22 [B<-attime timestamp>]
43 [B<-verify_depth num>]
44 [B<-verify_email email>]
45 [B<-verify_hostname hostname>]
47 [B<-verify_name name>]
52 [B<-inform SMIME|PEM|DER>]
56 [B<-outform SMIME|PEM|DER>]
71 The B<smime> command handles S/MIME mail. It can encrypt, decrypt, sign and
72 verify S/MIME messages.
74 =head1 COMMAND OPTIONS
76 There are six operation options that set the type of operation to be performed.
77 The meaning of the other options varies according to the operation type.
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.
88 decrypt mail using the supplied certificate and private key. Expects an
89 encrypted mail message in MIME format for the input file. The decrypted mail
90 is written to the output file.
94 sign mail using the supplied certificate and private key. Input file is
95 the message to be signed. The signed message in MIME format is written
100 verify signed mail. Expects a signed mail message on input and outputs
101 the signed data. Both clear text and opaque signing is supported.
105 takes an input message and writes out a PEM encoded PKCS#7 structure.
109 resign a message: take an existing message and one or more new signers.
111 =item B<-in filename>
113 the input message to be encrypted or signed or the MIME message to
114 be decrypted or verified.
116 =item B<-inform SMIME|PEM|DER>
118 this specifies the input format for the PKCS#7 structure. The default
119 is B<SMIME> which reads an S/MIME format message. B<PEM> and B<DER>
120 format change this to expect PEM and DER format PKCS#7 structures
121 instead. This currently only affects the input format of the PKCS#7
122 structure, if no PKCS#7 structure is being input (for example with
123 B<-encrypt> or B<-sign>) this option has no effect.
125 =item B<-out filename>
127 the message text that has been decrypted or verified or the output MIME
128 format message that has been signed or verified.
130 =item B<-outform SMIME|PEM|DER>
132 this specifies the output format for the PKCS#7 structure. The default
133 is B<SMIME> which write an S/MIME format message. B<PEM> and B<DER>
134 format change this to write PEM and DER format PKCS#7 structures
135 instead. This currently only affects the output format of the PKCS#7
136 structure, if no PKCS#7 structure is being output (for example with
137 B<-verify> or B<-decrypt>) this option has no effect.
139 =item B<-stream -indef -noindef>
141 the B<-stream> and B<-indef> options are equivalent and enable streaming I/O
142 for encoding operations. This permits single pass processing of data without
143 the need to hold the entire contents in memory, potentially supporting very
144 large files. Streaming is automatically set for S/MIME signing with detached
145 data if the output format is B<SMIME> it is currently off by default for all
150 disable streaming I/O where it would produce and indefinite length constructed
151 encoding. This option currently has no effect. In future streaming will be
152 enabled by default on all relevant operations and this option will disable it.
154 =item B<-content filename>
156 This specifies a file containing the detached content, this is only
157 useful with the B<-verify> command. This is only usable if the PKCS#7
158 structure is using the detached signature form where the content is
159 not included. This option will override any content if the input format
160 is S/MIME and it uses the multipart/signed MIME content type.
164 this option adds plain text (text/plain) MIME headers to the supplied
165 message if encrypting or signing. If decrypting or verifying it strips
166 off text headers: if the decrypted or verified message is not of MIME
167 type text/plain then an error occurs.
169 =item B<-CAfile file>
171 a file containing trusted CA certificates, only used with B<-verify>.
175 a directory containing trusted CA certificates, only used with
176 B<-verify>. This directory must be a standard certificate directory: that
177 is a hash of each subject name (using B<x509 -hash>) should be linked
182 Do not load the trusted CA certificates from the default file location
186 Do not load the trusted CA certificates from the default directory location
190 digest algorithm to use when signing or resigning. If not present then the
191 default digest algorithm for the signing key will be used (usually SHA1).
195 the encryption algorithm to use. For example DES (56 bits) - B<-des>,
196 triple DES (168 bits) - B<-des3>,
197 EVP_get_cipherbyname() function) can also be used preceded by a dash, for
198 example B<-aes_128_cbc>. See L<B<enc>|enc(1)> for list of ciphers
199 supported by your version of OpenSSL.
201 If not specified triple DES is used. Only used with B<-encrypt>.
205 when verifying a message normally certificates (if any) included in
206 the message are searched for the signing certificate. With this option
207 only the certificates specified in the B<-certfile> option are used.
208 The supplied certificates can still be used as untrusted CAs however.
212 do not verify the signers certificate of a signed message.
216 do not do chain verification of signers certificates: that is don't
217 use the certificates in the signed message as untrusted CAs.
221 don't try to verify the signatures on the message.
225 when signing a message the signer's certificate is normally included
226 with this option it is excluded. This will reduce the size of the
227 signed message but the verifier must have a copy of the signers certificate
228 available locally (passed using the B<-certfile> option for example).
232 normally when a message is signed a set of attributes are included which
233 include the signing time and supported symmetric algorithms. With this
234 option they are not included.
238 normally the input message is converted to "canonical" format which is
239 effectively using CR and LF as end of line: as required by the S/MIME
240 specification. When this option is present no translation occurs. This
241 is useful when handling binary data which may not be in MIME format.
245 when signing a message use opaque signing: this form is more resistant
246 to translation by mail relays but it cannot be read by mail agents that
247 do not support S/MIME. Without this option cleartext signing with
248 the MIME type multipart/signed is used.
250 =item B<-certfile file>
252 allows additional certificates to be specified. When signing these will
253 be included with the message. When verifying these will be searched for
254 the signers certificates. The certificates should be in PEM format.
256 =item B<-signer file>
258 a signing certificate when signing or resigning a message, this option can be
259 used multiple times if more than one signer is required. If a message is being
260 verified then the signers certificates will be written to this file if the
261 verification was successful.
265 the recipients certificate when decrypting a message. This certificate
266 must match one of the recipients of the message or an error occurs.
270 the private key to use when signing or decrypting. This must match the
271 corresponding certificate. If this option is not specified then the
272 private key must be included in the certificate file specified with
273 the B<-recip> or B<-signer> file. When signing this option can be used
274 multiple times to specify successive keys.
278 the private key password source. For more information about the format of B<arg>
279 see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)>.
281 =item B<-rand file(s)>
283 a file or files containing random data used to seed the random number
284 generator, or an EGD socket (see L<RAND_egd(3)>).
285 Multiple files can be specified separated by a OS-dependent character.
286 The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for
291 one or more certificates of message recipients: used when encrypting
294 =item B<-to, -from, -subject>
296 the relevant mail headers. These are included outside the signed
297 portion of a message so they may be included manually. If signing
298 then many S/MIME mail clients check the signers certificate's email
299 address matches that specified in the From: address.
301 =item B<-attime>, B<-check_ss_sig>, B<-crl_check>, B<-crl_check_all>,
302 B<explicit_policy>, B<-extended_crl>, B<-ignore_critical>, B<-inhibit_any>,
303 B<-inhibit_map>, B<-issuer_checks>, B<-partial_chain>, B<-policy>,
304 B<-policy_check>, B<-policy_print>, B<-purpose>, B<-suiteB_128>,
305 B<-suiteB_128_only>, B<-suiteB_192>, B<-trusted_first>, B<-no_alt_chains>,
306 B<-use_deltas>, B<-verify_depth>, B<-verify_email>, B<-verify_hostname>,
307 B<-verify_ip>, B<-verify_name>, B<-x509_strict>
309 Set various options of certificate chain verification. See
310 L<verify(1)> manual page for details.
316 The MIME message must be sent without any blank lines between the
317 headers and the output. Some mail programs will automatically add
318 a blank line. Piping the mail directly to sendmail is one way to
319 achieve the correct format.
321 The supplied message to be signed or encrypted must include the
322 necessary MIME headers or many S/MIME clients wont display it
323 properly (if at all). You can use the B<-text> option to automatically
324 add plain text headers.
326 A "signed and encrypted" message is one where a signed message is
327 then encrypted. This can be produced by encrypting an already signed
328 message: see the examples section.
330 This version of the program only allows one signer per message but it
331 will verify multiple signers on received messages. Some S/MIME clients
332 choke if a message contains multiple signers. It is possible to sign
333 messages "in parallel" by signing an already signed message.
335 The options B<-encrypt> and B<-decrypt> reflect common usage in S/MIME
336 clients. Strictly speaking these process PKCS#7 enveloped data: PKCS#7
337 encrypted data is used for other purposes.
339 The B<-resign> option uses an existing message digest when adding a new
340 signer. This means that attributes must be present in at least one existing
341 signer using the same message digest or this operation will fail.
343 The B<-stream> and B<-indef> options enable experimental streaming I/O support.
344 As a result the encoding is BER using indefinite length constructed encoding
345 and no longer DER. Streaming is supported for the B<-encrypt> operation and the
346 B<-sign> operation if the content is not detached.
348 Streaming is always used for the B<-sign> operation with detached data but
349 since the content is no longer part of the PKCS#7 structure the encoding
358 the operation was completely successfully.
362 an error occurred parsing the command options.
366 one of the input files could not be read.
370 an error occurred creating the PKCS#7 file or when reading the MIME
375 an error occurred decrypting or verifying the message.
379 the message was verified correctly but an error occurred writing out
380 the signers certificates.
386 Create a cleartext signed message:
388 openssl smime -sign -in message.txt -text -out mail.msg \
391 Create an opaque signed message:
393 openssl smime -sign -in message.txt -text -out mail.msg -nodetach \
396 Create a signed message, include some additional certificates and
397 read the private key from another file:
399 openssl smime -sign -in in.txt -text -out mail.msg \
400 -signer mycert.pem -inkey mykey.pem -certfile mycerts.pem
402 Create a signed message with two signers:
404 openssl smime -sign -in message.txt -text -out mail.msg \
405 -signer mycert.pem -signer othercert.pem
407 Send a signed message under Unix directly to sendmail, including headers:
409 openssl smime -sign -in in.txt -text -signer mycert.pem \
410 -from steve@openssl.org -to someone@somewhere \
411 -subject "Signed message" | sendmail someone@somewhere
413 Verify a message and extract the signer's certificate if successful:
415 openssl smime -verify -in mail.msg -signer user.pem -out signedtext.txt
417 Send encrypted mail using triple DES:
419 openssl smime -encrypt -in in.txt -from steve@openssl.org \
420 -to someone@somewhere -subject "Encrypted message" \
421 -des3 user.pem -out mail.msg
423 Sign and encrypt mail:
425 openssl smime -sign -in ml.txt -signer my.pem -text \
426 | openssl smime -encrypt -out mail.msg \
427 -from steve@openssl.org -to someone@somewhere \
428 -subject "Signed and Encrypted message" -des3 user.pem
430 Note: the encryption command does not include the B<-text> option because the
431 message being encrypted already has MIME headers.
435 openssl smime -decrypt -in mail.msg -recip mycert.pem -inkey key.pem
437 The output from Netscape form signing is a PKCS#7 structure with the
438 detached signature format. You can use this program to verify the
439 signature by line wrapping the base64 encoded structure and surrounding
442 -----BEGIN PKCS7-----
445 and using the command:
447 openssl smime -verify -inform PEM -in signature.pem -content content.txt
449 Alternatively you can base64 decode the signature and use:
451 openssl smime -verify -inform DER -in signature.der -content content.txt
453 Create an encrypted message using 128 bit Camellia:
455 openssl smime -encrypt -in plain.txt -camellia128 -out mail.msg cert.pem
457 Add a signer to an existing message:
459 openssl smime -resign -in mail.msg -signer newsign.pem -out mail2.msg
463 The MIME parser isn't very clever: it seems to handle most messages that I've
464 thrown at it but it may choke on others.
466 The code currently will only write out the signer's certificate to a file: if
467 the signer has a separate encryption certificate this must be manually
468 extracted. There should be some heuristic that determines the correct
469 encryption certificate.
471 Ideally a database should be maintained of a certificates for each email
474 The code doesn't currently take note of the permitted symmetric encryption
475 algorithms as supplied in the SMIMECapabilities signed attribute. This means the
476 user has to manually include the correct encryption algorithm. It should store
477 the list of permitted ciphers in a database and only use those.
479 No revocation checking is done on the signer's certificate.
481 The current code can only handle S/MIME v2 messages, the more complex S/MIME v3
482 structures may cause parsing errors.
486 The use of multiple B<-signer> options and the B<-resign> command were first
487 added in OpenSSL 1.0.0
489 The -no_alt_chains options was first added to OpenSSL 1.1.0.