2 {- OpenSSL::safe::output_do_not_edit_headers(); -}
6 openssl-smime - S/MIME utility
22 [B<-attime> I<timestamp>]
35 [B<-purpose> I<purpose>]
42 [B<-auth_level> I<num>]
43 [B<-verify_depth> I<num>]
44 [B<-verify_email> I<email>]
45 [B<-verify_hostname> I<hostname>]
47 [B<-verify_name> I<name>]
49 [B<-certfile> I<file>]
52 [B<-inform> B<DER>|B<PEM>|B<SMIME>]
53 [B<-outform> B<DER>|B<PEM>|B<SMIME>]
54 [B<-keyform> B<DER>|B<PEM>|B<ENGINE>]
56 [B<-inkey> I<file_or_id>]
67 {- $OpenSSL::safe::opt_trust_synopsis -}
68 {- $OpenSSL::safe::opt_r_synopsis -}
71 =for openssl ifdef engine
75 This command handles S/MIME mail. It can encrypt, decrypt, sign
76 and 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> I<filename>
124 The input message to be encrypted or signed or the MIME message to
125 be decrypted or verified.
127 =item B<-out> I<filename>
129 The message text that has been decrypted or verified or the output MIME
130 format message that has been signed or verified.
132 =item B<-inform> B<DER>|B<PEM>|B<SMIME>
134 The input format of the PKCS#7 (S/MIME) structure (if one is being read);
135 the default is B<SMIME>.
136 See L<openssl(1)/Format Options> for details.
138 =item B<-outform> B<DER>|B<PEM>|B<SMIME>
140 The output format of the PKCS#7 (S/MIME) structure (if one is being written);
141 the default is B<SMIME>.
142 See L<openssl(1)/Format Options> for details.
144 =item B<-keyform> B<DER>|B<PEM>
146 The key format; the default is B<PEM>.
147 See L<openssl(1)/Format Options> for details.
149 =item B<-stream>, B<-indef>, B<-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> I<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<-md> I<digest>
181 Digest algorithm to use when signing or resigning. If not present then the
182 default digest algorithm for the signing key will be used (usually SHA1).
186 The encryption algorithm to use. For example DES (56 bits) - B<-des>,
187 triple DES (168 bits) - B<-des3>,
188 EVP_get_cipherbyname() function) can also be used preceded by a dash, for
189 example B<-aes-128-cbc>. See L<openssl-enc(1)> for list of ciphers
190 supported by your version of OpenSSL.
192 If not specified triple DES is used. Only used with B<-encrypt>.
196 When verifying a message normally certificates (if any) included in
197 the message are searched for the signing certificate. With this option
198 only the certificates specified in the B<-certfile> option are used.
199 The supplied certificates can still be used as untrusted CAs however.
203 Do not verify the signers certificate of a signed message.
207 Do not do chain verification of signers certificates: that is don't
208 use the certificates in the signed message as untrusted CAs.
212 Don't try to verify the signatures on the message.
216 When signing a message the signer's certificate is normally included
217 with this option it is excluded. This will reduce the size of the
218 signed message but the verifier must have a copy of the signers certificate
219 available locally (passed using the B<-certfile> option for example).
223 Normally when a message is signed a set of attributes are included which
224 include the signing time and supported symmetric algorithms. With this
225 option they are not included.
229 Normally the input message is converted to "canonical" format which is
230 effectively using CR and LF as end of line: as required by the S/MIME
231 specification. When this option is present no translation occurs. This
232 is useful when handling binary data which may not be in MIME format.
236 Normally the output file uses a single B<LF> as end of line. When this
237 option is present B<CRLF> is used instead.
241 When signing a message use opaque signing: this form is more resistant
242 to translation by mail relays but it cannot be read by mail agents that
243 do not support S/MIME. Without this option cleartext signing with
244 the MIME type multipart/signed is used.
246 =item B<-certfile> I<file>
248 Allows additional certificates to be specified. When signing these will
249 be included with the message. When verifying these will be searched for
250 the signers certificates. The certificates should be in PEM format.
252 =item B<-signer> I<file>
254 A signing certificate when signing or resigning a message, this option can be
255 used multiple times if more than one signer is required. If a message is being
256 verified then the signers certificates will be written to this file if the
257 verification was successful.
259 =item B<-recip> I<file>
261 The recipients certificate when decrypting a message. This certificate
262 must match one of the recipients of the message or an error occurs.
264 =item B<-inkey> I<file_or_id>
266 The private key to use when signing or decrypting. This must match the
267 corresponding certificate. If this option is not specified then the
268 private key must be included in the certificate file specified with
269 the B<-recip> or B<-signer> file. When signing this option can be used
270 multiple times to specify successive keys.
271 If no engine is used, the argument is taken as a file; if an engine is
272 specified, the argument is given to the engine as a key identifier.
274 =item B<-passin> I<arg>
276 The private key password source. For more information about the format of I<arg>
277 see L<openssl(1)/Pass Phrase Options>.
279 =item B<-to>, B<-from>, B<-subject>
281 The relevant mail headers. These are included outside the signed
282 portion of a message so they may be included manually. If signing
283 then many S/MIME mail clients check the signers certificate's email
284 address matches that specified in the From: address.
286 =item B<-attime>, B<-check_ss_sig>, B<-crl_check>, B<-crl_check_all>,
287 B<-explicit_policy>, B<-extended_crl>, B<-ignore_critical>, B<-inhibit_any>,
288 B<-inhibit_map>, B<-no_alt_chains>, B<-partial_chain>, B<-policy>,
289 B<-policy_check>, B<-policy_print>, B<-purpose>, B<-suiteB_128>,
290 B<-suiteB_128_only>, B<-suiteB_192>, B<-trusted_first>, B<-use_deltas>,
291 B<-auth_level>, B<-verify_depth>, B<-verify_email>, B<-verify_hostname>,
292 B<-verify_ip>, B<-verify_name>, B<-x509_strict>
294 Set various options of certificate chain verification. See
295 L<openssl-verify(1)> manual page for details.
297 {- $OpenSSL::safe::opt_trust_item -}
299 {- $OpenSSL::safe::opt_r_item -}
301 =item I<cert.pem> ...
303 One or more certificates of message recipients, used when encrypting
310 The MIME message must be sent without any blank lines between the
311 headers and the output. Some mail programs will automatically add
312 a blank line. Piping the mail directly to sendmail is one way to
313 achieve the correct format.
315 The supplied message to be signed or encrypted must include the
316 necessary MIME headers or many S/MIME clients won't display it
317 properly (if at all). You can use the B<-text> option to automatically
318 add plain text headers.
320 A "signed and encrypted" message is one where a signed message is
321 then encrypted. This can be produced by encrypting an already signed
322 message: see the examples section.
324 This version of the program only allows one signer per message but it
325 will verify multiple signers on received messages. Some S/MIME clients
326 choke if a message contains multiple signers. It is possible to sign
327 messages "in parallel" by signing an already signed message.
329 The options B<-encrypt> and B<-decrypt> reflect common usage in S/MIME
330 clients. Strictly speaking these process PKCS#7 enveloped data: PKCS#7
331 encrypted data is used for other purposes.
333 The B<-resign> option uses an existing message digest when adding a new
334 signer. This means that attributes must be present in at least one existing
335 signer using the same message digest or this operation will fail.
337 The B<-stream> and B<-indef> options enable streaming I/O support.
338 As a result the encoding is BER using indefinite length constructed encoding
339 and no longer DER. Streaming is supported for the B<-encrypt> operation and the
340 B<-sign> operation if the content is not detached.
342 Streaming is always used for the B<-sign> operation with detached data but
343 since the content is no longer part of the PKCS#7 structure the encoding
352 The operation was completely successfully.
356 An error occurred parsing the command options.
360 One of the input files could not be read.
364 An error occurred creating the PKCS#7 file or when reading the MIME
369 An error occurred decrypting or verifying the message.
373 The message was verified correctly but an error occurred writing out
374 the signers certificates.
380 Create a cleartext signed message:
382 openssl smime -sign -in message.txt -text -out mail.msg \
385 Create an opaque signed message:
387 openssl smime -sign -in message.txt -text -out mail.msg -nodetach \
390 Create a signed message, include some additional certificates and
391 read the private key from another file:
393 openssl smime -sign -in in.txt -text -out mail.msg \
394 -signer mycert.pem -inkey mykey.pem -certfile mycerts.pem
396 Create a signed message with two signers:
398 openssl smime -sign -in message.txt -text -out mail.msg \
399 -signer mycert.pem -signer othercert.pem
401 Send a signed message under Unix directly to sendmail, including headers:
403 openssl smime -sign -in in.txt -text -signer mycert.pem \
404 -from steve@openssl.org -to someone@somewhere \
405 -subject "Signed message" | sendmail someone@somewhere
407 Verify a message and extract the signer's certificate if successful:
409 openssl smime -verify -in mail.msg -signer user.pem -out signedtext.txt
411 Send encrypted mail using triple DES:
413 openssl smime -encrypt -in in.txt -from steve@openssl.org \
414 -to someone@somewhere -subject "Encrypted message" \
415 -des3 user.pem -out mail.msg
417 Sign and encrypt mail:
419 openssl smime -sign -in ml.txt -signer my.pem -text \
420 | openssl smime -encrypt -out mail.msg \
421 -from steve@openssl.org -to someone@somewhere \
422 -subject "Signed and Encrypted message" -des3 user.pem
424 Note: the encryption command does not include the B<-text> option because the
425 message being encrypted already has MIME headers.
429 openssl smime -decrypt -in mail.msg -recip mycert.pem -inkey key.pem
431 The output from Netscape form signing is a PKCS#7 structure with the
432 detached signature format. You can use this program to verify the
433 signature by line wrapping the base64 encoded structure and surrounding
436 -----BEGIN PKCS7-----
439 and using the command:
441 openssl smime -verify -inform PEM -in signature.pem -content content.txt
443 Alternatively you can base64 decode the signature and use:
445 openssl smime -verify -inform DER -in signature.der -content content.txt
447 Create an encrypted message using 128 bit Camellia:
449 openssl smime -encrypt -in plain.txt -camellia128 -out mail.msg cert.pem
451 Add a signer to an existing message:
453 openssl smime -resign -in mail.msg -signer newsign.pem -out mail2.msg
457 The MIME parser isn't very clever: it seems to handle most messages that I've
458 thrown at it but it may choke on others.
460 The code currently will only write out the signer's certificate to a file: if
461 the signer has a separate encryption certificate this must be manually
462 extracted. There should be some heuristic that determines the correct
463 encryption certificate.
465 Ideally a database should be maintained of a certificates for each email
468 The code doesn't currently take note of the permitted symmetric encryption
469 algorithms as supplied in the SMIMECapabilities signed attribute. This means the
470 user has to manually include the correct encryption algorithm. It should store
471 the list of permitted ciphers in a database and only use those.
473 No revocation checking is done on the signer's certificate.
475 The current code can only handle S/MIME v2 messages, the more complex S/MIME v3
476 structures may cause parsing errors.
480 L<ossl_store-file(7)>
484 The use of multiple B<-signer> options and the B<-resign> command were first
485 added in OpenSSL 1.0.0
487 The -no_alt_chains option was added in OpenSSL 1.1.0.
491 Copyright 2000-2019 The OpenSSL Project Authors. All Rights Reserved.
493 Licensed under the Apache License 2.0 (the "License"). You may not use
494 this file except in compliance with the License. You can obtain a copy
495 in the file LICENSE in the source distribution or at
496 L<https://www.openssl.org/source/license.html>.