25 [B<-attime timestamp>]
46 [B<-verify_depth num>]
47 [B<-verify_email email>]
48 [B<-verify_hostname hostname>]
50 [B<-verify_name name>]
55 [B<-inform SMIME|PEM|DER>]
59 [B<-outform SMIME|PEM|DER>]
74 The B<smime> command handles S/MIME mail. It can encrypt, decrypt, sign and
75 verify S/MIME messages.
77 =head1 COMMAND OPTIONS
79 There are six operation options that set the type of operation to be performed.
80 The meaning of the other options varies according to the operation type.
86 Print out a usage message.
90 encrypt mail for the given recipient certificates. Input file is the message
91 to be encrypted. The output file is the encrypted mail in MIME format.
93 Note that no revocation check is done for the recipient cert, so if that
94 key has been compromised, others may be able to decrypt the text.
98 decrypt mail using the supplied certificate and private key. Expects an
99 encrypted mail message in MIME format for the input file. The decrypted mail
100 is written to the output file.
104 sign mail using the supplied certificate and private key. Input file is
105 the message to be signed. The signed message in MIME format is written
110 verify signed mail. Expects a signed mail message on input and outputs
111 the signed data. Both clear text and opaque signing is supported.
115 takes an input message and writes out a PEM encoded PKCS#7 structure.
119 resign a message: take an existing message and one or more new signers.
121 =item B<-in filename>
123 the input message to be encrypted or signed or the MIME message to
124 be decrypted or verified.
126 =item B<-inform SMIME|PEM|DER>
128 this specifies the input format for the PKCS#7 structure. The default
129 is B<SMIME> which reads an S/MIME format message. B<PEM> and B<DER>
130 format change this to expect PEM and DER format PKCS#7 structures
131 instead. This currently only affects the input format of the PKCS#7
132 structure, if no PKCS#7 structure is being input (for example with
133 B<-encrypt> or B<-sign>) this option has no effect.
135 =item B<-out filename>
137 the message text that has been decrypted or verified or the output MIME
138 format message that has been signed or verified.
140 =item B<-outform SMIME|PEM|DER>
142 this specifies the output format for the PKCS#7 structure. The default
143 is B<SMIME> which write an S/MIME format message. B<PEM> and B<DER>
144 format change this to write PEM and DER format PKCS#7 structures
145 instead. This currently only affects the output format of the PKCS#7
146 structure, if no PKCS#7 structure is being output (for example with
147 B<-verify> or B<-decrypt>) this option has no effect.
149 =item B<-stream -indef -noindef>
151 the B<-stream> and B<-indef> options are equivalent and enable streaming I/O
152 for encoding operations. This permits single pass processing of data without
153 the need to hold the entire contents in memory, potentially supporting very
154 large files. Streaming is automatically set for S/MIME signing with detached
155 data if the output format is B<SMIME> it is currently off by default for all
160 disable streaming I/O where it would produce and indefinite length constructed
161 encoding. This option currently has no effect. In future streaming will be
162 enabled by default on all relevant operations and this option will disable it.
164 =item B<-content filename>
166 This specifies a file containing the detached content, this is only
167 useful with the B<-verify> command. This is only usable if the PKCS#7
168 structure is using the detached signature form where the content is
169 not included. This option will override any content if the input format
170 is S/MIME and it uses the multipart/signed MIME content type.
174 this option adds plain text (text/plain) MIME headers to the supplied
175 message if encrypting or signing. If decrypting or verifying it strips
176 off text headers: if the decrypted or verified message is not of MIME
177 type text/plain then an error occurs.
179 =item B<-CAfile file>
181 a file containing trusted CA certificates, only used with B<-verify>.
185 a directory containing trusted CA certificates, only used with
186 B<-verify>. This directory must be a standard certificate directory: that
187 is a hash of each subject name (using B<x509 -hash>) should be linked
192 Do not load the trusted CA certificates from the default file location
196 Do not load the trusted CA certificates from the default directory location
200 digest algorithm to use when signing or resigning. If not present then the
201 default digest algorithm for the signing key will be used (usually SHA1).
205 the encryption algorithm to use. For example DES (56 bits) - B<-des>,
206 triple DES (168 bits) - B<-des3>,
207 EVP_get_cipherbyname() function) can also be used preceded by a dash, for
208 example B<-aes-128-cbc>. See L<B<enc>|enc(1)> for list of ciphers
209 supported by your version of OpenSSL.
211 If not specified triple DES is used. Only used with B<-encrypt>.
215 when verifying a message normally certificates (if any) included in
216 the message are searched for the signing certificate. With this option
217 only the certificates specified in the B<-certfile> option are used.
218 The supplied certificates can still be used as untrusted CAs however.
222 do not verify the signers certificate of a signed message.
226 do not do chain verification of signers certificates: that is don't
227 use the certificates in the signed message as untrusted CAs.
231 don't try to verify the signatures on the message.
235 when signing a message the signer's certificate is normally included
236 with this option it is excluded. This will reduce the size of the
237 signed message but the verifier must have a copy of the signers certificate
238 available locally (passed using the B<-certfile> option for example).
242 normally when a message is signed a set of attributes are included which
243 include the signing time and supported symmetric algorithms. With this
244 option they are not included.
248 normally the input message is converted to "canonical" format which is
249 effectively using CR and LF as end of line: as required by the S/MIME
250 specification. When this option is present no translation occurs. This
251 is useful when handling binary data which may not be in MIME format.
255 normally the output file uses a single B<LF> as end of line. When this
256 option is present B<CRLF> is used instead.
260 when signing a message use opaque signing: this form is more resistant
261 to translation by mail relays but it cannot be read by mail agents that
262 do not support S/MIME. Without this option cleartext signing with
263 the MIME type multipart/signed is used.
265 =item B<-certfile file>
267 allows additional certificates to be specified. When signing these will
268 be included with the message. When verifying these will be searched for
269 the signers certificates. The certificates should be in PEM format.
271 =item B<-signer file>
273 a signing certificate when signing or resigning a message, this option can be
274 used multiple times if more than one signer is required. If a message is being
275 verified then the signers certificates will be written to this file if the
276 verification was successful.
280 the recipients certificate when decrypting a message. This certificate
281 must match one of the recipients of the message or an error occurs.
285 the private key to use when signing or decrypting. This must match the
286 corresponding certificate. If this option is not specified then the
287 private key must be included in the certificate file specified with
288 the B<-recip> or B<-signer> file. When signing this option can be used
289 multiple times to specify successive keys.
293 the private key password source. For more information about the format of B<arg>
294 see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)>.
296 =item B<-rand file(s)>
298 a file or files containing random data used to seed the random number
299 generator, or an EGD socket (see L<RAND_egd(3)>).
300 Multiple files can be specified separated by an OS-dependent character.
301 The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for
306 one or more certificates of message recipients: used when encrypting
309 =item B<-to, -from, -subject>
311 the relevant mail headers. These are included outside the signed
312 portion of a message so they may be included manually. If signing
313 then many S/MIME mail clients check the signers certificate's email
314 address matches that specified in the From: address.
316 =item B<-attime>, B<-check_ss_sig>, B<-crl_check>, B<-crl_check_all>,
317 B<-explicit_policy>, B<-extended_crl>, B<-ignore_critical>, B<-inhibit_any>,
318 B<-inhibit_map>, B<-no_alt_chains>, B<-partial_chain>, B<-policy>,
319 B<-policy_check>, B<-policy_print>, B<-purpose>, B<-suiteB_128>,
320 B<-suiteB_128_only>, B<-suiteB_192>, B<-trusted_first>, B<-use_deltas>,
321 B<-auth_level>, B<-verify_depth>, B<-verify_email>, B<-verify_hostname>,
322 B<-verify_ip>, B<-verify_name>, B<-x509_strict>
324 Set various options of certificate chain verification. See
325 L<verify(1)> manual page for details.
331 The MIME message must be sent without any blank lines between the
332 headers and the output. Some mail programs will automatically add
333 a blank line. Piping the mail directly to sendmail is one way to
334 achieve the correct format.
336 The supplied message to be signed or encrypted must include the
337 necessary MIME headers or many S/MIME clients won't display it
338 properly (if at all). You can use the B<-text> option to automatically
339 add plain text headers.
341 A "signed and encrypted" message is one where a signed message is
342 then encrypted. This can be produced by encrypting an already signed
343 message: see the examples section.
345 This version of the program only allows one signer per message but it
346 will verify multiple signers on received messages. Some S/MIME clients
347 choke if a message contains multiple signers. It is possible to sign
348 messages "in parallel" by signing an already signed message.
350 The options B<-encrypt> and B<-decrypt> reflect common usage in S/MIME
351 clients. Strictly speaking these process PKCS#7 enveloped data: PKCS#7
352 encrypted data is used for other purposes.
354 The B<-resign> option uses an existing message digest when adding a new
355 signer. This means that attributes must be present in at least one existing
356 signer using the same message digest or this operation will fail.
358 The B<-stream> and B<-indef> options enable streaming I/O support.
359 As a result the encoding is BER using indefinite length constructed encoding
360 and no longer DER. Streaming is supported for the B<-encrypt> operation and the
361 B<-sign> operation if the content is not detached.
363 Streaming is always used for the B<-sign> operation with detached data but
364 since the content is no longer part of the PKCS#7 structure the encoding
373 the operation was completely successfully.
377 an error occurred parsing the command options.
381 one of the input files could not be read.
385 an error occurred creating the PKCS#7 file or when reading the MIME
390 an error occurred decrypting or verifying the message.
394 the message was verified correctly but an error occurred writing out
395 the signers certificates.
401 Create a cleartext signed message:
403 openssl smime -sign -in message.txt -text -out mail.msg \
406 Create an opaque signed message:
408 openssl smime -sign -in message.txt -text -out mail.msg -nodetach \
411 Create a signed message, include some additional certificates and
412 read the private key from another file:
414 openssl smime -sign -in in.txt -text -out mail.msg \
415 -signer mycert.pem -inkey mykey.pem -certfile mycerts.pem
417 Create a signed message with two signers:
419 openssl smime -sign -in message.txt -text -out mail.msg \
420 -signer mycert.pem -signer othercert.pem
422 Send a signed message under Unix directly to sendmail, including headers:
424 openssl smime -sign -in in.txt -text -signer mycert.pem \
425 -from steve@openssl.org -to someone@somewhere \
426 -subject "Signed message" | sendmail someone@somewhere
428 Verify a message and extract the signer's certificate if successful:
430 openssl smime -verify -in mail.msg -signer user.pem -out signedtext.txt
432 Send encrypted mail using triple DES:
434 openssl smime -encrypt -in in.txt -from steve@openssl.org \
435 -to someone@somewhere -subject "Encrypted message" \
436 -des3 user.pem -out mail.msg
438 Sign and encrypt mail:
440 openssl smime -sign -in ml.txt -signer my.pem -text \
441 | openssl smime -encrypt -out mail.msg \
442 -from steve@openssl.org -to someone@somewhere \
443 -subject "Signed and Encrypted message" -des3 user.pem
445 Note: the encryption command does not include the B<-text> option because the
446 message being encrypted already has MIME headers.
450 openssl smime -decrypt -in mail.msg -recip mycert.pem -inkey key.pem
452 The output from Netscape form signing is a PKCS#7 structure with the
453 detached signature format. You can use this program to verify the
454 signature by line wrapping the base64 encoded structure and surrounding
457 -----BEGIN PKCS7-----
460 and using the command:
462 openssl smime -verify -inform PEM -in signature.pem -content content.txt
464 Alternatively you can base64 decode the signature and use:
466 openssl smime -verify -inform DER -in signature.der -content content.txt
468 Create an encrypted message using 128 bit Camellia:
470 openssl smime -encrypt -in plain.txt -camellia128 -out mail.msg cert.pem
472 Add a signer to an existing message:
474 openssl smime -resign -in mail.msg -signer newsign.pem -out mail2.msg
478 The MIME parser isn't very clever: it seems to handle most messages that I've
479 thrown at it but it may choke on others.
481 The code currently will only write out the signer's certificate to a file: if
482 the signer has a separate encryption certificate this must be manually
483 extracted. There should be some heuristic that determines the correct
484 encryption certificate.
486 Ideally a database should be maintained of a certificates for each email
489 The code doesn't currently take note of the permitted symmetric encryption
490 algorithms as supplied in the SMIMECapabilities signed attribute. This means the
491 user has to manually include the correct encryption algorithm. It should store
492 the list of permitted ciphers in a database and only use those.
494 No revocation checking is done on the signer's certificate.
496 The current code can only handle S/MIME v2 messages, the more complex S/MIME v3
497 structures may cause parsing errors.
501 The use of multiple B<-signer> options and the B<-resign> command were first
502 added in OpenSSL 1.0.0
504 The -no_alt_chains options was first added to OpenSSL 1.1.0.
508 Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.
510 Licensed under the OpenSSL license (the "License"). You may not use
511 this file except in compliance with the License. You can obtain a copy
512 in the file LICENSE in the source distribution or at
513 L<https://www.openssl.org/source/license.html>.