mirror of
https://github.com/openssl/openssl.git
synced 2024-12-15 06:01:37 +08:00
924663c36d
Add the AuthEnvelopedData as defined in RFC 5083 with AES-GCM parameter as defined in RFC 5084. Reviewed-by: Shane Lontis <shane.lontis@oracle.com> Reviewed-by: Tomas Mraz <tmraz@fedoraproject.org> (Merged from https://github.com/openssl/openssl/pull/8024)
98 lines
3.7 KiB
Plaintext
98 lines
3.7 KiB
Plaintext
=pod
|
|
|
|
=head1 NAME
|
|
|
|
CMS_decrypt, CMS_decrypt_set1_pkey_and_peer, CMS_decrypt_set1_pkey - decrypt
|
|
content from a CMS envelopedData structure
|
|
|
|
=head1 SYNOPSIS
|
|
|
|
#include <openssl/cms.h>
|
|
|
|
int CMS_decrypt(CMS_ContentInfo *cms, EVP_PKEY *pkey, X509 *cert,
|
|
BIO *dcont, BIO *out, unsigned int flags);
|
|
int CMS_decrypt_set1_pkey_and_peer(CMS_ContentInfo *cms,
|
|
EVP_PKEY *pk, X509 *cert, X509 *peer);
|
|
int CMS_decrypt_set1_pkey(CMS_ContentInfo *cms, EVP_PKEY *pk, X509 *cert);
|
|
|
|
=head1 DESCRIPTION
|
|
|
|
CMS_decrypt() extracts and decrypts the content from a CMS EnvelopedData
|
|
or AuthEnvelopedData structure. B<pkey> is the private key of the recipient,
|
|
B<cert> is the recipient's certificate, B<out> is a BIO to write the content to
|
|
and B<flags> is an optional set of flags.
|
|
|
|
The B<dcont> parameter is used in the rare case where the encrypted content
|
|
is detached. It will normally be set to NULL.
|
|
|
|
CMS_decrypt_set1_pkey_and_peer() associates the private key B<pkey>, the
|
|
corresponding certificate B<cert> and the originator certificate B<peer> with
|
|
the CMS_ContentInfo structure B<cms>.
|
|
|
|
CMS_decrypt_set1_pkey() associates the private key B<pkey>, corresponding
|
|
certificate B<cert> with the CMS_ContentInfo structure B<cms>.
|
|
|
|
=head1 NOTES
|
|
|
|
Although the recipients certificate is not needed to decrypt the data it is
|
|
needed to locate the appropriate (of possible several) recipients in the CMS
|
|
structure.
|
|
|
|
If B<cert> is set to NULL all possible recipients are tried. This case however
|
|
is problematic. To thwart the MMA attack (Bleichenbacher's attack on
|
|
PKCS #1 v1.5 RSA padding) all recipients are tried whether they succeed or
|
|
not. If no recipient succeeds then a random symmetric key is used to decrypt
|
|
the content: this will typically output garbage and may (but is not guaranteed
|
|
to) ultimately return a padding error only. If CMS_decrypt() just returned an
|
|
error when all recipient encrypted keys failed to decrypt an attacker could
|
|
use this in a timing attack. If the special flag B<CMS_DEBUG_DECRYPT> is set
|
|
then the above behaviour is modified and an error B<is> returned if no
|
|
recipient encrypted key can be decrypted B<without> generating a random
|
|
content encryption key. Applications should use this flag with
|
|
B<extreme caution> especially in automated gateways as it can leave them
|
|
open to attack.
|
|
|
|
It is possible to determine the correct recipient key by other means (for
|
|
example looking them up in a database) and setting them in the CMS structure
|
|
in advance using the CMS utility functions such as CMS_set1_pkey(). In this
|
|
case both B<cert> and B<pkey> should be set to NULL.
|
|
|
|
To process KEKRecipientInfo types CMS_set1_key() or CMS_RecipientInfo_set0_key()
|
|
and CMS_RecipientInfo_decrypt() should be called before CMS_decrypt() and
|
|
B<cert> and B<pkey> set to NULL.
|
|
|
|
The following flags can be passed in the B<flags> parameter.
|
|
|
|
If the B<CMS_TEXT> flag is set MIME headers for type B<text/plain> are deleted
|
|
from the content. If the content is not of type B<text/plain> then an error is
|
|
returned.
|
|
|
|
=head1 RETURN VALUES
|
|
|
|
CMS_decrypt() returns either 1 for success or 0 for failure.
|
|
The error can be obtained from ERR_get_error(3)
|
|
|
|
=head1 BUGS
|
|
|
|
The lack of single pass processing and the need to hold all data in memory as
|
|
mentioned in CMS_verify() also applies to CMS_decrypt().
|
|
|
|
=head1 SEE ALSO
|
|
|
|
L<ERR_get_error(3)>, L<CMS_encrypt(3)>
|
|
|
|
=head1 HISTORY
|
|
|
|
B<CMS_decrypt_set1_pkey_and_peer> was added 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
|