of attributes are included which
288 include the signing time and supported symmetric algorithms. With this
289 option they are not included.
293 exclude the list of supported algorithms from signed attributes, other options
294 such as signing time and content type are still included.
298 normally the input message is converted to "canonical" format which is
299 effectively using CR and LF as end of line: as required by the S/MIME
300 specification. When this option is present no translation occurs. This
301 is useful when handling binary data which may not be in MIME format.
305 when signing a message use opaque signing: this form is more resistant
306 to translation by mail relays but it cannot be read by mail agents that
307 do not support S/MIME. Without this option cleartext signing with
308 the MIME type multipart/signed is used.
310 =item B<-certfile file>
312 allows additional certificates to be specified. When signing these will
313 be included with the message. When verifying these will be searched for
314 the signers certificates. The certificates should be in PEM format.
316 =item B<-certsout file>
318 any certificates contained in the message are written to B<file>.
320 =item B<-signer file>
322 a signing certificate when signing or resigning a message, this option can be
323 used multiple times if more than one signer is required. If a message is being
324 verified then the signers certificates will be written to this file if the
325 verification was successful.
329 when decrypting a message this specifies the recipients certificate. The
330 certificate must match one of the recipients of the message or an error
333 When encrypting a message this option may be used multiple times to specify
334 each recipient. This form B<must> be used if customised parameters are
335 required (for example to specify RSA-OAEP).
339 use subject key identifier to identify certificates instead of issuer name and
340 serial number. The supplied certificate B<must> include a subject key
341 identifier extension. Supported by B<-sign> and B<-encrypt> options.
343 =item B<-receipt_request_all -receipt_request_first>
345 for B<-sign> option include a signed receipt request. Indicate requests should
346 be provided by all receipient or first tier recipients (those mailed directly
347 and not from a mailing list). Ignored it B<-receipt_request_from> is included.
349 =item B<-receipt_request_from emailaddress>
351 for B<-sign> option include a signed receipt request. Add an explicit email
352 address where receipts should be supplied.
354 =item B<-receipt_request_to emailaddress>
356 Add an explicit email address where signed receipts should be sent to. This
357 option B<must> but supplied if a signed receipt it requested.
359 =item B<-receipt_request_print>
361 For the B<-verify> operation print out the contents of any signed receipt
364 =item B<-secretkey key>
366 specify symmetric key to use. The key must be supplied in hex format and be
367 consistent with the algorithm used. Supported by the B<-EncryptedData_encrypt>
368 B<-EncrryptedData_decrypt>, B<-encrypt> and B<-decrypt> options. When used
369 with B<-encrypt> or B<-decrypt> the supplied key is used to wrap or unwrap the
370 content encryption key using an AES key in the B<KEKRecipientInfo> type.
372 =item B<-secretkeyid id>
374 the key identifier for the supplied symmetric key for B<KEKRecipientInfo> type.
375 This option B<must> be present if the B<-secretkey> option is used with
376 B<-encrypt>. With B<-decrypt> operations the B<id> is used to locate the
377 relevant key if it is not supplied then an attempt is used to decrypt any
378 B<KEKRecipientInfo> structures.
380 =item B<-econtent_type type>
382 set the encapsulated content type to B<type> if not supplied the B<Data> type
383 is used. The B<type> argument can be any valid OID name in either text or
388 the private key to use when signing or decrypting. This must match the
389 corresponding certificate. If this option is not specified then the
390 private key must be included in the certificate file specified with
391 the B<-recip> or B<-signer> file. When signing this option can be used
392 multiple times to specify successive keys.
394 =item B<-keyopt name:opt>
396 for signing and encryption this option can be used multiple times to
397 set customised parameters for the preceding key or certificate. It can
398 currently be used to set RSA-PSS for signing, RSA-OAEP for encryption
399 or to modify default parameters for ECDH.
403 the private key password source. For more information about the format of B<arg>
404 see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)|openssl(1)>.
406 =item B<-rand file(s)>
408 a file or files containing random data used to seed the random number
409 generator, or an EGD socket (see L<RAND_egd(3)|RAND_egd(3)>).
410 Multiple files can be specified separated by a OS-dependent character.
411 The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for
416 one or more certificates of message recipients: used when encrypting
419 =item B<-to, -from, -subject>
421 the relevant mail headers. These are included outside the signed
422 portion of a message so they may be included manually. If signing
423 then many S/MIME mail clients check the signers certificate's email
424 address matches that specified in the From: address.
426 =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>
428 Set various certificate chain valiadition option. See the
429 L<B<verify>|verify(1)> manual page for details.
435 The MIME message must be sent without any blank lines between the
436 headers and the output. Some mail programs will automatically add
437 a blank line. Piping the mail directly to sendmail is one way to
438 achieve the correct format.
440 The supplied message to be signed or encrypted must include the
441 necessary MIME headers or many S/MIME clients wont display it
442 properly (if at all). You can use the B<-text> option to automatically
443 add plain text headers.
445 A "signed and encrypted" message is one where a signed message is
446 then encrypted. This can be produced by encrypting an already signed
447 message: see the examples section.
449 This version of the program only allows one signer per message but it
450 will verify multiple signers on received messages. Some S/MIME clients
451 choke if a message contains multiple signers. It is possible to sign
452 messages "in parallel" by signing an already signed message.
454 The options B<-encrypt> and B<-decrypt> reflect common usage in S/MIME
455 clients. Strictly speaking these process CMS enveloped data: CMS
456 encrypted data is used for other purposes.
458 The B<-resign> option uses an existing message digest when adding a new
459 signer. This means that attributes must be present in at least one existing
460 signer using the same message digest or this operation will fail.
462 The B<-stream> and B<-indef> options enable experimental streaming I/O support.
463 As a result the encoding is BER using indefinite length constructed encoding
464 and no longer DER. Streaming is supported for the B<-encrypt> operation and the
465 B<-sign> operation if the content is not detached.
467 Streaming is always used for the B<-sign> operation with detached data but
468 since the content is no longer part of the CMS structure the encoding
471 If the B<-decrypt> option is used without a recipient certificate then an
472 attempt is made to locate the recipient by trying each potential recipient
473 in turn using the supplied private key. To thwart the MMA attack
474 (Bleichenbacher's attack on PKCS #1 v1.5 RSA padding) all recipients are
475 tried whether they succeed or not and if no recipients match the message
476 is "decrypted" using a random key which will typically output garbage.
477 The B<-debug_decrypt> option can be used to disable the MMA attack protection
478 and return an error if no recipient can be found: this option should be used
479 with caution. For a fuller description see L<CMS_decrypt(3)|CMS_decrypt(3)>).
487 the operation was completely successfully.
491 an error occurred parsing the command options.
495 one of the input files could not be read.
499 an error occurred creating the CMS file or when reading the MIME
504 an error occurred decrypting or verifying the message.
508 the message was verified correctly but an error occurred writing out
509 the signers certificates.
513 =head1 COMPATIBILITY WITH PKCS#7 format.
515 The B<smime> utility can only process the older B<PKCS#7> format. The B<cms>
516 utility supports Cryptographic Message Syntax format. Use of some features
517 will result in messages which cannot be processed by applications which only
518 support the older format. These are detailed below.
520 The use of the B<-keyid> option with B<-sign> or B<-encrypt>.
522 The B<-outform PEM> option uses different headers.
524 The B<-compress> option.
526 The B<-secretkey> option when used with B<-encrypt>.
528 The use of PSS with B<-sign>.
530 The use of OAEP or non-RSA keys with B<-encrypt>.
532 Additionally the B<-EncryptedData_create> and B<-data_create> type cannot
533 be processed by the older B<smime> command.
537 Create a cleartext signed message:
539 openssl cms -sign -in message.txt -text -out mail.msg \
542 Create an opaque signed message
544 openssl cms -sign -in message.txt -text -out mail.msg -nodetach \
547 Create a signed message, include some additional certificates and
548 read the private key from another file:
550 openssl cms -sign -in in.txt -text -out mail.msg \
551 -signer mycert.pem -inkey mykey.pem -certfile mycerts.pem
553 Create a signed message with two signers, use key identifier:
555 openssl cms -sign -in message.txt -text -out mail.msg \
556 -signer mycert.pem -signer othercert.pem -keyid
558 Send a signed message under Unix directly to sendmail, including headers:
560 openssl cms -sign -in in.txt -text -signer mycert.pem \
561 -from steve@openssl.org -to someone@somewhere \
562 -subject "Signed message" | sendmail someone@somewhere
564 Verify a message and extract the signer's certificate if successful:
566 openssl cms -verify -in mail.msg -signer user.pem -out signedtext.txt
568 Send encrypted mail using triple DES:
570 openssl cms -encrypt -in in.txt -from steve@openssl.org \
571 -to someone@somewhere -subject "Encrypted message" \
572 -des3 user.pem -out mail.msg
574 Sign and encrypt mail:
576 openssl cms -sign -in ml.txt -signer my.pem -text \
577 | openssl cms -encrypt -out mail.msg \
578 -from steve@openssl.org -to someone@somewhere \
579 -subject "Signed and Encrypted message" -des3 user.pem
581 Note: the encryption command does not include the B<-text> option because the
582 message being encrypted already has MIME headers.
586 openssl cms -decrypt -in mail.msg -recip mycert.pem -inkey key.pem
588 The output from Netscape form signing is a PKCS#7 structure with the
589 detached signature format. You can use this program to verify the
590 signature by line wrapping the base64 encoded structure and surrounding
593 -----BEGIN PKCS7-----
596 and using the command,
598 openssl cms -verify -inform PEM -in signature.pem -content content.txt
600 alternatively you can base64 decode the signature and use
602 openssl cms -verify -inform DER -in signature.der -content content.txt
604 Create an encrypted message using 128 bit Camellia:
606 openssl cms -encrypt -in plain.txt -camellia128 -out mail.msg cert.pem
608 Add a signer to an existing message:
610 openssl cms -resign -in mail.msg -signer newsign.pem -out mail2.msg
612 Sign mail using RSA-PSS:
614 openssl cms -sign -in message.txt -text -out mail.msg \
615 -signer mycert.pem -keyopt rsa_padding_mode:pss
617 Create encrypted mail using RSA-OAEP:
619 openssl cms -encrypt -in plain.txt -out mail.msg \
620 -recip cert.pem -keyopt rsa_padding_mode:oaep
622 Use SHA256 KDF with an ECDH certificate:
624 openssl cms -encrypt -in plain.txt -out mail.msg \
625 -recip ecdhcert.pem -keyopt ecdh_kdf_md:sha256
629 The MIME parser isn't very clever: it seems to handle most messages that I've
630 thrown at it but it may choke on others.
632 The code currently will only write out the signer's certificate to a file: if
633 the signer has a separate encryption certificate this must be manually
634 extracted. There should be some heuristic that determines the correct
635 encryption certificate.
637 Ideally a database should be maintained of a certificates for each email
640 The code doesn't currently take note of the permitted symmetric encryption
641 algorithms as supplied in the SMIMECapabilities signed attribute. this means the
642 user has to manually include the correct encryption algorithm. It should store
643 the list of permitted ciphers in a database and only use those.
645 No revocation checking is done on the signer's certificate.
649 The use of multiple B<-signer> options and the B<-resign> command were first
650 added in OpenSSL 1.0.0
652 The B<keyopt> option was first added in OpenSSL 1.1.0
654 The use of B<-recip> to specify the recipient when encrypting mail was first
655 added to OpenSSL 1.1.0
657 Support for RSA-OAEP and RSA-PSS was first added to OpenSSL 1.1.0.
659 The use of non-RSA keys with B<-encrypt> and B<-decrypt> was first added
662 The -no_alt_chains options was first added to OpenSSL 1.0.2b.