31 [B<-inform SMIME|PEM|DER>]
35 [B<-outform SMIME|PEM|DER>]
47 The B<smime> command handles S/MIME mail. It can encrypt, decrypt, sign and
48 verify S/MIME messages.
50 =head1 COMMAND OPTIONS
52 There are five operation options that set the type of operation to be performed.
53 The meaning of the other options varies according to the operation type.
59 encrypt mail for the given recipient certificates. Input file is the message
60 to be encrypted. The output file is the encrypted mail in MIME format.
64 decrypt mail using the supplied certificate and private key. Expects an
65 encrypted mail message in MIME format for the input file. The decrypted mail
66 is written to the output file.
70 sign mail using the supplied certificate and private key. Input file is
71 the message to be signed. The signed message in MIME format is written
76 verify signed mail. Expects a signed mail message on input and outputs
77 the signed data. Both clear text and opaque signing is supported.
81 takes an input message and writes out a PEM encoded PKCS#7 structure.
85 resign a message: take an existing message and one or more new signers.
89 the input message to be encrypted or signed or the MIME message to
90 be decrypted or verified.
92 =item B<-inform SMIME|PEM|DER>
94 this specifies the input format for the PKCS#7 structure. The default
95 is B<SMIME> which reads an S/MIME format message. B<PEM> and B<DER>
96 format change this to expect PEM and DER format PKCS#7 structures
97 instead. This currently only affects the input format of the PKCS#7
98 structure, if no PKCS#7 structure is being input (for example with
99 B<-encrypt> or B<-sign>) this option has no effect.
101 =item B<-out filename>
103 the message text that has been decrypted or verified or the output MIME
104 format message that has been signed or verified.
106 =item B<-outform SMIME|PEM|DER>
108 this specifies the output format for the PKCS#7 structure. The default
109 is B<SMIME> which write an S/MIME format message. B<PEM> and B<DER>
110 format change this to write PEM and DER format PKCS#7 structures
111 instead. This currently only affects the output format of the PKCS#7
112 structure, if no PKCS#7 structure is being output (for example with
113 B<-verify> or B<-decrypt>) this option has no effect.
115 =item B<-content filename>
117 This specifies a file containing the detached content, this is only
118 useful with the B<-verify> command. This is only usable if the PKCS#7
119 structure is using the detached signature form where the content is
120 not included. This option will override any content if the input format
121 is S/MIME and it uses the multipart/signed MIME content type.
125 this option adds plain text (text/plain) MIME headers to the supplied
126 message if encrypting or signing. If decrypting or verifying it strips
127 off text headers: if the decrypted or verified message is not of MIME
128 type text/plain then an error occurs.
130 =item B<-CAfile file>
132 a file containing trusted CA certificates, only used with B<-verify>.
136 a directory containing trusted CA certificates, only used with
137 B<-verify>. This directory must be a standard certificate directory: that
138 is a hash of each subject name (using B<x509 -hash>) should be linked
143 digest algorithm to use when signing or resigning. If not present then the
144 default digest algorithm for the signing key will be used (usually SHA1).
146 =item B<-des -des3 -rc2-40 -rc2-64 -rc2-128 -aes128 -aes192 -aes256 -camellia128 -camellia192 -camellia256>
148 the encryption algorithm to use. DES (56 bits), triple DES (168 bits), 40, 64
149 or 128 bit RC2, 128, 192 or 256 bit AES, or 128, 192 or 256 bit Camellia
150 respectively. Any other cipher name (as recognized by the
151 EVP_get_cipherbyname() function) can also be used preceded by a dash, for
152 example B<-aes_128_cbc>.
154 If not specified 40 bit RC2 is used. Only used with B<-encrypt>.
158 when verifying a message normally certificates (if any) included in
159 the message are searched for the signing certificate. With this option
160 only the certificates specified in the B<-certfile> option are used.
161 The supplied certificates can still be used as untrusted CAs however.
165 do not verify the signers certificate of a signed message.
169 do not do chain verification of signers certificates: that is don't
170 use the certificates in the signed message as untrusted CAs.
174 don't try to verify the signatures on the message.
178 when signing a message the signer's certificate is normally included
179 with this option it is excluded. This will reduce the size of the
180 signed message but the verifier must have a copy of the signers certificate
181 available locally (passed using the B<-certfile> option for example).
185 normally when a message is signed a set of attributes are included which
186 include the signing time and supported symmetric algorithms. With this
187 option they are not included.
191 normally the input message is converted to "canonical" format which is
192 effectively using CR and LF as end of line: as required by the S/MIME
193 specification. When this option is present no translation occurs. This
194 is useful when handling binary data which may not be in MIME format.
198 when signing a message use opaque signing: this form is more resistant
199 to translation by mail relays but it cannot be read by mail agents that
200 do not support S/MIME. Without this option cleartext signing with
201 the MIME type multipart/signed is used.
203 =item B<-certfile file>
205 allows additional certificates to be specified. When signing these will
206 be included with the message. When verifying these will be searched for
207 the signers certificates. The certificates should be in PEM format.
209 =item B<-signer file>
211 a signing certificate when signing or resigning a message, this option can be
212 used multiple times if more than one signer is required. If a message is being
213 verified then the signers certificates will be written to this file if the
214 verification was successful.
218 the recipients certificate when decrypting a message. This certificate
219 must match one of the recipients of the message or an error occurs.
223 the private key to use when signing or decrypting. This must match the
224 corresponding certificate. If this option is not specified then the
225 private key must be included in the certificate file specified with
226 the B<-recip> or B<-signer> file. When signing this option can be used
227 multiple times to specify successive keys.
231 the private key password source. For more information about the format of B<arg>
232 see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)|openssl(1)>.
234 =item B<-rand file(s)>
236 a file or files containing random data used to seed the random number
237 generator, or an EGD socket (see L<RAND_egd(3)|RAND_egd(3)>).
238 Multiple files can be specified separated by a OS-dependent character.
239 The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for
244 one or more certificates of message recipients: used when encrypting
247 =item B<-to, -from, -subject>
249 the relevant mail headers. These are included outside the signed
250 portion of a message so they may be included manually. If signing
251 then many S/MIME mail clients check the signers certificate's email
252 address matches that specified in the From: address.
258 The MIME message must be sent without any blank lines between the
259 headers and the output. Some mail programs will automatically add
260 a blank line. Piping the mail directly to sendmail is one way to
261 achieve the correct format.
263 The supplied message to be signed or encrypted must include the
264 necessary MIME headers or many S/MIME clients wont display it
265 properly (if at all). You can use the B<-text> option to automatically
266 add plain text headers.
268 A "signed and encrypted" message is one where a signed message is
269 then encrypted. This can be produced by encrypting an already signed
270 message: see the examples section.
272 This version of the program only allows one signer per message but it
273 will verify multiple signers on received messages. Some S/MIME clients
274 choke if a message contains multiple signers. It is possible to sign
275 messages "in parallel" by signing an already signed message.
277 The options B<-encrypt> and B<-decrypt> reflect common usage in S/MIME
278 clients. Strictly speaking these process PKCS#7 enveloped data: PKCS#7
279 encrypted data is used for other purposes.
281 The B<-resign> option uses an existing message digest when adding a new
282 signer. This means that attributes must be present in at least one existing
283 signer using the same message digest or this operation will fail.
291 the operation was completely successfully.
295 an error occurred parsing the command options.
299 one of the input files could not be read.
303 an error occurred creating the PKCS#7 file or when reading the MIME
308 an error occurred decrypting or verifying the message.
312 the message was verified correctly but an error occurred writing out
313 the signers certificates.
319 Create a cleartext signed message:
321 openssl smime -sign -in message.txt -text -out mail.msg \
324 Create an opaque signed message
326 openssl smime -sign -in message.txt -text -out mail.msg -nodetach \
329 Create a signed message, include some additional certificates and
330 read the private key from another file:
332 openssl smime -sign -in in.txt -text -out mail.msg \
333 -signer mycert.pem -inkey mykey.pem -certfile mycerts.pem
335 Create a signed message with two signers:
337 openssl smime -sign -in message.txt -text -out mail.msg \
338 -signer mycert.pem -signer othercert.pem
340 Send a signed message under Unix directly to sendmail, including headers:
342 openssl smime -sign -in in.txt -text -signer mycert.pem \
343 -from steve@openssl.org -to someone@somewhere \
344 -subject "Signed message" | sendmail someone@somewhere
346 Verify a message and extract the signer's certificate if successful:
348 openssl smime -verify -in mail.msg -signer user.pem -out signedtext.txt
350 Send encrypted mail using triple DES:
352 openssl smime -encrypt -in in.txt -from steve@openssl.org \
353 -to someone@somewhere -subject "Encrypted message" \
354 -des3 user.pem -out mail.msg
356 Sign and encrypt mail:
358 openssl smime -sign -in ml.txt -signer my.pem -text \
359 | openssl smime -encrypt -out mail.msg \
360 -from steve@openssl.org -to someone@somewhere \
361 -subject "Signed and Encrypted message" -des3 user.pem
363 Note: the encryption command does not include the B<-text> option because the
364 message being encrypted already has MIME headers.
368 openssl smime -decrypt -in mail.msg -recip mycert.pem -inkey key.pem
370 The output from Netscape form signing is a PKCS#7 structure with the
371 detached signature format. You can use this program to verify the
372 signature by line wrapping the base64 encoded structure and surrounding
375 -----BEGIN PKCS7-----
378 and using the command,
380 openssl smime -verify -inform PEM -in signature.pem -content content.txt
382 alternatively you can base64 decode the signature and use
384 openssl smime -verify -inform DER -in signature.der -content content.txt
386 Create an encrypted message using 128 bit Camellia:
388 openssl smime -encrypt -in plain.txt -camellia128 -out mail.msg cert.pem
390 Add a signer to an existing message:
392 openssl smime -resign -in mail.msg -signer newsign.pem -out mail2.msg
396 The MIME parser isn't very clever: it seems to handle most messages that I've
397 thrown at it but it may choke on others.
399 The code currently will only write out the signer's certificate to a file: if
400 the signer has a separate encryption certificate this must be manually
401 extracted. There should be some heuristic that determines the correct
402 encryption certificate.
404 Ideally a database should be maintained of a certificates for each email
407 The code doesn't currently take note of the permitted symmetric encryption
408 algorithms as supplied in the SMIMECapabilities signed attribute. this means the
409 user has to manually include the correct encryption algorithm. It should store
410 the list of permitted ciphers in a database and only use those.
412 No revocation checking is done on the signer's certificate.
414 The current code can only handle S/MIME v2 messages, the more complex S/MIME v3
415 structures may cause parsing errors.
419 The use of multiple B<-signer> options and the B<-resign> command were first
420 added in OpenSSL 0.9.9