31 [B<-inform SMIME|PEM|DER>]
35 [B<-outform SMIME|PEM|DER>]
50 The B<smime> command handles S/MIME mail. It can encrypt, decrypt, sign and
51 verify S/MIME messages.
53 =head1 COMMAND OPTIONS
55 There are six operation options that set the type of operation to be performed.
56 The meaning of the other options varies according to the operation type.
62 encrypt mail for the given recipient certificates. Input file is the message
63 to be encrypted. The output file is the encrypted mail in MIME format.
67 decrypt mail using the supplied certificate and private key. Expects an
68 encrypted mail message in MIME format for the input file. The decrypted mail
69 is written to the output file.
73 sign mail using the supplied certificate and private key. Input file is
74 the message to be signed. The signed message in MIME format is written
79 verify signed mail. Expects a signed mail message on input and outputs
80 the signed data. Both clear text and opaque signing is supported.
84 takes an input message and writes out a PEM encoded PKCS#7 structure.
88 resign a message: take an existing message and one or more new signers.
92 the input message to be encrypted or signed or the MIME message to
93 be decrypted or verified.
95 =item B<-inform SMIME|PEM|DER>
97 this specifies the input format for the PKCS#7 structure. The default
98 is B<SMIME> which reads an S/MIME format message. B<PEM> and B<DER>
99 format change this to expect PEM and DER format PKCS#7 structures
100 instead. This currently only affects the input format of the PKCS#7
101 structure, if no PKCS#7 structure is being input (for example with
102 B<-encrypt> or B<-sign>) this option has no effect.
104 =item B<-out filename>
106 the message text that has been decrypted or verified or the output MIME
107 format message that has been signed or verified.
109 =item B<-outform SMIME|PEM|DER>
111 this specifies the output format for the PKCS#7 structure. The default
112 is B<SMIME> which write an S/MIME format message. B<PEM> and B<DER>
113 format change this to write PEM and DER format PKCS#7 structures
114 instead. This currently only affects the output format of the PKCS#7
115 structure, if no PKCS#7 structure is being output (for example with
116 B<-verify> or B<-decrypt>) this option has no effect.
118 =item B<-stream -indef -noindef>
120 the B<-stream> and B<-indef> options are equivalent and enable streaming I/O
121 for encoding operations. This permits single pass processing of data without
122 the need to hold the entire contents in memory, potentially supporting very
123 large files. Streaming is automatically set for S/MIME signing with detached
124 data if the output format is B<SMIME> it is currently off by default for all
129 disable streaming I/O where it would produce and indefinite length constructed
130 encoding. This option currently has no effect. In future streaming will be
131 enabled by default on all relevant operations and this option will disable it.
133 =item B<-content filename>
135 This specifies a file containing the detached content, this is only
136 useful with the B<-verify> command. This is only usable if the PKCS#7
137 structure is using the detached signature form where the content is
138 not included. This option will override any content if the input format
139 is S/MIME and it uses the multipart/signed MIME content type.
143 this option adds plain text (text/plain) MIME headers to the supplied
144 message if encrypting or signing. If decrypting or verifying it strips
145 off text headers: if the decrypted or verified message is not of MIME
146 type text/plain then an error occurs.
148 =item B<-CAfile file>
150 a file containing trusted CA certificates, only used with B<-verify>.
154 a directory containing trusted CA certificates, only used with
155 B<-verify>. This directory must be a standard certificate directory: that
156 is a hash of each subject name (using B<x509 -hash>) should be linked
161 digest algorithm to use when signing or resigning. If not present then the
162 default digest algorithm for the signing key will be used (usually SHA1).
164 =item B<-des -des3 -rc2-40 -rc2-64 -rc2-128 -aes128 -aes192 -aes256 -camellia128 -camellia192 -camellia256>
166 the encryption algorithm to use. DES (56 bits), triple DES (168 bits), 40, 64
167 or 128 bit RC2, 128, 192 or 256 bit AES, or 128, 192 or 256 bit Camellia
168 respectively. Any other cipher name (as recognized by the
169 EVP_get_cipherbyname() function) can also be used preceded by a dash, for
170 example B<-aes_128_cbc>.
172 If not specified 40 bit RC2 is used. Only used with B<-encrypt>.
176 when verifying a message normally certificates (if any) included in
177 the message are searched for the signing certificate. With this option
178 only the certificates specified in the B<-certfile> option are used.
179 The supplied certificates can still be used as untrusted CAs however.
183 do not verify the signers certificate of a signed message.
187 do not do chain verification of signers certificates: that is don't
188 use the certificates in the signed message as untrusted CAs.
192 don't try to verify the signatures on the message.
196 when signing a message the signer's certificate is normally included
197 with this option it is excluded. This will reduce the size of the
198 signed message but the verifier must have a copy of the signers certificate
199 available locally (passed using the B<-certfile> option for example).
203 normally when a message is signed a set of attributes are included which
204 include the signing time and supported symmetric algorithms. With this
205 option they are not included.
209 normally the input message is converted to "canonical" format which is
210 effectively using CR and LF as end of line: as required by the S/MIME
211 specification. When this option is present no translation occurs. This
212 is useful when handling binary data which may not be in MIME format.
216 when signing a message use opaque signing: this form is more resistant
217 to translation by mail relays but it cannot be read by mail agents that
218 do not support S/MIME. Without this option cleartext signing with
219 the MIME type multipart/signed is used.
221 =item B<-certfile file>
223 allows additional certificates to be specified. When signing these will
224 be included with the message. When verifying these will be searched for
225 the signers certificates. The certificates should be in PEM format.
227 =item B<-signer file>
229 a signing certificate when signing or resigning a message, this option can be
230 used multiple times if more than one signer is required. If a message is being
231 verified then the signers certificates will be written to this file if the
232 verification was successful.
236 the recipients certificate when decrypting a message. This certificate
237 must match one of the recipients of the message or an error occurs.
241 the private key to use when signing or decrypting. This must match the
242 corresponding certificate. If this option is not specified then the
243 private key must be included in the certificate file specified with
244 the B<-recip> or B<-signer> file. When signing this option can be used
245 multiple times to specify successive keys.
249 the private key password source. For more information about the format of B<arg>
250 see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)|openssl(1)>.
252 =item B<-rand file(s)>
254 a file or files containing random data used to seed the random number
255 generator, or an EGD socket (see L<RAND_egd(3)|RAND_egd(3)>).
256 Multiple files can be specified separated by a OS-dependent character.
257 The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for
262 one or more certificates of message recipients: used when encrypting
265 =item B<-to, -from, -subject>
267 the relevant mail headers. These are included outside the signed
268 portion of a message so they may be included manually. If signing
269 then many S/MIME mail clients check the signers certificate's email
270 address matches that specified in the From: address.
276 The MIME message must be sent without any blank lines between the
277 headers and the output. Some mail programs will automatically add
278 a blank line. Piping the mail directly to sendmail is one way to
279 achieve the correct format.
281 The supplied message to be signed or encrypted must include the
282 necessary MIME headers or many S/MIME clients wont display it
283 properly (if at all). You can use the B<-text> option to automatically
284 add plain text headers.
286 A "signed and encrypted" message is one where a signed message is
287 then encrypted. This can be produced by encrypting an already signed
288 message: see the examples section.
290 This version of the program only allows one signer per message but it
291 will verify multiple signers on received messages. Some S/MIME clients
292 choke if a message contains multiple signers. It is possible to sign
293 messages "in parallel" by signing an already signed message.
295 The options B<-encrypt> and B<-decrypt> reflect common usage in S/MIME
296 clients. Strictly speaking these process PKCS#7 enveloped data: PKCS#7
297 encrypted data is used for other purposes.
299 The B<-resign> option uses an existing message digest when adding a new
300 signer. This means that attributes must be present in at least one existing
301 signer using the same message digest or this operation will fail.
303 The B<-stream> and B<-indef> options enable experimental streaming I/O support.
304 As a result the encoding is BER using indefinite length constructed encoding
305 and no longer DER. Streaming is supported for the B<-encrypt> operation and the
306 B<-sign> operation if the content is not detached.
308 Streaming is always used for the B<-sign> operation with detached data but
309 since the content is no longer part of the PKCS#7 structure the encoding
318 the operation was completely successfully.
322 an error occurred parsing the command options.
326 one of the input files could not be read.
330 an error occurred creating the PKCS#7 file or when reading the MIME
335 an error occurred decrypting or verifying the message.
339 the message was verified correctly but an error occurred writing out
340 the signers certificates.
346 Create a cleartext signed message:
348 openssl smime -sign -in message.txt -text -out mail.msg \
351 Create an opaque signed message
353 openssl smime -sign -in message.txt -text -out mail.msg -nodetach \
356 Create a signed message, include some additional certificates and
357 read the private key from another file:
359 openssl smime -sign -in in.txt -text -out mail.msg \
360 -signer mycert.pem -inkey mykey.pem -certfile mycerts.pem
362 Create a signed message with two signers:
364 openssl smime -sign -in message.txt -text -out mail.msg \
365 -signer mycert.pem -signer othercert.pem
367 Send a signed message under Unix directly to sendmail, including headers:
369 openssl smime -sign -in in.txt -text -signer mycert.pem \
370 -from steve@openssl.org -to someone@somewhere \
371 -subject "Signed message" | sendmail someone@somewhere
373 Verify a message and extract the signer's certificate if successful:
375 openssl smime -verify -in mail.msg -signer user.pem -out signedtext.txt
377 Send encrypted mail using triple DES:
379 openssl smime -encrypt -in in.txt -from steve@openssl.org \
380 -to someone@somewhere -subject "Encrypted message" \
381 -des3 user.pem -out mail.msg
383 Sign and encrypt mail:
385 openssl smime -sign -in ml.txt -signer my.pem -text \
386 | openssl smime -encrypt -out mail.msg \
387 -from steve@openssl.org -to someone@somewhere \
388 -subject "Signed and Encrypted message" -des3 user.pem
390 Note: the encryption command does not include the B<-text> option because the
391 message being encrypted already has MIME headers.
395 openssl smime -decrypt -in mail.msg -recip mycert.pem -inkey key.pem
397 The output from Netscape form signing is a PKCS#7 structure with the
398 detached signature format. You can use this program to verify the
399 signature by line wrapping the base64 encoded structure and surrounding
402 -----BEGIN PKCS7-----
405 and using the command,
407 openssl smime -verify -inform PEM -in signature.pem -content content.txt
409 alternatively you can base64 decode the signature and use
411 openssl smime -verify -inform DER -in signature.der -content content.txt
413 Create an encrypted message using 128 bit Camellia:
415 openssl smime -encrypt -in plain.txt -camellia128 -out mail.msg cert.pem
417 Add a signer to an existing message:
419 openssl smime -resign -in mail.msg -signer newsign.pem -out mail2.msg
423 The MIME parser isn't very clever: it seems to handle most messages that I've
424 thrown at it but it may choke on others.
426 The code currently will only write out the signer's certificate to a file: if
427 the signer has a separate encryption certificate this must be manually
428 extracted. There should be some heuristic that determines the correct
429 encryption certificate.
431 Ideally a database should be maintained of a certificates for each email
434 The code doesn't currently take note of the permitted symmetric encryption
435 algorithms as supplied in the SMIMECapabilities signed attribute. this means the
436 user has to manually include the correct encryption algorithm. It should store
437 the list of permitted ciphers in a database and only use those.
439 No revocation checking is done on the signer's certificate.
441 The current code can only handle S/MIME v2 messages, the more complex S/MIME v3
442 structures may cause parsing errors.
446 The use of multiple B<-signer> options and the B<-resign> command were first
447 added in OpenSSL 0.9.9