23 [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 Print out a usage message.
87 encrypt mail for the given recipient certificates. Input file is the message
88 to be encrypted. The output file is the encrypted mail in MIME format.
92 decrypt mail using the supplied certificate and private key. Expects an
93 encrypted mail message in MIME format for the input file. The decrypted mail
94 is written to the output file.
98 sign mail using the supplied certificate and private key. Input file is
99 the message to be signed. The signed message in MIME format is written
104 verify signed mail. Expects a signed mail message on input and outputs
105 the signed data. Both clear text and opaque signing is supported.
109 takes an input message and writes out a PEM encoded PKCS#7 structure.
113 resign a message: take an existing message and one or more new signers.
115 =item B<-in filename>
117 the input message to be encrypted or signed or the MIME message to
118 be decrypted or verified.
120 =item B<-inform SMIME|PEM|DER>
122 this specifies the input format for the PKCS#7 structure. The default
123 is B<SMIME> which reads an S/MIME format message. B<PEM> and B<DER>
124 format change this to expect PEM and DER format PKCS#7 structures
125 instead. This currently only affects the input format of the PKCS#7
126 structure, if no PKCS#7 structure is being input (for example with
127 B<-encrypt> or B<-sign>) this option has no effect.
129 =item B<-out filename>
131 the message text that has been decrypted or verified or the output MIME
132 format message that has been signed or verified.
134 =item B<-outform SMIME|PEM|DER>
136 this specifies the output format for the PKCS#7 structure. The default
137 is B<SMIME> which write an S/MIME format message. B<PEM> and B<DER>
138 format change this to write PEM and DER format PKCS#7 structures
139 instead. This currently only affects the output format of the PKCS#7
140 structure, if no PKCS#7 structure is being output (for example with
141 B<-verify> or B<-decrypt>) this option has no effect.
143 =item B<-stream -indef -noindef>
145 the B<-stream> and B<-indef> options are equivalent and enable streaming I/O
146 for encoding operations. This permits single pass processing of data without
147 the need to hold the entire contents in memory, potentially supporting very
148 large files. Streaming is automatically set for S/MIME signing with detached
149 data if the output format is B<SMIME> it is currently off by default for all
154 disable streaming I/O where it would produce and indefinite length constructed
155 encoding. This option currently has no effect. In future streaming will be
156 enabled by default on all relevant operations and this option will disable it.
158 =item B<-content filename>
160 This specifies a file containing the detached content, this is only
161 useful with the B<-verify> command. This is only usable if the PKCS#7
162 structure is using the detached signature form where the content is
163 not included. This option will override any content if the input format
164 is S/MIME and it uses the multipart/signed MIME content type.
168 this option adds plain text (text/plain) MIME headers to the supplied
169 message if encrypting or signing. If decrypting or verifying it strips
170 off text headers: if the decrypted or verified message is not of MIME
171 type text/plain then an error occurs.
173 =item B<-CAfile file>
175 a file containing trusted CA certificates, only used with B<-verify>.
179 a directory containing trusted CA certificates, only used with
180 B<-verify>. This directory must be a standard certificate directory: that
181 is a hash of each subject name (using B<x509 -hash>) should be linked
186 Do not load the trusted CA certificates from the default file location
190 Do not load the trusted CA certificates from the default directory location
194 digest algorithm to use when signing or resigning. If not present then the
195 default digest algorithm for the signing key will be used (usually SHA1).
199 the encryption algorithm to use. For example DES (56 bits) - B<-des>,
200 triple DES (168 bits) - B<-des3>,
201 EVP_get_cipherbyname() function) can also be used preceded by a dash, for
202 example B<-aes-128-cbc>. See L<B<enc>|enc(1)> for list of ciphers
203 supported by your version of OpenSSL.
205 If not specified triple DES is used. Only used with B<-encrypt>.
209 when verifying a message normally certificates (if any) included in
210 the message are searched for the signing certificate. With this option
211 only the certificates specified in the B<-certfile> option are used.
212 The supplied certificates can still be used as untrusted CAs however.
216 do not verify the signers certificate of a signed message.
220 do not do chain verification of signers certificates: that is don't
221 use the certificates in the signed message as untrusted CAs.
225 don't try to verify the signatures on the message.
229 when signing a message the signer's certificate is normally included
230 with this option it is excluded. This will reduce the size of the
231 signed message but the verifier must have a copy of the signers certificate
232 available locally (passed using the B<-certfile> option for example).
236 normally when a message is signed a set of attributes are included which
237 include the signing time and supported symmetric algorithms. With this
238 option they are not included.
242 normally the input message is converted to "canonical" format which is
243 effectively using CR and LF as end of line: as required by the S/MIME
244 specification. When this option is present no translation occurs. This
245 is useful when handling binary data which may not be in MIME format.
249 when signing a message use opaque signing: this form is more resistant
250 to translation by mail relays but it cannot be read by mail agents that
251 do not support S/MIME. Without this option cleartext signing with
252 the MIME type multipart/signed is used.
254 =item B<-certfile file>
256 allows additional certificates to be specified. When signing these will
257 be included with the message. When verifying these will be searched for
258 the signers certificates. The certificates should be in PEM format.
260 =item B<-signer file>
262 a signing certificate when signing or resigning a message, this option can be
263 used multiple times if more than one signer is required. If a message is being
264 verified then the signers certificates will be written to this file if the
265 verification was successful.
269 the recipients certificate when decrypting a message. This certificate
270 must match one of the recipients of the message or an error occurs.
274 the private key to use when signing or decrypting. This must match the
275 corresponding certificate. If this option is not specified then the
276 private key must be included in the certificate file specified with
277 the B<-recip> or B<-signer> file. When signing this option can be used
278 multiple times to specify successive keys.
282 the private key password source. For more information about the format of B<arg>
283 see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)>.
285 =item B<-rand file(s)>
287 a file or files containing random data used to seed the random number
288 generator, or an EGD socket (see L<RAND_egd(3)>).
289 Multiple files can be specified separated by an OS-dependent character.
290 The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for
295 one or more certificates of message recipients: used when encrypting
298 =item B<-to, -from, -subject>
300 the relevant mail headers. These are included outside the signed
301 portion of a message so they may be included manually. If signing
302 then many S/MIME mail clients check the signers certificate's email
303 address matches that specified in the From: address.
305 =item B<-attime>, B<-check_ss_sig>, B<-crl_check>, B<-crl_check_all>,
306 B<-explicit_policy>, B<-extended_crl>, B<-ignore_critical>, B<-inhibit_any>,
307 B<-inhibit_map>, B<-no_alt_chains>, B<-partial_chain>, B<-policy>,
308 B<-policy_check>, B<-policy_print>, B<-purpose>, B<-suiteB_128>,
309 B<-suiteB_128_only>, B<-suiteB_192>, B<-trusted_first>, B<-use_deltas>,
310 B<-verify_depth>, B<-verify_email>, B<-verify_hostname>, B<-verify_ip>,
311 B<-verify_name>, B<-x509_strict>
313 Set various options of certificate chain verification. See
314 L<verify(1)> manual page for details.
320 The MIME message must be sent without any blank lines between the
321 headers and the output. Some mail programs will automatically add
322 a blank line. Piping the mail directly to sendmail is one way to
323 achieve the correct format.
325 The supplied message to be signed or encrypted must include the
326 necessary MIME headers or many S/MIME clients wont display it
327 properly (if at all). You can use the B<-text> option to automatically
328 add plain text headers.
330 A "signed and encrypted" message is one where a signed message is
331 then encrypted. This can be produced by encrypting an already signed
332 message: see the examples section.
334 This version of the program only allows one signer per message but it
335 will verify multiple signers on received messages. Some S/MIME clients
336 choke if a message contains multiple signers. It is possible to sign
337 messages "in parallel" by signing an already signed message.
339 The options B<-encrypt> and B<-decrypt> reflect common usage in S/MIME
340 clients. Strictly speaking these process PKCS#7 enveloped data: PKCS#7
341 encrypted data is used for other purposes.
343 The B<-resign> option uses an existing message digest when adding a new
344 signer. This means that attributes must be present in at least one existing
345 signer using the same message digest or this operation will fail.
347 The B<-stream> and B<-indef> options enable streaming I/O support.
348 As a result the encoding is BER using indefinite length constructed encoding
349 and no longer DER. Streaming is supported for the B<-encrypt> operation and the
350 B<-sign> operation if the content is not detached.
352 Streaming is always used for the B<-sign> operation with detached data but
353 since the content is no longer part of the PKCS#7 structure the encoding
362 the operation was completely successfully.
366 an error occurred parsing the command options.
370 one of the input files could not be read.
374 an error occurred creating the PKCS#7 file or when reading the MIME
379 an error occurred decrypting or verifying the message.
383 the message was verified correctly but an error occurred writing out
384 the signers certificates.
390 Create a cleartext signed message:
392 openssl smime -sign -in message.txt -text -out mail.msg \
395 Create an opaque signed message:
397 openssl smime -sign -in message.txt -text -out mail.msg -nodetach \
400 Create a signed message, include some additional certificates and
401 read the private key from another file:
403 openssl smime -sign -in in.txt -text -out mail.msg \
404 -signer mycert.pem -inkey mykey.pem -certfile mycerts.pem
406 Create a signed message with two signers:
408 openssl smime -sign -in message.txt -text -out mail.msg \
409 -signer mycert.pem -signer othercert.pem
411 Send a signed message under Unix directly to sendmail, including headers:
413 openssl smime -sign -in in.txt -text -signer mycert.pem \
414 -from steve@openssl.org -to someone@somewhere \
415 -subject "Signed message" | sendmail someone@somewhere
417 Verify a message and extract the signer's certificate if successful:
419 openssl smime -verify -in mail.msg -signer user.pem -out signedtext.txt
421 Send encrypted mail using triple DES:
423 openssl smime -encrypt -in in.txt -from steve@openssl.org \
424 -to someone@somewhere -subject "Encrypted message" \
425 -des3 user.pem -out mail.msg
427 Sign and encrypt mail:
429 openssl smime -sign -in ml.txt -signer my.pem -text \
430 | openssl smime -encrypt -out mail.msg \
431 -from steve@openssl.org -to someone@somewhere \
432 -subject "Signed and Encrypted message" -des3 user.pem
434 Note: the encryption command does not include the B<-text> option because the
435 message being encrypted already has MIME headers.
439 openssl smime -decrypt -in mail.msg -recip mycert.pem -inkey key.pem
441 The output from Netscape form signing is a PKCS#7 structure with the
442 detached signature format. You can use this program to verify the
443 signature by line wrapping the base64 encoded structure and surrounding
446 -----BEGIN PKCS7-----
449 and using the command:
451 openssl smime -verify -inform PEM -in signature.pem -content content.txt
453 Alternatively you can base64 decode the signature and use:
455 openssl smime -verify -inform DER -in signature.der -content content.txt
457 Create an encrypted message using 128 bit Camellia:
459 openssl smime -encrypt -in plain.txt -camellia128 -out mail.msg cert.pem
461 Add a signer to an existing message:
463 openssl smime -resign -in mail.msg -signer newsign.pem -out mail2.msg
467 The MIME parser isn't very clever: it seems to handle most messages that I've
468 thrown at it but it may choke on others.
470 The code currently will only write out the signer's certificate to a file: if
471 the signer has a separate encryption certificate this must be manually
472 extracted. There should be some heuristic that determines the correct
473 encryption certificate.
475 Ideally a database should be maintained of a certificates for each email
478 The code doesn't currently take note of the permitted symmetric encryption
479 algorithms as supplied in the SMIMECapabilities signed attribute. This means the
480 user has to manually include the correct encryption algorithm. It should store
481 the list of permitted ciphers in a database and only use those.
483 No revocation checking is done on the signer's certificate.
485 The current code can only handle S/MIME v2 messages, the more complex S/MIME v3
486 structures may cause parsing errors.
490 The use of multiple B<-signer> options and the B<-resign> command were first
491 added in OpenSSL 1.0.0
493 The -no_alt_chains options was first added to OpenSSL 1.1.0.