31 [B<-inform SMIME|PEM|DER>]
35 [B<-outform SMIME|PEM|DER>]
50 The B<cms> command handles S/MIME v3.1 mail. It can encrypt, decrypt, sign and
51 verify, compress and uncompress S/MIME messages.
53 =head1 COMMAND OPTIONS
55 There are twelve operation options that set the type of operation to be
56 performed. The meaning of the other options varies according to the operation
63 encrypt mail for the given recipient certificates. Input file is the message
64 to be encrypted. The output file is the encrypted mail in MIME format. The
65 actual CMS type is <B>EnvelopedData<B>.
69 decrypt mail using the supplied certificate and private key. Expects an
70 encrypted mail message in MIME format for the input file. The decrypted mail
71 is written to the output file.
75 sign mail using the supplied certificate and private key. Input file is
76 the message to be signed. The signed message in MIME format is written
81 verify signed mail. Expects a signed mail message on input and outputs
82 the signed data. Both clear text and opaque signing is supported.
86 takes an input message and writes out a PEM encoded CMS structure.
90 resign a message: take an existing message and one or more new signers.
94 Create a CMS B<Data> type.
98 B<Data> type and output the content.
100 =item B<-digest_create>
102 Create a CMS B<DigestedData> type.
104 =item B<-digest_verify>
106 Verify a CMS B<DigestedData> type and output the content.
110 Create a CMS B<CompressedData> type. OpenSSL must be compiled with B<zlib>
111 support for this option to work, otherwise it will output an error.
115 Uncompress a CMS B<CompressedData> type and output the content. OpenSSL must be
116 compiled with B<zlib> support for this option to work, otherwise it will
119 =item B<-EncryptedData_encrypt>
121 Encrypt suppled content using supplied symmetric key and algorithm using a CMS
122 B<EncrytedData> type and output the content.
124 =item B<-in filename>
126 the input message to be encrypted or signed or the MIME message to
127 be decrypted or verified.
129 =item B<-inform SMIME|PEM|DER>
131 this specifies the input format for the CMS structure. The default
132 is B<SMIME> which reads an S/MIME format message. B<PEM> and B<DER>
133 format change this to expect PEM and DER format CMS structures
134 instead. This currently only affects the input format of the CMS
135 structure, if no CMS structure is being input (for example with
136 B<-encrypt> or B<-sign>) this option has no effect.
138 =item B<-out filename>
140 the message text that has been decrypted or verified or the output MIME
141 format message that has been signed or verified.
143 =item B<-outform SMIME|PEM|DER>
145 this specifies the output format for the CMS structure. The default
146 is B<SMIME> which write an S/MIME format message. B<PEM> and B<DER>
147 format change this to write PEM and DER format CMS structures
148 instead. This currently only affects the output format of the CMS
149 structure, if no CMS structure is being output (for example with
150 B<-verify> or B<-decrypt>) this option has no effect.
152 =item B<-stream -indef -noindef>
154 the B<-stream> and B<-indef> options are equivalent and enable streaming I/O
155 for encoding operations. This permits single pass processing of data without
156 the need to hold the entire contents in memory, potentially supporting very
157 large files. Streaming is automatically set for S/MIME signing with detached
158 data if the output format is B<SMIME> it is currently off by default for all
163 disable streaming I/O where it would produce and indefinite length constructed
164 encoding. This option currently has no effect. In future streaming will be
165 enabled by default on all relevant operations and this option will disable it.
167 =item B<-content filename>
169 This specifies a file containing the detached content, this is only
170 useful with the B<-verify> command. This is only usable if the CMS
171 structure is using the detached signature form where the content is
172 not included. This option will override any content if the input format
173 is S/MIME and it uses the multipart/signed MIME content type.
177 this option adds plain text (text/plain) MIME headers to the supplied
178 message if encrypting or signing. If decrypting or verifying it strips
179 off text headers: if the decrypted or verified message is not of MIME
180 type text/plain then an error occurs.
182 =item B<-CAfile file>
184 a file containing trusted CA certificates, only used with B<-verify>.
188 a directory containing trusted CA certificates, only used with
189 B<-verify>. This directory must be a standard certificate directory: that
190 is a hash of each subject name (using B<x509 -hash>) should be linked
195 digest algorithm to use when signing or resigning. If not present then the
196 default digest algorithm for the signing key will be used (usually SHA1).
198 =item B<-des -des3 -rc2-40 -rc2-64 -rc2-128 -aes128 -aes192 -aes256 -camellia128 -camellia192 -camellia256>
200 the encryption algorithm to use. DES (56 bits), triple DES (168 bits), 40, 64
201 or 128 bit RC2, 128, 192 or 256 bit AES, or 128, 192 or 256 bit Camellia
202 respectively. Any other cipher name (as recognized by the
203 EVP_get_cipherbyname() function) can also be used preceded by a dash, for
204 example B<-aes_128_cbc>.
206 If not specified triple DES is used. Only used with B<-encrypt> and
207 B<-EncryptedData_create> commands.
211 when verifying a message normally certificates (if any) included in
212 the message are searched for the signing certificate. With this option
213 only the certificates specified in the B<-certfile> option are used.
214 The supplied certificates can still be used as untrusted CAs however.
218 do not verify the signers certificate of a signed message.
222 when signing a message the signer's certificate is normally included
223 with this option it is excluded. This will reduce the size of the
224 signed message but the verifier must have a copy of the signers certificate
225 available locally (passed using the B<-certfile> option for example).
229 normally when a message is signed a set of attributes are included which
230 include the signing time and supported symmetric algorithms. With this
231 option they are not included.
235 exclude the list of supported algorithms from signed attributes, other options
236 such as signing time and content type are still included.
240 normally the input message is converted to "canonical" format which is
241 effectively using CR and LF as end of line: as required by the S/MIME
242 specification. When this option is present no translation occurs. This
243 is useful when handling binary data which may not be in MIME format.
247 when signing a message use opaque signing: this form is more resistant
248 to translation by mail relays but it cannot be read by mail agents that
249 do not support S/MIME. Without this option cleartext signing with
250 the MIME type multipart/signed is used.
252 =item B<-certfile file>
254 allows additional certificates to be specified. When signing these will
255 be included with the message. When verifying these will be searched for
256 the signers certificates. The certificates should be in PEM format.
258 =item B<-signer file>
260 a signing certificate when signing or resigning a message, this option can be
261 used multiple times if more than one signer is required. If a message is being
262 verified then the signers certificates will be written to this file if the
263 verification was successful.
267 the recipients certificate when decrypting a message. This certificate
268 must match one of the recipients of the message or an error occurs.
272 use subject key identifier to identify certificates instead of issuer name and
273 serial number. The supplied certificate B<must> include a subject key
274 identifier extension. Supported by B<-sign> and B<-encrypt> options.
276 =item B<-secretkey key>
278 specify symmetric key to use. The key must be supplied in hex format and be
279 consistent with the algorithm used. Supported by the B<-EncryptedData_encrypt>
280 B<-EncrryptedData_decrypt>, B<-encrypt> and B<-decrypt> options. When used
281 with B<-encrypt> or B<-decrypt> the supplied key is used to wrap or unwrap the
282 content encryption key using an AES key in the B<KEKRecipientInfo> type.
284 =item B<-secretkeyid id>
286 the key identifier for the supplied symmetric key for B<KEKRecipientInfo> type.
287 This option B<must> be present if the B<-secretkey> option is used with
288 B<-encrypt>. With B<-decrypt> operations the B<id> is used to locate the
289 relevant key if it is not supplied then an attempt is used to decrypt any
290 B<KEKRecipientInfo> structures.
292 =item B<-econtent_type type>
294 set the encapsulated content type to B<type> if not supplied the B<Data> type
295 is used. The B<type> argument can be any valid OID name in either text or
300 the private key to use when signing or decrypting. This must match the
301 corresponding certificate. If this option is not specified then the
302 private key must be included in the certificate file specified with
303 the B<-recip> or B<-signer> file. When signing this option can be used
304 multiple times to specify successive keys.
308 the private key password source. For more information about the format of B<arg>
309 see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)|openssl(1)>.
311 =item B<-rand file(s)>
313 a file or files containing random data used to seed the random number
314 generator, or an EGD socket (see L<RAND_egd(3)|RAND_egd(3)>).
315 Multiple files can be specified separated by a OS-dependent character.
316 The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for
321 one or more certificates of message recipients: used when encrypting
324 =item B<-to, -from, -subject>
326 the relevant mail headers. These are included outside the signed
327 portion of a message so they may be included manually. If signing
328 then many S/MIME mail clients check the signers certificate's email
329 address matches that specified in the From: address.
335 The MIME message must be sent without any blank lines between the
336 headers and the output. Some mail programs will automatically add
337 a blank line. Piping the mail directly to sendmail is one way to
338 achieve the correct format.
340 The supplied message to be signed or encrypted must include the
341 necessary MIME headers or many S/MIME clients wont display it
342 properly (if at all). You can use the B<-text> option to automatically
343 add plain text headers.
345 A "signed and encrypted" message is one where a signed message is
346 then encrypted. This can be produced by encrypting an already signed
347 message: see the examples section.
349 This version of the program only allows one signer per message but it
350 will verify multiple signers on received messages. Some S/MIME clients
351 choke if a message contains multiple signers. It is possible to sign
352 messages "in parallel" by signing an already signed message.
354 The options B<-encrypt> and B<-decrypt> reflect common usage in S/MIME
355 clients. Strictly speaking these process CMS enveloped data: CMS
356 encrypted data is used for other purposes.
358 The B<-resign> option uses an existing message digest when adding a new
359 signer. This means that attributes must be present in at least one existing
360 signer using the same message digest or this operation will fail.
362 The B<-stream> and B<-indef> options enable experimental streaming I/O support.
363 As a result the encoding is BER using indefinite length constructed encoding
364 and no longer DER. Streaming is supported for the B<-encrypt> operation and the
365 B<-sign> operation if the content is not detached.
367 Streaming is always used for the B<-sign> operation with detached data but
368 since the content is no longer part of the CMS structure the encoding
377 the operation was completely successfully.
381 an error occurred parsing the command options.
385 one of the input files could not be read.
389 an error occurred creating the CMS file or when reading the MIME
394 an error occurred decrypting or verifying the message.
398 the message was verified correctly but an error occurred writing out
399 the signers certificates.
403 =head1 COMPATIBILITY WITH PKCS#7 format.
405 The B<smime> utility can only process the older B<PKCS#7> format. The B<cms>
406 utility supports Cryptographic Message Syntax format. Use of some features
407 will result in messages which cannot be processed by applications which only
408 support the older format. These are detailed below.
410 The use of the B<-keyid> option with B<-sign> or B<-encrypt>.
412 The B<-outform PEM> option uses different headers.
414 The B<-compress> option.
416 The B<-secretkey> option when used with B<-encrypt>.
418 Additionally the B<-EncryptedData_create> and B<-data_create> type cannot
419 be processed by the older B<smime> command.
423 Create a cleartext signed message:
425 openssl cms -sign -in message.txt -text -out mail.msg \
428 Create an opaque signed message
430 openssl cms -sign -in message.txt -text -out mail.msg -nodetach \
433 Create a signed message, include some additional certificates and
434 read the private key from another file:
436 openssl cms -sign -in in.txt -text -out mail.msg \
437 -signer mycert.pem -inkey mykey.pem -certfile mycerts.pem
439 Create a signed message with two signers, use key identifier:
441 openssl cms -sign -in message.txt -text -out mail.msg \
442 -signer mycert.pem -signer othercert.pem -keyid
444 Send a signed message under Unix directly to sendmail, including headers:
446 openssl cms -sign -in in.txt -text -signer mycert.pem \
447 -from steve@openssl.org -to someone@somewhere \
448 -subject "Signed message" | sendmail someone@somewhere
450 Verify a message and extract the signer's certificate if successful:
452 openssl cms -verify -in mail.msg -signer user.pem -out signedtext.txt
454 Send encrypted mail using triple DES:
456 openssl cms -encrypt -in in.txt -from steve@openssl.org \
457 -to someone@somewhere -subject "Encrypted message" \
458 -des3 user.pem -out mail.msg
460 Sign and encrypt mail:
462 openssl cms -sign -in ml.txt -signer my.pem -text \
463 | openssl cms -encrypt -out mail.msg \
464 -from steve@openssl.org -to someone@somewhere \
465 -subject "Signed and Encrypted message" -des3 user.pem
467 Note: the encryption command does not include the B<-text> option because the
468 message being encrypted already has MIME headers.
472 openssl cms -decrypt -in mail.msg -recip mycert.pem -inkey key.pem
474 The output from Netscape form signing is a PKCS#7 structure with the
475 detached signature format. You can use this program to verify the
476 signature by line wrapping the base64 encoded structure and surrounding
479 -----BEGIN PKCS7-----
482 and using the command,
484 openssl cms -verify -inform PEM -in signature.pem -content content.txt
486 alternatively you can base64 decode the signature and use
488 openssl cms -verify -inform DER -in signature.der -content content.txt
490 Create an encrypted message using 128 bit Camellia:
492 openssl cms -encrypt -in plain.txt -camellia128 -out mail.msg cert.pem
494 Add a signer to an existing message:
496 openssl cms -resign -in mail.msg -signer newsign.pem -out mail2.msg
500 The MIME parser isn't very clever: it seems to handle most messages that I've
501 thrown at it but it may choke on others.
503 The code currently will only write out the signer's certificate to a file: if
504 the signer has a separate encryption certificate this must be manually
505 extracted. There should be some heuristic that determines the correct
506 encryption certificate.
508 Ideally a database should be maintained of a certificates for each email
511 The code doesn't currently take note of the permitted symmetric encryption
512 algorithms as supplied in the SMIMECapabilities signed attribute. this means the
513 user has to manually include the correct encryption algorithm. It should store
514 the list of permitted ciphers in a database and only use those.
516 No revocation checking is done on the signer's certificate.
520 The use of multiple B<-signer> options and the B<-resign> command were first
521 added in OpenSSL 0.9.9