20 [B<-attime timestamp>]
41 [B<-verify_depth num>]
42 [B<-verify_email email>]
43 [B<-verify_hostname hostname>]
45 [B<-verify_name name>]
50 [B<-inform SMIME|PEM|DER>]
54 [B<-outform SMIME|PEM|DER>]
69 The B<smime> command handles S/MIME mail. It can encrypt, decrypt, sign and
70 verify S/MIME messages.
72 =head1 COMMAND OPTIONS
74 There are six operation options that set the type of operation to be performed.
75 The meaning of the other options varies according to the operation type.
81 encrypt mail for the given recipient certificates. Input file is the message
82 to be encrypted. The output file is the encrypted mail in MIME format.
86 decrypt mail using the supplied certificate and private key. Expects an
87 encrypted mail message in MIME format for the input file. The decrypted mail
88 is written to the output file.
92 sign mail using the supplied certificate and private key. Input file is
93 the message to be signed. The signed message in MIME format is written
98 verify signed mail. Expects a signed mail message on input and outputs
99 the signed data. Both clear text and opaque signing is supported.
103 takes an input message and writes out a PEM encoded PKCS#7 structure.
107 resign a message: take an existing message and one or more new signers.
109 =item B<-in filename>
111 the input message to be encrypted or signed or the MIME message to
112 be decrypted or verified.
114 =item B<-inform SMIME|PEM|DER>
116 this specifies the input format for the PKCS#7 structure. The default
117 is B<SMIME> which reads an S/MIME format message. B<PEM> and B<DER>
118 format change this to expect PEM and DER format PKCS#7 structures
119 instead. This currently only affects the input format of the PKCS#7
120 structure, if no PKCS#7 structure is being input (for example with
121 B<-encrypt> or B<-sign>) this option has no effect.
123 =item B<-out filename>
125 the message text that has been decrypted or verified or the output MIME
126 format message that has been signed or verified.
128 =item B<-outform SMIME|PEM|DER>
130 this specifies the output format for the PKCS#7 structure. The default
131 is B<SMIME> which write an S/MIME format message. B<PEM> and B<DER>
132 format change this to write PEM and DER format PKCS#7 structures
133 instead. This currently only affects the output format of the PKCS#7
134 structure, if no PKCS#7 structure is being output (for example with
135 B<-verify> or B<-decrypt>) this option has no effect.
137 =item B<-stream -indef -noindef>
139 the B<-stream> and B<-indef> options are equivalent and enable streaming I/O
140 for encoding operations. This permits single pass processing of data without
141 the need to hold the entire contents in memory, potentially supporting very
142 large files. Streaming is automatically set for S/MIME signing with detached
143 data if the output format is B<SMIME> it is currently off by default for all
148 disable streaming I/O where it would produce and indefinite length constructed
149 encoding. This option currently has no effect. In future streaming will be
150 enabled by default on all relevant operations and this option will disable it.
152 =item B<-content filename>
154 This specifies a file containing the detached content, this is only
155 useful with the B<-verify> command. This is only usable if the PKCS#7
156 structure is using the detached signature form where the content is
157 not included. This option will override any content if the input format
158 is S/MIME and it uses the multipart/signed MIME content type.
162 this option adds plain text (text/plain) MIME headers to the supplied
163 message if encrypting or signing. If decrypting or verifying it strips
164 off text headers: if the decrypted or verified message is not of MIME
165 type text/plain then an error occurs.
167 =item B<-CAfile file>
169 a file containing trusted CA certificates, only used with B<-verify>.
173 a directory containing trusted CA certificates, only used with
174 B<-verify>. This directory must be a standard certificate directory: that
175 is a hash of each subject name (using B<x509 -hash>) should be linked
180 digest algorithm to use when signing or resigning. If not present then the
181 default digest algorithm for the signing key will be used (usually SHA1).
185 the encryption algorithm to use. For example DES (56 bits) - B<-des>,
186 triple DES (168 bits) - B<-des3>,
187 EVP_get_cipherbyname() function) can also be used preceded by a dash, for
188 example B<-aes_128_cbc>. See L<B<enc>|enc(1)> for list of ciphers
189 supported by your version of OpenSSL.
191 If not specified triple DES is used. Only used with B<-encrypt>.
195 when verifying a message normally certificates (if any) included in
196 the message are searched for the signing certificate. With this option
197 only the certificates specified in the B<-certfile> option are used.
198 The supplied certificates can still be used as untrusted CAs however.
202 do not verify the signers certificate of a signed message.
206 do not do chain verification of signers certificates: that is don't
207 use the certificates in the signed message as untrusted CAs.
211 don't try to verify the signatures on the message.
215 when signing a message the signer's certificate is normally included
216 with this option it is excluded. This will reduce the size of the
217 signed message but the verifier must have a copy of the signers certificate
218 available locally (passed using the B<-certfile> option for example).
222 normally when a message is signed a set of attributes are included which
223 include the signing time and supported symmetric algorithms. With this
224 option they are not included.
228 normally the input message is converted to "canonical" format which is
229 effectively using CR and LF as end of line: as required by the S/MIME
230 specification. When this option is present no translation occurs. This
231 is useful when handling binary data which may not be in MIME format.
235 when signing a message use opaque signing: this form is more resistant
236 to translation by mail relays but it cannot be read by mail agents that
237 do not support S/MIME. Without this option cleartext signing with
238 the MIME type multipart/signed is used.
240 =item B<-certfile file>
242 allows additional certificates to be specified. When signing these will
243 be included with the message. When verifying these will be searched for
244 the signers certificates. The certificates should be in PEM format.
246 =item B<-signer file>
248 a signing certificate when signing or resigning a message, this option can be
249 used multiple times if more than one signer is required. If a message is being
250 verified then the signers certificates will be written to this file if the
251 verification was successful.
255 the recipients certificate when decrypting a message. This certificate
256 must match one of the recipients of the message or an error occurs.
260 the private key to use when signing or decrypting. This must match the
261 corresponding certificate. If this option is not specified then the
262 private key must be included in the certificate file specified with
263 the B<-recip> or B<-signer> file. When signing this option can be used
264 multiple times to specify successive keys.
268 the private key password source. For more information about the format of B<arg>
269 see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)|openssl(1)>.
271 =item B<-rand file(s)>
273 a file or files containing random data used to seed the random number
274 generator, or an EGD socket (see L<RAND_egd(3)|RAND_egd(3)>).
275 Multiple files can be specified separated by a OS-dependent character.
276 The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for
281 one or more certificates of message recipients: used when encrypting
284 =item B<-to, -from, -subject>
286 the relevant mail headers. These are included outside the signed
287 portion of a message so they may be included manually. If signing
288 then many S/MIME mail clients check the signers certificate's email
289 address matches that specified in the From: address.
291 =item B<-attime>, B<-check_ss_sig>, B<-crl_check>, B<-crl_check_all>,
292 B<explicit_policy>, B<-extended_crl>, B<-ignore_critical>, B<-inhibit_any>,
293 B<-inhibit_map>, B<-issuer_checks>, B<-partial_chain>, B<-policy>,
294 B<-policy_check>, B<-policy_print>, B<-purpose>, B<-suiteB_128>,
295 B<-suiteB_128_only>, B<-suiteB_192>, B<-trusted_first>, B<-no_alt_chains>,
296 B<-use_deltas>, B<-verify_depth>, B<-verify_email>, B<-verify_hostname>,
297 B<-verify_ip>, B<-verify_name>, B<-x509_strict>
299 Set various options of certificate chain verification. See
300 L<B<verify>|verify(1)> manual page for details.
306 The MIME message must be sent without any blank lines between the
307 headers and the output. Some mail programs will automatically add
308 a blank line. Piping the mail directly to sendmail is one way to
309 achieve the correct format.
311 The supplied message to be signed or encrypted must include the
312 necessary MIME headers or many S/MIME clients wont display it
313 properly (if at all). You can use the B<-text> option to automatically
314 add plain text headers.
316 A "signed and encrypted" message is one where a signed message is
317 then encrypted. This can be produced by encrypting an already signed
318 message: see the examples section.
320 This version of the program only allows one signer per message but it
321 will verify multiple signers on received messages. Some S/MIME clients
322 choke if a message contains multiple signers. It is possible to sign
323 messages "in parallel" by signing an already signed message.
325 The options B<-encrypt> and B<-decrypt> reflect common usage in S/MIME
326 clients. Strictly speaking these process PKCS#7 enveloped data: PKCS#7
327 encrypted data is used for other purposes.
329 The B<-resign> option uses an existing message digest when adding a new
330 signer. This means that attributes must be present in at least one existing
331 signer using the same message digest or this operation will fail.
333 The B<-stream> and B<-indef> options enable experimental streaming I/O support.
334 As a result the encoding is BER using indefinite length constructed encoding
335 and no longer DER. Streaming is supported for the B<-encrypt> operation and the
336 B<-sign> operation if the content is not detached.
338 Streaming is always used for the B<-sign> operation with detached data but
339 since the content is no longer part of the PKCS#7 structure the encoding
348 the operation was completely successfully.
352 an error occurred parsing the command options.
356 one of the input files could not be read.
360 an error occurred creating the PKCS#7 file or when reading the MIME
365 an error occurred decrypting or verifying the message.
369 the message was verified correctly but an error occurred writing out
370 the signers certificates.
376 Create a cleartext signed message:
378 openssl smime -sign -in message.txt -text -out mail.msg \
381 Create an opaque signed message:
383 openssl smime -sign -in message.txt -text -out mail.msg -nodetach \
386 Create a signed message, include some additional certificates and
387 read the private key from another file:
389 openssl smime -sign -in in.txt -text -out mail.msg \
390 -signer mycert.pem -inkey mykey.pem -certfile mycerts.pem
392 Create a signed message with two signers:
394 openssl smime -sign -in message.txt -text -out mail.msg \
395 -signer mycert.pem -signer othercert.pem
397 Send a signed message under Unix directly to sendmail, including headers:
399 openssl smime -sign -in in.txt -text -signer mycert.pem \
400 -from steve@openssl.org -to someone@somewhere \
401 -subject "Signed message" | sendmail someone@somewhere
403 Verify a message and extract the signer's certificate if successful:
405 openssl smime -verify -in mail.msg -signer user.pem -out signedtext.txt
407 Send encrypted mail using triple DES:
409 openssl smime -encrypt -in in.txt -from steve@openssl.org \
410 -to someone@somewhere -subject "Encrypted message" \
411 -des3 user.pem -out mail.msg
413 Sign and encrypt mail:
415 openssl smime -sign -in ml.txt -signer my.pem -text \
416 | openssl smime -encrypt -out mail.msg \
417 -from steve@openssl.org -to someone@somewhere \
418 -subject "Signed and Encrypted message" -des3 user.pem
420 Note: the encryption command does not include the B<-text> option because the
421 message being encrypted already has MIME headers.
425 openssl smime -decrypt -in mail.msg -recip mycert.pem -inkey key.pem
427 The output from Netscape form signing is a PKCS#7 structure with the
428 detached signature format. You can use this program to verify the
429 signature by line wrapping the base64 encoded structure and surrounding
432 -----BEGIN PKCS7-----
435 and using the command:
437 openssl smime -verify -inform PEM -in signature.pem -content content.txt
439 Alternatively you can base64 decode the signature and use:
441 openssl smime -verify -inform DER -in signature.der -content content.txt
443 Create an encrypted message using 128 bit Camellia:
445 openssl smime -encrypt -in plain.txt -camellia128 -out mail.msg cert.pem
447 Add a signer to an existing message:
449 openssl smime -resign -in mail.msg -signer newsign.pem -out mail2.msg
453 The MIME parser isn't very clever: it seems to handle most messages that I've
454 thrown at it but it may choke on others.
456 The code currently will only write out the signer's certificate to a file: if
457 the signer has a separate encryption certificate this must be manually
458 extracted. There should be some heuristic that determines the correct
459 encryption certificate.
461 Ideally a database should be maintained of a certificates for each email
464 The code doesn't currently take note of the permitted symmetric encryption
465 algorithms as supplied in the SMIMECapabilities signed attribute. This means the
466 user has to manually include the correct encryption algorithm. It should store
467 the list of permitted ciphers in a database and only use those.
469 No revocation checking is done on the signer's certificate.
471 The current code can only handle S/MIME v2 messages, the more complex S/MIME v3
472 structures may cause parsing errors.
476 The use of multiple B<-signer> options and the B<-resign> command were first
477 added in OpenSSL 1.0.0
479 The -no_alt_chains options was first added to OpenSSL 1.1.0.