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>]
57 [B<-inkey file_or_id>]
59 [B<-outform SMIME|PEM|DER>]
75 The B<smime> command handles S/MIME mail. It can encrypt, decrypt, sign and
76 verify S/MIME messages.
80 There are six operation options that set the type of operation to be performed.
81 The meaning of the other options varies according to the operation type.
87 Print out a usage message.
91 Encrypt mail for the given recipient certificates. Input file is the message
92 to be encrypted. The output file is the encrypted mail in MIME format.
94 Note that no revocation check is done for the recipient cert, so if that
95 key has been compromised, others may be able to decrypt the text.
99 Decrypt mail using the supplied certificate and private key. Expects an
100 encrypted mail message in MIME format for the input file. The decrypted mail
101 is written to the output file.
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 PKCS#7 structure.
120 Resign a message: take an existing message and one or more new signers.
122 =item B<-in filename>
124 The input message to be encrypted or signed or the MIME message to
125 be decrypted or verified.
127 =item B<-inform SMIME|PEM|DER>
129 This specifies the input format for the PKCS#7 structure. The default
130 is B<SMIME> which reads an S/MIME format message. B<PEM> and B<DER>
131 format change this to expect PEM and DER format PKCS#7 structures
132 instead. This currently only affects the input format of the PKCS#7
133 structure, if no PKCS#7 structure is being input (for example with
134 B<-encrypt> or B<-sign>) this option has no effect.
136 =item B<-out filename>
138 The message text that has been decrypted or verified or the output MIME
139 format message that has been signed or verified.
141 =item B<-outform SMIME|PEM|DER>
143 This specifies the output format for the PKCS#7 structure. The default
144 is B<SMIME> which write an S/MIME format message. B<PEM> and B<DER>
145 format change this to write PEM and DER format PKCS#7 structures
146 instead. This currently only affects the output format of the PKCS#7
147 structure, if no PKCS#7 structure is being output (for example with
148 B<-verify> or B<-decrypt>) this option has no effect.
150 =item B<-stream -indef -noindef>
152 The B<-stream> and B<-indef> options are equivalent and enable streaming I/O
153 for encoding operations. This permits single pass processing of data without
154 the need to hold the entire contents in memory, potentially supporting very
155 large files. Streaming is automatically set for S/MIME signing with detached
156 data if the output format is B<SMIME> it is currently off by default for all
161 Disable streaming I/O where it would produce and indefinite length constructed
162 encoding. This option currently has no effect. In future streaming will be
163 enabled by default on all relevant operations and this option will disable it.
165 =item B<-content filename>
167 This specifies a file containing the detached content, this is only
168 useful with the B<-verify> command. This is only usable if the PKCS#7
169 structure is using the detached signature form where the content is
170 not included. This option will override any content if the input format
171 is S/MIME and it uses the multipart/signed MIME content type.
175 This option adds plain text (text/plain) MIME headers to the supplied
176 message if encrypting or signing. If decrypting or verifying it strips
177 off text headers: if the decrypted or verified message is not of MIME
178 type text/plain then an error occurs.
180 =item B<-CAfile file>
182 A file containing trusted CA certificates, only used with B<-verify>.
186 A directory containing trusted CA certificates, only used with
187 B<-verify>. This directory must be a standard certificate directory: that
188 is a hash of each subject name (using B<x509 -hash>) should be linked
193 Do not load the trusted CA certificates from the default file location.
197 Do not load the trusted CA certificates from the default directory location.
201 Digest algorithm to use when signing or resigning. If not present then the
202 default digest algorithm for the signing key will be used (usually SHA1).
206 The encryption algorithm to use. For example DES (56 bits) - B<-des>,
207 triple DES (168 bits) - B<-des3>,
208 EVP_get_cipherbyname() function) can also be used preceded by a dash, for
209 example B<-aes-128-cbc>. See L<B<enc>|enc(1)> for list of ciphers
210 supported by your version of OpenSSL.
212 If not specified triple DES is used. Only used with B<-encrypt>.
216 When verifying a message normally certificates (if any) included in
217 the message are searched for the signing certificate. With this option
218 only the certificates specified in the B<-certfile> option are used.
219 The supplied certificates can still be used as untrusted CAs however.
223 Do not verify the signers certificate of a signed message.
227 Do not do chain verification of signers certificates: that is don't
228 use the certificates in the signed message as untrusted CAs.
232 Don't try to verify the signatures on the message.
236 When signing a message the signer's certificate is normally included
237 with this option it is excluded. This will reduce the size of the
238 signed message but the verifier must have a copy of the signers certificate
239 available locally (passed using the B<-certfile> option for example).
243 Normally when a message is signed a set of attributes are included which
244 include the signing time and supported symmetric algorithms. With this
245 option they are not included.
249 Normally the input message is converted to "canonical" format which is
250 effectively using CR and LF as end of line: as required by the S/MIME
251 specification. When this option is present no translation occurs. This
252 is useful when handling binary data which may not be in MIME format.
256 Normally the output file uses a single B<LF> as end of line. When this
257 option is present B<CRLF> is used instead.
261 When signing a message use opaque signing: this form is more resistant
262 to translation by mail relays but it cannot be read by mail agents that
263 do not support S/MIME. Without this option cleartext signing with
264 the MIME type multipart/signed is used.
266 =item B<-certfile file>
268 Allows additional certificates to be specified. When signing these will
269 be included with the message. When verifying these will be searched for
270 the signers certificates. The certificates should be in PEM format.
272 =item B<-signer file>
274 A signing certificate when signing or resigning a message, this option can be
275 used multiple times if more than one signer is required. If a message is being
276 verified then the signers certificates will be written to this file if the
277 verification was successful.
281 The recipients certificate when decrypting a message. This certificate
282 must match one of the recipients of the message or an error occurs.
284 =item B<-inkey file_or_id>
286 The private key to use when signing or decrypting. This must match the
287 corresponding certificate. If this option is not specified then the
288 private key must be included in the certificate file specified with
289 the B<-recip> or B<-signer> file. When signing this option can be used
290 multiple times to specify successive keys.
291 If no engine is used, the argument is taken as a file; if an engine is
292 specified, the argument is given to the engine as a key identifier.
296 The private key password source. For more information about the format of B<arg>
297 see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)>.
299 =item B<-rand file...>
301 A file or files containing random data used to seed the random number
303 Multiple files can be specified separated by an OS-dependent character.
304 The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for
307 =item [B<-writerand file>]
309 Writes random data to the specified I<file> upon exit.
310 This can be used with a subsequent B<-rand> flag.
314 One or more certificates of message recipients: used when encrypting
317 =item B<-to, -from, -subject>
319 The relevant mail headers. These are included outside the signed
320 portion of a message so they may be included manually. If signing
321 then many S/MIME mail clients check the signers certificate's email
322 address matches that specified in the From: address.
324 =item B<-attime>, B<-check_ss_sig>, B<-crl_check>, B<-crl_check_all>,
325 B<-explicit_policy>, B<-extended_crl>, B<-ignore_critical>, B<-inhibit_any>,
326 B<-inhibit_map>, B<-no_alt_chains>, B<-partial_chain>, B<-policy>,
327 B<-policy_check>, B<-policy_print>, B<-purpose>, B<-suiteB_128>,
328 B<-suiteB_128_only>, B<-suiteB_192>, B<-trusted_first>, B<-use_deltas>,
329 B<-auth_level>, B<-verify_depth>, B<-verify_email>, B<-verify_hostname>,
330 B<-verify_ip>, B<-verify_name>, B<-x509_strict>
332 Set various options of certificate chain verification. See
333 L<verify(1)> manual page for details.
339 The MIME message must be sent without any blank lines between the
340 headers and the output. Some mail programs will automatically add
341 a blank line. Piping the mail directly to sendmail is one way to
342 achieve the correct format.
344 The supplied message to be signed or encrypted must include the
345 necessary MIME headers or many S/MIME clients won't display it
346 properly (if at all). You can use the B<-text> option to automatically
347 add plain text headers.
349 A "signed and encrypted" message is one where a signed message is
350 then encrypted. This can be produced by encrypting an already signed
351 message: see the examples section.
353 This version of the program only allows one signer per message but it
354 will verify multiple signers on received messages. Some S/MIME clients
355 choke if a message contains multiple signers. It is possible to sign
356 messages "in parallel" by signing an already signed message.
358 The options B<-encrypt> and B<-decrypt> reflect common usage in S/MIME
359 clients. Strictly speaking these process PKCS#7 enveloped data: PKCS#7
360 encrypted data is used for other purposes.
362 The B<-resign> option uses an existing message digest when adding a new
363 signer. This means that attributes must be present in at least one existing
364 signer using the same message digest or this operation will fail.
366 The B<-stream> and B<-indef> options enable streaming I/O support.
367 As a result the encoding is BER using indefinite length constructed encoding
368 and no longer DER. Streaming is supported for the B<-encrypt> operation and the
369 B<-sign> operation if the content is not detached.
371 Streaming is always used for the B<-sign> operation with detached data but
372 since the content is no longer part of the PKCS#7 structure the encoding
381 The operation was completely successfully.
385 An error occurred parsing the command options.
389 One of the input files could not be read.
393 An error occurred creating the PKCS#7 file or when reading the MIME
398 An error occurred decrypting or verifying the message.
402 The message was verified correctly but an error occurred writing out
403 the signers certificates.
409 Create a cleartext signed message:
411 openssl smime -sign -in message.txt -text -out mail.msg \
414 Create an opaque signed message:
416 openssl smime -sign -in message.txt -text -out mail.msg -nodetach \
419 Create a signed message, include some additional certificates and
420 read the private key from another file:
422 openssl smime -sign -in in.txt -text -out mail.msg \
423 -signer mycert.pem -inkey mykey.pem -certfile mycerts.pem
425 Create a signed message with two signers:
427 openssl smime -sign -in message.txt -text -out mail.msg \
428 -signer mycert.pem -signer othercert.pem
430 Send a signed message under Unix directly to sendmail, including headers:
432 openssl smime -sign -in in.txt -text -signer mycert.pem \
433 -from steve@openssl.org -to someone@somewhere \
434 -subject "Signed message" | sendmail someone@somewhere
436 Verify a message and extract the signer's certificate if successful:
438 openssl smime -verify -in mail.msg -signer user.pem -out signedtext.txt
440 Send encrypted mail using triple DES:
442 openssl smime -encrypt -in in.txt -from steve@openssl.org \
443 -to someone@somewhere -subject "Encrypted message" \
444 -des3 user.pem -out mail.msg
446 Sign and encrypt mail:
448 openssl smime -sign -in ml.txt -signer my.pem -text \
449 | openssl smime -encrypt -out mail.msg \
450 -from steve@openssl.org -to someone@somewhere \
451 -subject "Signed and Encrypted message" -des3 user.pem
453 Note: the encryption command does not include the B<-text> option because the
454 message being encrypted already has MIME headers.
458 openssl smime -decrypt -in mail.msg -recip mycert.pem -inkey key.pem
460 The output from Netscape form signing is a PKCS#7 structure with the
461 detached signature format. You can use this program to verify the
462 signature by line wrapping the base64 encoded structure and surrounding
465 -----BEGIN PKCS7-----
468 and using the command:
470 openssl smime -verify -inform PEM -in signature.pem -content content.txt
472 Alternatively you can base64 decode the signature and use:
474 openssl smime -verify -inform DER -in signature.der -content content.txt
476 Create an encrypted message using 128 bit Camellia:
478 openssl smime -encrypt -in plain.txt -camellia128 -out mail.msg cert.pem
480 Add a signer to an existing message:
482 openssl smime -resign -in mail.msg -signer newsign.pem -out mail2.msg
486 The MIME parser isn't very clever: it seems to handle most messages that I've
487 thrown at it but it may choke on others.
489 The code currently will only write out the signer's certificate to a file: if
490 the signer has a separate encryption certificate this must be manually
491 extracted. There should be some heuristic that determines the correct
492 encryption certificate.
494 Ideally a database should be maintained of a certificates for each email
497 The code doesn't currently take note of the permitted symmetric encryption
498 algorithms as supplied in the SMIMECapabilities signed attribute. This means the
499 user has to manually include the correct encryption algorithm. It should store
500 the list of permitted ciphers in a database and only use those.
502 No revocation checking is done on the signer's certificate.
504 The current code can only handle S/MIME v2 messages, the more complex S/MIME v3
505 structures may cause parsing errors.
509 The use of multiple B<-signer> options and the B<-resign> command were first
510 added in OpenSSL 1.0.0
512 The -no_alt_chains options was first added to OpenSSL 1.1.0.
516 Copyright 2000-2017 The OpenSSL Project Authors. All Rights Reserved.
518 Licensed under the OpenSSL license (the "License"). You may not use
519 this file except in compliance with the License. You can obtain a copy
520 in the file LICENSE in the source distribution or at
521 L<https://www.openssl.org/source/license.html>.