Import OpenSSL-1.0.1h.
[dragonfly.git] / crypto / openssl / doc / apps / smime.pod
CommitLineData
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1=pod
2
3=head1 NAME
4
5smime - S/MIME utility
6
7=head1 SYNOPSIS
8
9B<openssl> B<smime>
10[B<-encrypt>]
11[B<-decrypt>]
12[B<-sign>]
919b01cc 13[B<-resign>]
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14[B<-verify>]
15[B<-pk7out>]
919b01cc 16[B<-[cipher]>]
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17[B<-in file>]
18[B<-certfile file>]
19[B<-signer file>]
20[B<-recip file>]
21[B<-inform SMIME|PEM|DER>]
22[B<-passin arg>]
23[B<-inkey file>]
24[B<-out file>]
25[B<-outform SMIME|PEM|DER>]
26[B<-content file>]
27[B<-to addr>]
28[B<-from ad>]
29[B<-subject s>]
30[B<-text>]
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31[B<-indef>]
32[B<-noindef>]
33[B<-stream>]
730b1645 34[B<-rand file(s)>]
919b01cc 35[B<-md digest>]
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36[cert.pem]...
37
38=head1 DESCRIPTION
39
40The B<smime> command handles S/MIME mail. It can encrypt, decrypt, sign and
41verify S/MIME messages.
42
43=head1 COMMAND OPTIONS
44
919b01cc 45There are six operation options that set the type of operation to be performed.
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46The meaning of the other options varies according to the operation type.
47
48=over 4
49
50=item B<-encrypt>
51
52encrypt mail for the given recipient certificates. Input file is the message
53to be encrypted. The output file is the encrypted mail in MIME format.
54
55=item B<-decrypt>
56
57decrypt mail using the supplied certificate and private key. Expects an
58encrypted mail message in MIME format for the input file. The decrypted mail
59is written to the output file.
60
61=item B<-sign>
62
63sign mail using the supplied certificate and private key. Input file is
64the message to be signed. The signed message in MIME format is written
65to the output file.
66
67=item B<-verify>
68
69verify signed mail. Expects a signed mail message on input and outputs
70the signed data. Both clear text and opaque signing is supported.
71
72=item B<-pk7out>
73
74takes an input message and writes out a PEM encoded PKCS#7 structure.
75
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76=item B<-resign>
77
78resign a message: take an existing message and one or more new signers.
79
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80=item B<-in filename>
81
82the input message to be encrypted or signed or the MIME message to
83be decrypted or verified.
84
85=item B<-inform SMIME|PEM|DER>
86
87this specifies the input format for the PKCS#7 structure. The default
88is B<SMIME> which reads an S/MIME format message. B<PEM> and B<DER>
89format change this to expect PEM and DER format PKCS#7 structures
90instead. This currently only affects the input format of the PKCS#7
91structure, if no PKCS#7 structure is being input (for example with
92B<-encrypt> or B<-sign>) this option has no effect.
93
94=item B<-out filename>
95
96the message text that has been decrypted or verified or the output MIME
97format message that has been signed or verified.
98
99=item B<-outform SMIME|PEM|DER>
100
101this specifies the output format for the PKCS#7 structure. The default
102is B<SMIME> which write an S/MIME format message. B<PEM> and B<DER>
103format change this to write PEM and DER format PKCS#7 structures
104instead. This currently only affects the output format of the PKCS#7
105structure, if no PKCS#7 structure is being output (for example with
106B<-verify> or B<-decrypt>) this option has no effect.
107
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108=item B<-stream -indef -noindef>
109
110the B<-stream> and B<-indef> options are equivalent and enable streaming I/O
111for encoding operations. This permits single pass processing of data without
112the need to hold the entire contents in memory, potentially supporting very
113large files. Streaming is automatically set for S/MIME signing with detached
114data if the output format is B<SMIME> it is currently off by default for all
115other operations.
116
117=item B<-noindef>
118
119disable streaming I/O where it would produce and indefinite length constructed
120encoding. This option currently has no effect. In future streaming will be
121enabled by default on all relevant operations and this option will disable it.
122
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123=item B<-content filename>
124
125This specifies a file containing the detached content, this is only
126useful with the B<-verify> command. This is only usable if the PKCS#7
127structure is using the detached signature form where the content is
128not included. This option will override any content if the input format
129is S/MIME and it uses the multipart/signed MIME content type.
130
131=item B<-text>
132
133this option adds plain text (text/plain) MIME headers to the supplied
134message if encrypting or signing. If decrypting or verifying it strips
135off text headers: if the decrypted or verified message is not of MIME
136type text/plain then an error occurs.
137
138=item B<-CAfile file>
139
140a file containing trusted CA certificates, only used with B<-verify>.
141
142=item B<-CApath dir>
143
144a directory containing trusted CA certificates, only used with
145B<-verify>. This directory must be a standard certificate directory: that
146is a hash of each subject name (using B<x509 -hash>) should be linked
147to each certificate.
148
919b01cc 149=item B<-md digest>
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151digest algorithm to use when signing or resigning. If not present then the
152default digest algorithm for the signing key will be used (usually SHA1).
153
154=item B<-[cipher]>
155
156the encryption algorithm to use. For example DES (56 bits) - B<-des>,
157triple DES (168 bits) - B<-des3>,
158EVP_get_cipherbyname() function) can also be used preceded by a dash, for
159example B<-aes_128_cbc>. See L<B<enc>|enc(1)> for list of ciphers
160supported by your version of OpenSSL.
161
4bb195ec 162If not specified triple DES is used. Only used with B<-encrypt>.
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163
164=item B<-nointern>
165
166when verifying a message normally certificates (if any) included in
167the message are searched for the signing certificate. With this option
168only the certificates specified in the B<-certfile> option are used.
169The supplied certificates can still be used as untrusted CAs however.
170
171=item B<-noverify>
172
173do not verify the signers certificate of a signed message.
174
175=item B<-nochain>
176
177do not do chain verification of signers certificates: that is don't
178use the certificates in the signed message as untrusted CAs.
179
180=item B<-nosigs>
181
182don't try to verify the signatures on the message.
183
184=item B<-nocerts>
185
186when signing a message the signer's certificate is normally included
187with this option it is excluded. This will reduce the size of the
188signed message but the verifier must have a copy of the signers certificate
189available locally (passed using the B<-certfile> option for example).
190
191=item B<-noattr>
192
193normally when a message is signed a set of attributes are included which
194include the signing time and supported symmetric algorithms. With this
195option they are not included.
196
197=item B<-binary>
198
199normally the input message is converted to "canonical" format which is
200effectively using CR and LF as end of line: as required by the S/MIME
201specification. When this option is present no translation occurs. This
202is useful when handling binary data which may not be in MIME format.
203
204=item B<-nodetach>
205
206when signing a message use opaque signing: this form is more resistant
207to translation by mail relays but it cannot be read by mail agents that
208do not support S/MIME. Without this option cleartext signing with
209the MIME type multipart/signed is used.
210
211=item B<-certfile file>
212
213allows additional certificates to be specified. When signing these will
214be included with the message. When verifying these will be searched for
215the signers certificates. The certificates should be in PEM format.
216
217=item B<-signer file>
218
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219a signing certificate when signing or resigning a message, this option can be
220used multiple times if more than one signer is required. If a message is being
221verified then the signers certificates will be written to this file if the
222verification was successful.
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223
224=item B<-recip file>
225
226the recipients certificate when decrypting a message. This certificate
227must match one of the recipients of the message or an error occurs.
228
229=item B<-inkey file>
230
231the private key to use when signing or decrypting. This must match the
232corresponding certificate. If this option is not specified then the
233private key must be included in the certificate file specified with
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234the B<-recip> or B<-signer> file. When signing this option can be used
235multiple times to specify successive keys.
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236
237=item B<-passin arg>
238
239the private key password source. For more information about the format of B<arg>
240see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)|openssl(1)>.
241
242=item B<-rand file(s)>
243
244a file or files containing random data used to seed the random number
245generator, or an EGD socket (see L<RAND_egd(3)|RAND_egd(3)>).
246Multiple files can be specified separated by a OS-dependent character.
247The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for
248all others.
249
250=item B<cert.pem...>
251
252one or more certificates of message recipients: used when encrypting
253a message.
254
255=item B<-to, -from, -subject>
256
257the relevant mail headers. These are included outside the signed
258portion of a message so they may be included manually. If signing
259then many S/MIME mail clients check the signers certificate's email
260address matches that specified in the From: address.
261
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262=item B<-purpose, -ignore_critical, -issuer_checks, -crl_check, -crl_check_all, -policy_check, -extended_crl, -x509_strict, -policy -check_ss_sig>
263
264Set various options of certificate chain verification. See
265L<B<verify>|verify(1)> manual page for details.
266
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267=back
268
269=head1 NOTES
270
271The MIME message must be sent without any blank lines between the
272headers and the output. Some mail programs will automatically add
273a blank line. Piping the mail directly to sendmail is one way to
274achieve the correct format.
275
276The supplied message to be signed or encrypted must include the
277necessary MIME headers or many S/MIME clients wont display it
278properly (if at all). You can use the B<-text> option to automatically
279add plain text headers.
280
281A "signed and encrypted" message is one where a signed message is
282then encrypted. This can be produced by encrypting an already signed
283message: see the examples section.
284
285This version of the program only allows one signer per message but it
286will verify multiple signers on received messages. Some S/MIME clients
287choke if a message contains multiple signers. It is possible to sign
288messages "in parallel" by signing an already signed message.
289
290The options B<-encrypt> and B<-decrypt> reflect common usage in S/MIME
291clients. Strictly speaking these process PKCS#7 enveloped data: PKCS#7
292encrypted data is used for other purposes.
293
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294The B<-resign> option uses an existing message digest when adding a new
295signer. This means that attributes must be present in at least one existing
296signer using the same message digest or this operation will fail.
297
298The B<-stream> and B<-indef> options enable experimental streaming I/O support.
299As a result the encoding is BER using indefinite length constructed encoding
300and no longer DER. Streaming is supported for the B<-encrypt> operation and the
301B<-sign> operation if the content is not detached.
302
303Streaming is always used for the B<-sign> operation with detached data but
304since the content is no longer part of the PKCS#7 structure the encoding
305remains DER.
306
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307=head1 EXIT CODES
308
309=over 4
310
4bb195ec 311=item Z<>0
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312
313the operation was completely successfully.
314
4bb195ec 315=item Z<>1
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316
317an error occurred parsing the command options.
318
4bb195ec 319=item Z<>2
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320
321one of the input files could not be read.
322
4bb195ec 323=item Z<>3
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324
325an error occurred creating the PKCS#7 file or when reading the MIME
326message.
327
4bb195ec 328=item Z<>4
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329
330an error occurred decrypting or verifying the message.
331
4bb195ec 332=item Z<>5
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333
334the message was verified correctly but an error occurred writing out
335the signers certificates.
336
337=back
338
339=head1 EXAMPLES
340
341Create a cleartext signed message:
342
343 openssl smime -sign -in message.txt -text -out mail.msg \
344 -signer mycert.pem
345
9f1859dd 346Create an opaque signed message:
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347
348 openssl smime -sign -in message.txt -text -out mail.msg -nodetach \
349 -signer mycert.pem
350
351Create a signed message, include some additional certificates and
352read the private key from another file:
353
354 openssl smime -sign -in in.txt -text -out mail.msg \
355 -signer mycert.pem -inkey mykey.pem -certfile mycerts.pem
356
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357Create a signed message with two signers:
358
359 openssl smime -sign -in message.txt -text -out mail.msg \
360 -signer mycert.pem -signer othercert.pem
361
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362Send a signed message under Unix directly to sendmail, including headers:
363
364 openssl smime -sign -in in.txt -text -signer mycert.pem \
365 -from steve@openssl.org -to someone@somewhere \
366 -subject "Signed message" | sendmail someone@somewhere
367
368Verify a message and extract the signer's certificate if successful:
369
370 openssl smime -verify -in mail.msg -signer user.pem -out signedtext.txt
371
372Send encrypted mail using triple DES:
373
374 openssl smime -encrypt -in in.txt -from steve@openssl.org \
375 -to someone@somewhere -subject "Encrypted message" \
376 -des3 user.pem -out mail.msg
377
378Sign and encrypt mail:
379
380 openssl smime -sign -in ml.txt -signer my.pem -text \
381 | openssl smime -encrypt -out mail.msg \
382 -from steve@openssl.org -to someone@somewhere \
383 -subject "Signed and Encrypted message" -des3 user.pem
384
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385Note: the encryption command does not include the B<-text> option because the
386message being encrypted already has MIME headers.
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387
388Decrypt mail:
389
390 openssl smime -decrypt -in mail.msg -recip mycert.pem -inkey key.pem
391
392The output from Netscape form signing is a PKCS#7 structure with the
393detached signature format. You can use this program to verify the
394signature by line wrapping the base64 encoded structure and surrounding
395it with:
396
397 -----BEGIN PKCS7-----
398 -----END PKCS7-----
399
9f1859dd 400and using the command:
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401
402 openssl smime -verify -inform PEM -in signature.pem -content content.txt
403
9f1859dd 404Alternatively you can base64 decode the signature and use:
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405
406 openssl smime -verify -inform DER -in signature.der -content content.txt
407
408Create an encrypted message using 128 bit Camellia:
409
410 openssl smime -encrypt -in plain.txt -camellia128 -out mail.msg cert.pem
411
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412Add a signer to an existing message:
413
414 openssl smime -resign -in mail.msg -signer newsign.pem -out mail2.msg
415
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416=head1 BUGS
417
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418The MIME parser isn't very clever: it seems to handle most messages that I've
419thrown at it but it may choke on others.
730b1645 420
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421The code currently will only write out the signer's certificate to a file: if
422the signer has a separate encryption certificate this must be manually
423extracted. There should be some heuristic that determines the correct
424encryption certificate.
730b1645 425
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426Ideally a database should be maintained of a certificates for each email
427address.
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428
429The code doesn't currently take note of the permitted symmetric encryption
9f1859dd 430algorithms as supplied in the SMIMECapabilities signed attribute. This means the
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431user has to manually include the correct encryption algorithm. It should store
432the list of permitted ciphers in a database and only use those.
433
434No revocation checking is done on the signer's certificate.
435
436The current code can only handle S/MIME v2 messages, the more complex S/MIME v3
437structures may cause parsing errors.
438
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439=head1 HISTORY
440
441The use of multiple B<-signer> options and the B<-resign> command were first
442added in OpenSSL 1.0.0
443
444
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