1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
|
=pod
{- OpenSSL::safe::output_do_not_edit_headers(); -}
=head1 NAME
openssl-cms - CMS command
=head1 SYNOPSIS
B<openssl> B<cms>
[B<-help>]
[B<-encrypt>]
[B<-decrypt>]
[B<-debug_decrypt>]
[B<-sign>]
[B<-verify>]
[B<-verify_retcode>]
[B<-no_attr_verify>]
[B<-nosigs>]
[B<-no_content_verify>]
[B<-cmsout>]
[B<-resign>]
[B<-cades>]
[B<-data_create>]
[B<-data_out>]
[B<-digest_create>]
[B<-digest_verify>]
[B<-compress>]
[B<-uncompress>]
[B<-EncryptedData_decrypt>]
[B<-EncryptedData_encrypt>]
[B<-sign_receipt>]
[B<-verify_receipt> I<receipt>]
[B<-in> I<filename>]
[B<-out> I<filename>]
[B<-inform> B<DER>|B<PEM>|B<SMIME>]
[B<-outform> B<DER>|B<PEM>|B<SMIME>]
[B<-rctform> B<DER>|B<PEM>|B<SMIME>]
[B<-keyform> B<DER>|B<PEM>|B<P12>|B<ENGINE>]
[B<-stream>]
[B<-indef>]
[B<-noindef>]
[B<-content> I<filename>]
[B<-text>]
[B<-noout>]
[B<-print>]
[B<-nameopt> I<option>]
[B<-md> I<digest>]
[B<-I<cipher>>]
[B<-wrap> I<cipher>]
[B<-nointern>]
[B<-noverify>]
[B<-nocerts>]
[B<-noattr>]
[B<-nosmimecap>]
[B<-binary>]
[B<-crlfeol>]
[B<-asciicrlf>]
[B<-nodetach>]
[B<-certfile> I<file>]
[B<-certsout> I<file>]
[B<-signer> I<file>]
[B<-originator> I<file>]
[B<-recip> I<file>]
[B<-keyid>]
[B<-receipt_request_all>]
[B<-receipt_request_first>]
[B<-receipt_request_from> I<emailaddress>]
[B<-receipt_request_to> I<emailaddress>]
[B<-receipt_request_print>]
[B<-pwri_password> I<password>]
[B<-secretkey> I<key>]
[B<-secretkeyid> I<id>]
[B<-econtent_type> I<type>]
[B<-inkey> I<filename>|I<uri>]
[B<-keyopt> I<name>:I<parameter>]
[B<-passin> I<arg>]
[B<-to> I<addr>]
[B<-from> I<addr>]
[B<-subject> I<subj>]
{- $OpenSSL::safe::opt_v_synopsis -}
{- $OpenSSL::safe::opt_trust_synopsis -}
{- $OpenSSL::safe::opt_r_synopsis -}
{- $OpenSSL::safe::opt_engine_synopsis -}{- $OpenSSL::safe::opt_provider_synopsis -}
{- $OpenSSL::safe::opt_config_synopsis -}
[I<recipient-cert> ...]
=for openssl ifdef des-wrap engine
=head1 DESCRIPTION
This command handles S/MIME v3.1 mail. It can encrypt, decrypt,
sign and verify, compress and uncompress S/MIME messages.
=head1 OPTIONS
There are fourteen operation options that set the type of operation to be
performed. The meaning of the other options varies according to the operation
type.
=over 4
=item B<-help>
Print out a usage message.
=item B<-encrypt>
Encrypt mail for the given recipient certificates. Input file is the message
to be encrypted. The output file is the encrypted mail in MIME format. The
actual CMS type is B<EnvelopedData>.
Note that no revocation check is done for the recipient cert, so if that
key has been compromised, others may be able to decrypt the text.
=item B<-decrypt>
Decrypt mail using the supplied certificate and private key. Expects an
encrypted mail message in MIME format for the input file. The decrypted mail
is written to the output file.
=item B<-debug_decrypt>
This option sets the B<CMS_DEBUG_DECRYPT> flag. This option should be used
with caution: see the notes section below.
=item B<-sign>
Sign mail using the supplied certificate and private key. Input file is
the message to be signed. The signed message in MIME format is written
to the output file.
=item B<-verify>
Verify signed mail. Expects a signed mail message on input and outputs
the signed data. Both clear text and opaque signing is supported.
=item B<-verify_retcode>
Exit nonzero on verification failure.
=item B<-no_attr_verify>
Do not verify signed attribute signatures.
=item B<-no_content_verify>
Do not verify signed content signatures.
=item B<-nosigs>
Don't verify message signature.
=item B<-cmsout>
Takes an input message and writes out a PEM encoded CMS structure.
=item B<-resign>
Resign a message: take an existing message and one or more new signers.
=item B<-cades>
Add an ESS signing-certificate or ESS signing-certificate-v2 signed-attribute to the SignerInfo, in order to make
the signature comply with the requirements for a CAdES Basic Electronic Signature (CAdES-BES). See the NOTES
section for more details.
=item B<-data_create>
Create a CMS B<Data> type.
=item B<-data_out>
B<Data> type and output the content.
=item B<-digest_create>
Create a CMS B<DigestedData> type.
=item B<-digest_verify>
Verify a CMS B<DigestedData> type and output the content.
=item B<-compress>
Create a CMS B<CompressedData> type. OpenSSL must be compiled with B<zlib>
support for this option to work, otherwise it will output an error.
=item B<-uncompress>
Uncompress a CMS B<CompressedData> type and output the content. OpenSSL must be
compiled with B<zlib> support for this option to work, otherwise it will
output an error.
=item B<-EncryptedData_decrypt>
Decrypt content using supplied symmetric key and algorithm using a CMS
B<EncryptedData> type and output the content.
=item B<-EncryptedData_encrypt>
Encrypt content using supplied symmetric key and algorithm using a CMS
B<EncryptedData> type and output the content.
=item B<-sign_receipt>
Generate and output a signed receipt for the supplied message. The input
message B<must> contain a signed receipt request. Functionality is otherwise
similar to the B<-sign> operation.
=item B<-verify_receipt> I<receipt>
Verify a signed receipt in filename B<receipt>. The input message B<must>
contain the original receipt request. Functionality is otherwise similar
to the B<-verify> operation.
=item B<-in> I<filename>
The input message to be encrypted or signed or the message to be decrypted
or verified.
=item B<-out> I<filename>
The message text that has been decrypted or verified or the output MIME
format message that has been signed or verified.
=item B<-inform> B<DER>|B<PEM>|B<SMIME>
The input format of the CMS structure (if one is being read);
the default is B<SMIME>.
See L<openssl-format-options(1)> for details.
=item B<-outform> B<DER>|B<PEM>|B<SMIME>
The output format of the CMS structure (if one is being written);
the default is B<SMIME>.
See L<openssl-format-options(1)> for details.
=item B<-keyform> B<DER>|B<PEM>|B<P12>|B<ENGINE>
The format of the private key file; the default is B<PEM>.
The only value with effect is B<ENGINE>; all others have become obsolete.
See L<openssl-format-options(1)> for details.
=item B<-rctform> B<DER>|B<PEM>|B<SMIME>
The signed receipt format for use with the B<-receipt_verify>; the default
is B<SMIME>.
See L<openssl-format-options(1)> for details.
=item B<-stream>, B<-indef>
The B<-stream> and B<-indef> options are equivalent and enable streaming I/O
for encoding operations. This permits single pass processing of data without
the need to hold the entire contents in memory, potentially supporting very
large files. Streaming is automatically set for S/MIME signing with detached
data if the output format is B<SMIME> it is currently off by default for all
other operations.
=item B<-noindef>
Disable streaming I/O where it would produce and indefinite length constructed
encoding. This option currently has no effect. In future streaming will be
enabled by default on all relevant operations and this option will disable it.
=item B<-content> I<filename>
This specifies a file containing the detached content, this is only
useful with the B<-verify> command. This is only usable if the CMS
structure is using the detached signature form where the content is
not included. This option will override any content if the input format
is S/MIME and it uses the multipart/signed MIME content type.
=item B<-text>
This option adds plain text (text/plain) MIME headers to the supplied
message if encrypting or signing. If decrypting or verifying it strips
off text headers: if the decrypted or verified message is not of MIME
type text/plain then an error occurs.
=item B<-noout>
For the B<-cmsout> operation do not output the parsed CMS structure. This
is useful when combined with the B<-print> option or if the syntax of the CMS
structure is being checked.
=item B<-print>
For the B<-cmsout> operation print out all fields of the CMS structure. This
is mainly useful for testing purposes.
=item B<-nameopt> I<option>
For the B<-cmsout> operation when B<-print> option is in use, specifies
printing options for string fields. For most cases B<utf8> is reasonable value.
See L<openssl-namedisplay-options(1)> for details.
=item B<-md> I<digest>
Digest algorithm to use when signing or resigning. If not present then the
default digest algorithm for the signing key will be used (usually SHA1).
=item B<-I<cipher>>
The encryption algorithm to use. For example triple DES (168 bits) - B<-des3>
or 256 bit AES - B<-aes256>. Any standard algorithm name (as used by the
EVP_get_cipherbyname() function) can also be used preceded by a dash, for
example B<-aes-128-cbc>. See L<openssl-enc(1)> for a list of ciphers
supported by your version of OpenSSL.
Currently the AES variants with GCM mode are the only supported AEAD
algorithms.
If not specified triple DES is used. Only used with B<-encrypt> and
B<-EncryptedData_create> commands.
=item B<-wrap> I<cipher>
Cipher algorithm to use for key wrap when encrypting the message using Key
Agreement for key transport. The algorithm specified should be suitable for key
wrap.
=item B<-nointern>
When verifying a message normally certificates (if any) included in
the message are searched for the signing certificate. With this option
only the certificates specified in the B<-certfile> option are used.
The supplied certificates can still be used as untrusted CAs however.
=item B<-noverify>
Do not verify the signers certificate of a signed message.
=item B<-nocerts>
When signing a message the signer's certificate is normally included
with this option it is excluded. This will reduce the size of the
signed message but the verifier must have a copy of the signers certificate
available locally (passed using the B<-certfile> option for example).
=item B<-noattr>
Normally when a message is signed a set of attributes are included which
include the signing time and supported symmetric algorithms. With this
option they are not included.
=item B<-nosmimecap>
Exclude the list of supported algorithms from signed attributes, other options
such as signing time and content type are still included.
=item B<-binary>
Normally the input message is converted to "canonical" format which is
effectively using CR and LF as end of line: as required by the S/MIME
specification. When this option is present no translation occurs. This
is useful when handling binary data which may not be in MIME format.
=item B<-crlfeol>
Normally the output file uses a single B<LF> as end of line. When this
option is present B<CRLF> is used instead.
=item B<-asciicrlf>
When signing use ASCII CRLF format canonicalisation. This strips trailing
whitespace from all lines, deletes trailing blank lines at EOF and sets
the encapsulated content type. This option is normally used with detached
content and an output signature format of DER. This option is not normally
needed when verifying as it is enabled automatically if the encapsulated
content format is detected.
=item B<-nodetach>
When signing a message use opaque signing: this form is more resistant
to translation by mail relays but it cannot be read by mail agents that
do not support S/MIME. Without this option cleartext signing with
the MIME type multipart/signed is used.
=item B<-certfile> I<file>
Allows additional certificates to be specified. When signing these will
be included with the message. When verifying these will be searched for
the signers certificates.
The input can be in PEM, DER, or PKCS#12 format.
=item B<-certsout> I<file>
Any certificates contained in the message are written to I<file>.
=item B<-signer> I<file>
A signing certificate when signing or resigning a message, this option can be
used multiple times if more than one signer is required. If a message is being
verified then the signers certificates will be written to this file if the
verification was successful.
=item B<-originator> I<file>
A certificate of the originator of the encrypted message. Necessary for
decryption when Key Agreement is in use for a shared key.
=item B<-recip> I<file>
When decrypting a message this specifies the recipients certificate. The
certificate must match one of the recipients of the message or an error
occurs.
When encrypting a message this option may be used multiple times to specify
each recipient. This form B<must> be used if customised parameters are
required (for example to specify RSA-OAEP).
Only certificates carrying RSA, Diffie-Hellman or EC keys are supported by this
option.
=item B<-keyid>
Use subject key identifier to identify certificates instead of issuer name and
serial number. The supplied certificate B<must> include a subject key
identifier extension. Supported by B<-sign> and B<-encrypt> options.
=item B<-receipt_request_all>, B<-receipt_request_first>
For B<-sign> option include a signed receipt request. Indicate requests should
be provided by all recipient or first tier recipients (those mailed directly
and not from a mailing list). Ignored it B<-receipt_request_from> is included.
=item B<-receipt_request_from> I<emailaddress>
For B<-sign> option include a signed receipt request. Add an explicit email
address where receipts should be supplied.
=item B<-receipt_request_to> I<emailaddress>
Add an explicit email address where signed receipts should be sent to. This
option B<must> but supplied if a signed receipt it requested.
=item B<-receipt_request_print>
For the B<-verify> operation print out the contents of any signed receipt
requests.
=item B<-pwri_password> I<password>
Specify password for recipient.
=item B<-secretkey> I<key>
Specify symmetric key to use. The key must be supplied in hex format and be
consistent with the algorithm used. Supported by the B<-EncryptedData_encrypt>
B<-EncryptedData_decrypt>, B<-encrypt> and B<-decrypt> options. When used
with B<-encrypt> or B<-decrypt> the supplied key is used to wrap or unwrap the
content encryption key using an AES key in the B<KEKRecipientInfo> type.
=item B<-secretkeyid> I<id>
The key identifier for the supplied symmetric key for B<KEKRecipientInfo> type.
This option B<must> be present if the B<-secretkey> option is used with
B<-encrypt>. With B<-decrypt> operations the I<id> is used to locate the
relevant key if it is not supplied then an attempt is used to decrypt any
B<KEKRecipientInfo> structures.
=item B<-econtent_type> I<type>
Set the encapsulated content type to I<type> if not supplied the B<Data> type
is used. The I<type> argument can be any valid OID name in either text or
numerical format.
=item B<-inkey> I<filename>|I<uri>
The private key to use when signing or decrypting. This must match the
corresponding certificate. If this option is not specified then the
private key must be included in the certificate file specified with
the B<-recip> or B<-signer> file. When signing this option can be used
multiple times to specify successive keys.
=item B<-keyopt> I<name>:I<parameter>
For signing and encryption this option can be used multiple times to
set customised parameters for the preceding key or certificate. It can
currently be used to set RSA-PSS for signing, RSA-OAEP for encryption
or to modify default parameters for ECDH.
=item B<-passin> I<arg>
The private key password source. For more information about the format of B<arg>
see L<openssl-passphrase-options(1)>.
=item B<-to>, B<-from>, B<-subject>
The relevant mail headers. These are included outside the signed
portion of a message so they may be included manually. If signing
then many S/MIME mail clients check the signers certificate's email
address matches that specified in the From: address.
{- $OpenSSL::safe::opt_v_item -}
Any verification errors cause the command to exit.
{- $OpenSSL::safe::opt_trust_item -}
{- $OpenSSL::safe::opt_r_item -}
{- $OpenSSL::safe::opt_engine_item -}
{- $OpenSSL::safe::opt_provider_item -}
{- $OpenSSL::safe::opt_config_item -}
=item I<recipient-cert> ...
One or more certificates of message recipients: used when encrypting
a message.
=back
=head1 NOTES
The MIME message must be sent without any blank lines between the
headers and the output. Some mail programs will automatically add
a blank line. Piping the mail directly to sendmail is one way to
achieve the correct format.
The supplied message to be signed or encrypted must include the
necessary MIME headers or many S/MIME clients won't display it
properly (if at all). You can use the B<-text> option to automatically
add plain text headers.
A "signed and encrypted" message is one where a signed message is
then encrypted. This can be produced by encrypting an already signed
message: see the examples section.
This version of the program only allows one signer per message but it
will verify multiple signers on received messages. Some S/MIME clients
choke if a message contains multiple signers. It is possible to sign
messages "in parallel" by signing an already signed message.
The options B<-encrypt> and B<-decrypt> reflect common usage in S/MIME
clients. Strictly speaking these process CMS enveloped data: CMS
encrypted data is used for other purposes.
The B<-resign> option uses an existing message digest when adding a new
signer. This means that attributes must be present in at least one existing
signer using the same message digest or this operation will fail.
The B<-stream> and B<-indef> options enable streaming I/O support.
As a result the encoding is BER using indefinite length constructed encoding
and no longer DER. Streaming is supported for the B<-encrypt> operation and the
B<-sign> operation if the content is not detached.
Streaming is always used for the B<-sign> operation with detached data but
since the content is no longer part of the CMS structure the encoding
remains DER.
If the B<-decrypt> option is used without a recipient certificate then an
attempt is made to locate the recipient by trying each potential recipient
in turn using the supplied private key. To thwart the MMA attack
(Bleichenbacher's attack on PKCS #1 v1.5 RSA padding) all recipients are
tried whether they succeed or not and if no recipients match the message
is "decrypted" using a random key which will typically output garbage.
The B<-debug_decrypt> option can be used to disable the MMA attack protection
and return an error if no recipient can be found: this option should be used
with caution. For a fuller description see L<CMS_decrypt(3)>).
=head1 CADES BASIC ELECTRONIC SIGNATURE (CADES-BES)
A CAdES Basic Electronic Signature (CAdES-BES), as defined in the European Standard ETSI EN 319 122-1 V1.1.1, contains:
=over 4
=item *
The signed user data as defined in CMS (RFC 3852);
=item *
Content-type of the EncapsulatedContentInfo value being signed;
=item *
Message-digest of the eContent OCTET STRING within encapContentInfo being signed;
=item *
An ESS signing-certificate or ESS signing-certificate-v2 attribute, as defined
in Enhanced Security Services (ESS), RFC 2634 and RFC 5035.
An ESS signing-certificate attribute only allows for the use of SHA-1 as a digest algorithm.
An ESS signing-certificate-v2 attribute allows for the use of any digest algorithm.
=item *
The digital signature value computed on the user data and, when present, on the signed attributes.
NOTE that the B<-cades> option applies to the B<-sign> or B<-verify> operations.
With this option, the B<-verify> operation also checks that the signing-certificates
attribute is present, and its value matches the verification trust chain built
during the verification process.
=back
=head1 EXIT CODES
=over 4
=item Z<>0
The operation was completely successfully.
=item Z<>1
An error occurred parsing the command options.
=item Z<>2
One of the input files could not be read.
=item Z<>3
An error occurred creating the CMS file or when reading the MIME
message.
=item Z<>4
An error occurred decrypting or verifying the message.
=item Z<>5
The message was verified correctly but an error occurred writing out
the signers certificates.
=back
=head1 COMPATIBILITY WITH PKCS#7 FORMAT
L<openssl-smime(1)> can only process the older B<PKCS#7> format.
B<openssl cms> supports Cryptographic Message Syntax format.
Use of some features will result in messages which cannot be processed by
applications which only support the older format. These are detailed below.
The use of the B<-keyid> option with B<-sign> or B<-encrypt>.
The B<-outform> I<PEM> option uses different headers.
The B<-compress> option.
The B<-secretkey> option when used with B<-encrypt>.
The use of PSS with B<-sign>.
The use of OAEP or non-RSA keys with B<-encrypt>.
Additionally the B<-EncryptedData_create> and B<-data_create> type cannot
be processed by the older L<openssl-smime(1)> command.
=head1 EXAMPLES
Create a cleartext signed message:
openssl cms -sign -in message.txt -text -out mail.msg \
-signer mycert.pem
Create an opaque signed message
openssl cms -sign -in message.txt -text -out mail.msg -nodetach \
-signer mycert.pem
Create a signed message, include some additional certificates and
read the private key from another file:
openssl cms -sign -in in.txt -text -out mail.msg \
-signer mycert.pem -inkey mykey.pem -certfile mycerts.pem
Create a signed message with two signers, use key identifier:
openssl cms -sign -in message.txt -text -out mail.msg \
-signer mycert.pem -signer othercert.pem -keyid
Send a signed message under Unix directly to sendmail, including headers:
openssl cms -sign -in in.txt -text -signer mycert.pem \
-from steve@openssl.org -to someone@somewhere \
-subject "Signed message" | sendmail someone@somewhere
Verify a message and extract the signer's certificate if successful:
openssl cms -verify -in mail.msg -signer user.pem -out signedtext.txt
Send encrypted mail using triple DES:
openssl cms -encrypt -in in.txt -from steve@openssl.org \
-to someone@somewhere -subject "Encrypted message" \
-des3 user.pem -out mail.msg
Sign and encrypt mail:
openssl cms -sign -in ml.txt -signer my.pem -text \
| openssl cms -encrypt -out mail.msg \
-from steve@openssl.org -to someone@somewhere \
-subject "Signed and Encrypted message" -des3 user.pem
Note: the encryption command does not include the B<-text> option because the
message being encrypted already has MIME headers.
Decrypt mail:
openssl cms -decrypt -in mail.msg -recip mycert.pem -inkey key.pem
The output from Netscape form signing is a PKCS#7 structure with the
detached signature format. You can use this program to verify the
signature by line wrapping the base64 encoded structure and surrounding
it with:
-----BEGIN PKCS7-----
-----END PKCS7-----
and using the command,
openssl cms -verify -inform PEM -in signature.pem -content content.txt
alternatively you can base64 decode the signature and use
openssl cms -verify -inform DER -in signature.der -content content.txt
Create an encrypted message using 128 bit Camellia:
openssl cms -encrypt -in plain.txt -camellia128 -out mail.msg cert.pem
Add a signer to an existing message:
openssl cms -resign -in mail.msg -signer newsign.pem -out mail2.msg
Sign mail using RSA-PSS:
openssl cms -sign -in message.txt -text -out mail.msg \
-signer mycert.pem -keyopt rsa_padding_mode:pss
Create encrypted mail using RSA-OAEP:
openssl cms -encrypt -in plain.txt -out mail.msg \
-recip cert.pem -keyopt rsa_padding_mode:oaep
Use SHA256 KDF with an ECDH certificate:
openssl cms -encrypt -in plain.txt -out mail.msg \
-recip ecdhcert.pem -keyopt ecdh_kdf_md:sha256
=head1 BUGS
The MIME parser isn't very clever: it seems to handle most messages that I've
thrown at it but it may choke on others.
The code currently will only write out the signer's certificate to a file: if
the signer has a separate encryption certificate this must be manually
extracted. There should be some heuristic that determines the correct
encryption certificate.
Ideally a database should be maintained of a certificates for each email
address.
The code doesn't currently take note of the permitted symmetric encryption
algorithms as supplied in the SMIMECapabilities signed attribute. this means the
user has to manually include the correct encryption algorithm. It should store
the list of permitted ciphers in a database and only use those.
No revocation checking is done on the signer's certificate.
=head1 SEE ALSO
L<ossl_store-file(7)>
=head1 HISTORY
The use of multiple B<-signer> options and the B<-resign> command were first
added in OpenSSL 1.0.0.
The B<-keyopt> option was added in OpenSSL 1.0.2.
Support for RSA-OAEP and RSA-PSS was added in OpenSSL 1.0.2.
The use of non-RSA keys with B<-encrypt> and B<-decrypt>
was added in OpenSSL 1.0.2.
The -no_alt_chains option was added in OpenSSL 1.0.2b.
All B<-keyform> values except B<ENGINE> have become obsolete in OpenSSL 3.0.0
and have no effect.
The B<-nameopt> option was added in OpenSSL 3.0.0.
The B<-engine> option was deprecated in OpenSSL 3.0.
=head1 COPYRIGHT
Copyright 2008-2020 The OpenSSL Project Authors. All Rights Reserved.
Licensed under the Apache License 2.0 (the "License"). You may not use
this file except in compliance with the License. You can obtain a copy
in the file LICENSE in the source distribution or at
L<https://www.openssl.org/source/license.html>.
=cut
|