1OPENSSL-SMIME(1ossl) OpenSSL OPENSSL-SMIME(1ossl)
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6 openssl-smime - S/MIME command
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9 openssl smime [-help] [-encrypt] [-decrypt] [-sign] [-resign] [-verify]
10 [-pk7out] [-binary] [-crlfeol] [-cipher] [-in file] [-certfile file]
11 [-signer file] [-nointern] [-noverify] [-nochain] [-nosigs] [-nocerts]
12 [-noattr] [-nodetach] [-nosmimecap] [-recip file] [-inform
13 DER|PEM|SMIME] [-outform DER|PEM|SMIME] [-keyform DER|PEM|P12|ENGINE]
14 [-passin arg] [-inkey filename|uri] [-out file] [-content file] [-to
15 addr] [-from ad] [-subject s] [-text] [-indef] [-noindef] [-stream]
16 [-md digest] [-CAfile file] [-no-CAfile] [-CApath dir] [-no-CApath]
17 [-CAstore uri] [-no-CAstore] [-engine id] [-rand files] [-writerand
18 file] [-allow_proxy_certs] [-attime timestamp] [-no_check_time]
19 [-check_ss_sig] [-crl_check] [-crl_check_all] [-explicit_policy]
20 [-extended_crl] [-ignore_critical] [-inhibit_any] [-inhibit_map]
21 [-partial_chain] [-policy arg] [-policy_check] [-policy_print]
22 [-purpose purpose] [-suiteB_128] [-suiteB_128_only] [-suiteB_192]
23 [-trusted_first] [-no_alt_chains] [-use_deltas] [-auth_level num]
24 [-verify_depth num] [-verify_email email] [-verify_hostname hostname]
25 [-verify_ip ip] [-verify_name name] [-x509_strict] [-issuer_checks]
26 [-provider name] [-provider-path path] [-propquery propq] [-config
27 configfile] recipcert ...
28
30 This command handles S/MIME mail. It can encrypt, decrypt, sign and
31 verify S/MIME messages.
32
34 There are six operation options that set the type of operation to be
35 performed. The meaning of the other options varies according to the
36 operation type.
37 -help
39 Print out a usage message.
40 -encrypt
42 Encrypt mail for the given recipient certificates. Input file is
43 the message to be encrypted. The output file is the encrypted mail
44 in MIME format.
45 Note that no revocation check is done for the recipient cert, so if
47 that key has been compromised, others may be able to decrypt the
48 text.
49 -decrypt
51 Decrypt mail using the supplied certificate and private key.
52 Expects an encrypted mail message in MIME format for the input
53 file. The decrypted mail is written to the output file.
54 -sign
56 Sign mail using the supplied certificate and private key. Input
57 file is the message to be signed. The signed message in MIME format
58 is written to the output file.
59 -verify
61 Verify signed mail. Expects a signed mail message on input and
62 outputs the signed data. Both clear text and opaque signing is
63 supported.
64 -pk7out
66 Takes an input message and writes out a PEM encoded PKCS#7
67 structure.
68 -resign
70 Resign a message: take an existing message and one or more new
71 signers.
72 -in filename
74 The input message to be encrypted or signed or the MIME message to
75 be decrypted or verified.
76 -out filename
78 The message text that has been decrypted or verified or the output
79 MIME format message that has been signed or verified.
80 -inform DER|PEM|SMIME
82 The input format of the PKCS#7 (S/MIME) structure (if one is being
83 read); the default is SMIME. See openssl-format-options(1) for
84 details.
85 -outform DER|PEM|SMIME
87 The output format of the PKCS#7 (S/MIME) structure (if one is being
88 written); the default is SMIME. See openssl-format-options(1) for
89 details.
90 -keyform DER|PEM|P12|ENGINE
92 The key format; unspecified by default. See
93 openssl-format-options(1) for details.
94 -stream, -indef, -noindef
96 The -stream and -indef options are equivalent and enable streaming
97 I/O for encoding operations. This permits single pass processing of
98 data without the need to hold the entire contents in memory,
99 potentially supporting very large files. Streaming is automatically
100 set for S/MIME signing with detached data if the output format is
101 SMIME it is currently off by default for all other operations.
102 -noindef
104 Disable streaming I/O where it would produce and indefinite length
105 constructed encoding. This option currently has no effect. In
106 future streaming will be enabled by default on all relevant
107 operations and this option will disable it.
108 -content filename
110 This specifies a file containing the detached content, this is only
111 useful with the -verify command. This is only usable if the PKCS#7
112 structure is using the detached signature form where the content is
113 not included. This option will override any content if the input
114 format is S/MIME and it uses the multipart/signed MIME content
115 type.
116 -text
118 This option adds plain text (text/plain) MIME headers to the
119 supplied message if encrypting or signing. If decrypting or
120 verifying it strips off text headers: if the decrypted or verified
121 message is not of MIME type text/plain then an error occurs.
122 -md digest
124 Digest algorithm to use when signing or resigning. If not present
125 then the default digest algorithm for the signing key will be used
126 (usually SHA1).
127 -cipher
129 The encryption algorithm to use. For example DES (56 bits) - -des,
130 triple DES (168 bits) - -des3, EVP_get_cipherbyname() function) can
131 also be used preceded by a dash, for example -aes-128-cbc. See
132 openssl-enc(1) for list of ciphers supported by your version of
133 OpenSSL.
134 If not specified triple DES is used. Only used with -encrypt.
136 -nointern
138 When verifying a message normally certificates (if any) included in
139 the message are searched for the signing certificate. With this
140 option only the certificates specified in the -certfile option are
141 used. The supplied certificates can still be used as untrusted CAs
142 however.
143 -noverify
145 Do not verify the signers certificate of a signed message.
146 -nochain
148 Do not do chain verification of signers certificates; that is, do
149 not use the certificates in the signed message as untrusted CAs.
150 -nosigs
152 Don't try to verify the signatures on the message.
153 -nocerts
155 When signing a message the signer's certificate is normally
156 included with this option it is excluded. This will reduce the size
157 of the signed message but the verifier must have a copy of the
158 signers certificate available locally (passed using the -certfile
159 option for example).
160 -noattr
162 Normally when a message is signed a set of attributes are included
163 which include the signing time and supported symmetric algorithms.
164 With this option they are not included.
165 -nodetach
167 When signing a message use opaque signing. This form is more
168 resistant to translation by mail relays but it cannot be read by
169 mail agents that do not support S/MIME. Without this option
170 cleartext signing with the MIME type multipart/signed is used.
171 -nosmimecap
173 When signing a message, do not include the SMIMECapabilities
174 attribute.
175 -binary
177 Normally the input message is converted to "canonical" format which
178 is effectively using CR and LF as end of line: as required by the
179 S/MIME specification. When this option is present no translation
180 occurs. This is useful when handling binary data which may not be
181 in MIME format.
182 -crlfeol
184 Normally the output file uses a single LF as end of line. When this
185 option is present CRLF is used instead.
186 -certfile file
188 Allows additional certificates to be specified. When signing these
189 will be included with the message. When verifying these will be
190 searched for the signers certificates. The input can be in PEM,
191 DER, or PKCS#12 format.
192 -signer file
194 A signing certificate when signing or resigning a message, this
195 option can be used multiple times if more than one signer is
196 required. If a message is being verified then the signers
197 certificates will be written to this file if the verification was
198 successful.
199 -nocerts
201 Don't include signers certificate when signing.
202 -noattr
204 Don't include any signed attributes when signing.
205 -recip file
207 The recipients certificate when decrypting a message. This
208 certificate must match one of the recipients of the message or an
209 error occurs.
210 -inkey filename|uri
212 The private key to use when signing or decrypting. This must match
213 the corresponding certificate. If this option is not specified then
214 the private key must be included in the certificate file specified
215 with the -recip or -signer file. When signing this option can be
216 used multiple times to specify successive keys.
217 -passin arg
219 The private key password source. For more information about the
220 format of arg see openssl-passphrase-options(1).
221 -to, -from, -subject
223 The relevant mail headers. These are included outside the signed
224 portion of a message so they may be included manually. If signing
225 then many S/MIME mail clients check the signers certificate's email
226 address matches that specified in the From: address.
227 -allow_proxy_certs, -attime, -no_check_time, -check_ss_sig, -crl_check,
229 -crl_check_all, -explicit_policy, -extended_crl, -ignore_critical,
230 -inhibit_any, -inhibit_map, -no_alt_chains, -partial_chain, -policy,
231 -policy_check, -policy_print, -purpose, -suiteB_128, -suiteB_128_only,
232 -suiteB_192, -trusted_first, -use_deltas, -auth_level, -verify_depth,
233 -verify_email, -verify_hostname, -verify_ip, -verify_name, -x509_strict
234 -issuer_checks
235 Set various options of certificate chain verification. See
236 "Verification Options" in openssl-verification-options(1) for
237 details.
238 Any verification errors cause the command to exit.
240 -CAfile file, -no-CAfile, -CApath dir, -no-CApath, -CAstore uri,
242 -no-CAstore
243 See "Trusted Certificate Options" in
244 openssl-verification-options(1) for details.
245 -engine id
247 See "Engine Options" in openssl(1). This option is deprecated.
248 -rand files, -writerand file
250 See "Random State Options" in openssl(1) for details.
251 -provider name
253 -provider-path path
254 -propquery propq
255 See "Provider Options" in openssl(1), provider(7), and property(7).
256 -config configfile
258 See "Configuration Option" in openssl(1).
259 recipcert ...
261 One or more certificates of message recipients, used when
262 encrypting a message.
263
265 The MIME message must be sent without any blank lines between the
266 headers and the output. Some mail programs will automatically add a
267 blank line. Piping the mail directly to sendmail is one way to achieve
268 the correct format.
269 The supplied message to be signed or encrypted must include the
271 necessary MIME headers or many S/MIME clients won't display it properly
272 (if at all). You can use the -text option to automatically add plain
273 text headers.
274 A "signed and encrypted" message is one where a signed message is then
276 encrypted. This can be produced by encrypting an already signed
277 message: see the examples section.
278 This version of the program only allows one signer per message but it
280 will verify multiple signers on received messages. Some S/MIME clients
281 choke if a message contains multiple signers. It is possible to sign
282 messages "in parallel" by signing an already signed message.
283 The options -encrypt and -decrypt reflect common usage in S/MIME
285 clients. Strictly speaking these process PKCS#7 enveloped data: PKCS#7
286 encrypted data is used for other purposes.
287 The -resign option uses an existing message digest when adding a new
289 signer. This means that attributes must be present in at least one
290 existing signer using the same message digest or this operation will
291 fail.
292 The -stream and -indef options enable streaming I/O support. As a
294 result the encoding is BER using indefinite length constructed encoding
295 and no longer DER. Streaming is supported for the -encrypt operation
296 and the -sign operation if the content is not detached.
297 Streaming is always used for the -sign operation with detached data but
299 since the content is no longer part of the PKCS#7 structure the
300 encoding remains DER.
301
303 0 The operation was completely successfully.
304 1 An error occurred parsing the command options.
306 2 One of the input files could not be read.
308 3 An error occurred creating the PKCS#7 file or when reading the MIME
310 message.
311 4 An error occurred decrypting or verifying the message.
313 5 The message was verified correctly but an error occurred writing
315 out the signers certificates.
316
318 Create a cleartext signed message:
319 openssl smime -sign -in message.txt -text -out mail.msg \
321 -signer mycert.pem
322 Create an opaque signed message:
324 openssl smime -sign -in message.txt -text -out mail.msg -nodetach \
326 -signer mycert.pem
327 Create a signed message, include some additional certificates and read
329 the private key from another file:
330 openssl smime -sign -in in.txt -text -out mail.msg \
332 -signer mycert.pem -inkey mykey.pem -certfile mycerts.pem
333 Create a signed message with two signers:
335 openssl smime -sign -in message.txt -text -out mail.msg \
337 -signer mycert.pem -signer othercert.pem
338 Send a signed message under Unix directly to sendmail, including
340 headers:
341 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
345 Verify a message and extract the signer's certificate if successful:
347 openssl smime -verify -in mail.msg -signer user.pem -out signedtext.txt
349 Send encrypted mail using triple DES:
351 openssl smime -encrypt -in in.txt -from steve@openssl.org \
353 -to someone@somewhere -subject "Encrypted message" \
354 -des3 user.pem -out mail.msg
355 Sign and encrypt mail:
357 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
362 Note: the encryption command does not include the -text option because
364 the message being encrypted already has MIME headers.
365 Decrypt mail:
367 openssl smime -decrypt -in mail.msg -recip mycert.pem -inkey key.pem
369 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
373 it with:
374 -----BEGIN PKCS7-----
376 -----END PKCS7-----
377 and using the command:
379 openssl smime -verify -inform PEM -in signature.pem -content content.txt
381 Alternatively you can base64 decode the signature and use:
383 openssl smime -verify -inform DER -in signature.der -content content.txt
385 Create an encrypted message using 128 bit Camellia:
387 openssl smime -encrypt -in plain.txt -camellia128 -out mail.msg cert.pem
389 Add a signer to an existing message:
391 openssl smime -resign -in mail.msg -signer newsign.pem -out mail2.msg
393
395 The MIME parser isn't very clever: it seems to handle most messages
396 that I've thrown at it but it may choke on others.
397 The code currently will only write out the signer's certificate to a
399 file: if the signer has a separate encryption certificate this must be
400 manually extracted. There should be some heuristic that determines the
401 correct encryption certificate.
402 Ideally a database should be maintained of a certificates for each
404 email address.
405 The code doesn't currently take note of the permitted symmetric
407 encryption algorithms as supplied in the SMIMECapabilities signed
408 attribute. This means the user has to manually include the correct
409 encryption algorithm. It should store the list of permitted ciphers in
410 a database and only use those.
411 No revocation checking is done on the signer's certificate.
413 The current code can only handle S/MIME v2 messages, the more complex
415 S/MIME v3 structures may cause parsing errors.
416
418 ossl_store-file(7)
419
421 The use of multiple -signer options and the -resign command were first
422 added in OpenSSL 1.0.0
423 The -no_alt_chains option was added in OpenSSL 1.1.0.
425 The -engine option was deprecated in OpenSSL 3.0.
427
429 Copyright 2000-2021 The OpenSSL Project Authors. All Rights Reserved.
430 Licensed under the Apache License 2.0 (the "License"). You may not use
432 this file except in compliance with the License. You can obtain a copy
433 in the file LICENSE in the source distribution or at
434 <https://www.openssl.org/source/license.html>.
4353.1.1 2023-08-31 OPENSSL-SMIME(1ossl)