23 [B<-attime timestamp>]
44 [B<-verify_depth num>]
45 [B<-verify_email email>]
46 [B<-verify_hostname hostname>]
48 [B<-verify_name name>]
53 [B<-inform SMIME|PEM|DER>]
57 [B<-outform SMIME|PEM|DER>]
72 The B<smime> command handles S/MIME mail. It can encrypt, decrypt, sign and
73 verify S/MIME messages.
75 =head1 COMMAND OPTIONS
77 There are six operation options that set the type of operation to be performed.
78 The meaning of the other options varies according to the operation type.
84 Print out a usage message.
88 encrypt mail for the given recipient certificates. Input file is the message
89 to be encrypted. The output file is the encrypted mail in MIME format.
93 decrypt mail using the supplied certificate and private key. Expects an
94 encrypted mail message in MIME format for the input file. The decrypted mail
95 is written to the output file.
99 sign mail using the supplied certificate and private key. Input file is
100 the message to be signed. The signed message in MIME format is written
105 verify signed mail. Expects a signed mail message on input and outputs
106 the signed data. Both clear text and opaque signing is supported.
110 takes an input message and writes out a PEM encoded PKCS#7 structure.
114 resign a message: take an existing message and one or more new signers.
116 =item B<-in filename>
118 the input message to be encrypted or signed or the MIME message to
119 be decrypted or verified.
121 =item B<-inform SMIME|PEM|DER>
123 this specifies the input format for the PKCS#7 structure. The default
124 is B<SMIME> which reads an S/MIME format message. B<PEM> and B<DER>
125 format change this to expect PEM and DER format PKCS#7 structures
126 instead. This currently only affects the input format of the PKCS#7
127 structure, if no PKCS#7 structure is being input (for example with
128 B<-encrypt> or B<-sign>) this option has no effect.
130 =item B<-out filename>
132 the message text that has been decrypted or verified or the output MIME
133 format message that has been signed or verified.
135 =item B<-outform SMIME|PEM|DER>
137 this specifies the output format for the PKCS#7 structure. The default
138 is B<SMIME> which write an S/MIME format message. B<PEM> and B<DER>
139 format change this to write PEM and DER format PKCS#7 structures
140 instead. This currently only affects the output format of the PKCS#7
141 structure, if no PKCS#7 structure is being output (for example with
142 B<-verify> or B<-decrypt>) this option has no effect.
144 =item B<-stream -indef -noindef>
146 the B<-stream> and B<-indef> options are equivalent and enable streaming I/O
147 for encoding operations. This permits single pass processing of data without
148 the need to hold the entire contents in memory, potentially supporting very
149 large files. Streaming is automatically set for S/MIME signing with detached
150 data if the output format is B<SMIME> it is currently off by default for all
155 disable streaming I/O where it would produce and indefinite length constructed
156 encoding. This option currently has no effect. In future streaming will be
157 enabled by default on all relevant operations and this option will disable it.
159 =item B<-content filename>
161 This specifies a file containing the detached content, this is only
162 useful with the B<-verify> command. This is only usable if the PKCS#7
163 structure is using the detached signature form where the content is
164 not included. This option will override any content if the input format
165 is S/MIME and it uses the multipart/signed MIME content type.
169 this option adds plain text (text/plain) MIME headers to the supplied
170 message if encrypting or signing. If decrypting or verifying it strips
171 off text headers: if the decrypted or verified message is not of MIME
172 type text/plain then an error occurs.
174 =item B<-CAfile file>
176 a file containing trusted CA certificates, only used with B<-verify>.
180 a directory containing trusted CA certificates, only used with
181 B<-verify>. This directory must be a standard certificate directory: that
182 is a hash of each subject name (using B<x509 -hash>) should be linked
187 Do not load the trusted CA certificates from the default file location
191 Do not load the trusted CA certificates from the default directory location
195 digest algorithm to use when signing or resigning. If not present then the
196 default digest algorithm for the signing key will be used (usually SHA1).
200 the encryption algorithm to use. For example DES (56 bits) - B<-des>,
201 triple DES (168 bits) - B<-des3>,
202 EVP_get_cipherbyname() function) can also be used preceded by a dash, for
203 example B<-aes-128-cbc>. See L<B<enc>|enc(1)> for list of ciphers
204 supported by your version of OpenSSL.
206 If not specified triple DES is used. Only used with B<-encrypt>.
210 when verifying a message normally certificates (if any) included in
211 the message are searched for the signing certificate. With this option
212 only the certificates specified in the B<-certfile> option are used.
213 The supplied certificates can still be used as untrusted CAs however.
217 do not verify the signers certificate of a signed message.
221 do not do chain verification of signers certificates: that is don't
222 use the certificates in the signed message as untrusted CAs.
226 don't try to verify the signatures on the message.
230 when signing a message the signer's certificate is normally included
231 with this option it is excluded. This will reduce the size of the
232 signed message but the verifier must have a copy of the signers certificate
233 available locally (passed using the B<-certfile> option for example).
237 normally when a message is signed a set of attributes are included which
238 include the signing time and supported symmetric algorithms. With this
239 option they are not included.
243 normally the input message is converted to "canonical" format which is
244 effectively using CR and LF as end of line: as required by the S/MIME
245 specification. When this option is present no translation occurs. This
246 is useful when handling binary data which may not be in MIME format.
250 when signing a message use opaque signing: this form is more resistant
251 to translation by mail relays but it cannot be read by mail agents that
252 do not support S/MIME. Without this option cleartext signing with
253 the MIME type multipart/signed is used.
255 =item B<-certfile file>
257 allows additional certificates to be specified. When signing these will
258 be included with the message. When verifying these will be searched for
259 the signers certificates. The certificates should be in PEM format.
261 =item B<-signer file>
263 a signing certificate when signing or resigning a message, this option can be
264 used multiple times if more than one signer is required. If a message is being
265 verified then the signers certificates will be written to this file if the
266 verification was successful.
270 the recipients certificate when decrypting a message. This certificate
271 must match one of the recipients of the message or an error occurs.
275 the private key to use when signing or decrypting. This must match the
276 corresponding certificate. If this option is not specified then the
277 private key must be included in the certificate file specified with
278 the B<-recip> or B<-signer> file. When signing this option can be used
279 multiple times to specify successive keys.
283 the private key password source. For more information about the format of B<arg>
284 see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)>.
286 =item B<-rand file(s)>
288 a file or files containing random data used to seed the random number
289 generator, or an EGD socket (see L<RAND_egd(3)>).
290 Multiple files can be specified separated by an OS-dependent character.
291 The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for
296 one or more certificates of message recipients: used when encrypting
299 =item B<-to, -from, -subject>
301 the relevant mail headers. These are included outside the signed
302 portion of a message so they may be included manually. If signing
303 then many S/MIME mail clients check the signers certificate's email
304 address matches that specified in the From: address.
306 =item B<-attime>, B<-check_ss_sig>, B<-crl_check>, B<-crl_check_all>,
307 B<-explicit_policy>, B<-extended_crl>, B<-ignore_critical>, B<-inhibit_any>,
308 B<-inhibit_map>, B<-no_alt_chains>, B<-partial_chain>, B<-policy>,
309 B<-policy_check>, B<-policy_print>, B<-purpose>, B<-suiteB_128>,
310 B<-suiteB_128_only>, B<-suiteB_192>, B<-trusted_first>, B<-use_deltas>,
311 B<-auth_level>, B<-verify_depth>, B<-verify_email>, B<-verify_hostname>,
312 B<-verify_ip>, B<-verify_name>, B<-x509_strict>
314 Set various options of certificate chain verification. See
315 L<verify(1)> manual page for details.
321 The MIME message must be sent without any blank lines between the
322 headers and the output. Some mail programs will automatically add
323 a blank line. Piping the mail directly to sendmail is one way to
324 achieve the correct format.
326 The supplied message to be signed or encrypted must include the
327 necessary MIME headers or many S/MIME clients wont display it
328 properly (if at all). You can use the B<-text> option to automatically
329 add plain text headers.
331 A "signed and encrypted" message is one where a signed message is
332 then encrypted. This can be produced by encrypting an already signed
333 message: see the examples section.
335 This version of the program only allows one signer per message but it
336 will verify multiple signers on received messages. Some S/MIME clients
337 choke if a message contains multiple signers. It is possible to sign
338 messages "in parallel" by signing an already signed message.
340 The options B<-encrypt> and B<-decrypt> reflect common usage in S/MIME
341 clients. Strictly speaking these process PKCS#7 enveloped data: PKCS#7
342 encrypted data is used for other purposes.
344 The B<-resign> option uses an existing message digest when adding a new
345 signer. This means that attributes must be present in at least one existing
346 signer using the same message digest or this operation will fail.
348 The B<-stream> and B<-indef> options enable streaming I/O support.
349 As a result the encoding is BER using indefinite length constructed encoding
350 and no longer DER. Streaming is supported for the B<-encrypt> operation and the
351 B<-sign> operation if the content is not detached.
353 Streaming is always used for the B<-sign> operation with detached data but
354 since the content is no longer part of the PKCS#7 structure the encoding
363 the operation was completely successfully.
367 an error occurred parsing the command options.
371 one of the input files could not be read.
375 an error occurred creating the PKCS#7 file or when reading the MIME
380 an error occurred decrypting or verifying the message.
384 the message was verified correctly but an error occurred writing out
385 the signers certificates.
391 Create a cleartext signed message:
393 openssl smime -sign -in message.txt -text -out mail.msg \
396 Create an opaque signed message:
398 openssl smime -sign -in message.txt -text -out mail.msg -nodetach \
401 Create a signed message, include some additional certificates and
402 read the private key from another file:
404 openssl smime -sign -in in.txt -text -out mail.msg \
405 -signer mycert.pem -inkey mykey.pem -certfile mycerts.pem
407 Create a signed message with two signers:
409 openssl smime -sign -in message.txt -text -out mail.msg \
410 -signer mycert.pem -signer othercert.pem
412 Send a signed message under Unix directly to sendmail, including headers:
414 openssl smime -sign -in in.txt -text -signer mycert.pem \
415 -from steve@openssl.org -to someone@somewhere \
416 -subject "Signed message" | sendmail someone@somewhere
418 Verify a message and extract the signer's certificate if successful:
420 openssl smime -verify -in mail.msg -signer user.pem -out signedtext.txt
422 Send encrypted mail using triple DES:
424 openssl smime -encrypt -in in.txt -from steve@openssl.org \
425 -to someone@somewhere -subject "Encrypted message" \
426 -des3 user.pem -out mail.msg
428 Sign and encrypt mail:
430 openssl smime -sign -in ml.txt -signer my.pem -text \
431 | openssl smime -encrypt -out mail.msg \
432 -from steve@openssl.org -to someone@somewhere \
433 -subject "Signed and Encrypted message" -des3 user.pem
435 Note: the encryption command does not include the B<-text> option because the
436 message being encrypted already has MIME headers.
440 openssl smime -decrypt -in mail.msg -recip mycert.pem -inkey key.pem
442 The output from Netscape form signing is a PKCS#7 structure with the
443 detached signature format. You can use this program to verify the
444 signature by line wrapping the base64 encoded structure and surrounding
447 -----BEGIN PKCS7-----
450 and using the command:
452 openssl smime -verify -inform PEM -in signature.pem -content content.txt
454 Alternatively you can base64 decode the signature and use:
456 openssl smime -verify -inform DER -in signature.der -content content.txt
458 Create an encrypted message using 128 bit Camellia:
460 openssl smime -encrypt -in plain.txt -camellia128 -out mail.msg cert.pem
462 Add a signer to an existing message:
464 openssl smime -resign -in mail.msg -signer newsign.pem -out mail2.msg
468 The MIME parser isn't very clever: it seems to handle most messages that I've
469 thrown at it but it may choke on others.
471 The code currently will only write out the signer's certificate to a file: if
472 the signer has a separate encryption certificate this must be manually
473 extracted. There should be some heuristic that determines the correct
474 encryption certificate.
476 Ideally a database should be maintained of a certificates for each email
479 The code doesn't currently take note of the permitted symmetric encryption
480 algorithms as supplied in the SMIMECapabilities signed attribute. This means the
481 user has to manually include the correct encryption algorithm. It should store
482 the list of permitted ciphers in a database and only use those.
484 No revocation checking is done on the signer's certificate.
486 The current code can only handle S/MIME v2 messages, the more complex S/MIME v3
487 structures may cause parsing errors.
491 The use of multiple B<-signer> options and the B<-resign> command were first
492 added in OpenSSL 1.0.0
494 The -no_alt_chains options was first added to OpenSSL 1.1.0.