diff options
Diffstat (limited to 'doc/crypto/CMS_decrypt.pod')
| -rw-r--r-- | doc/crypto/CMS_decrypt.pod | 81 |
1 files changed, 0 insertions, 81 deletions
diff --git a/doc/crypto/CMS_decrypt.pod b/doc/crypto/CMS_decrypt.pod deleted file mode 100644 index b3b196c390..0000000000 --- a/doc/crypto/CMS_decrypt.pod +++ /dev/null @@ -1,81 +0,0 @@ -=pod - -=head1 NAME - -CMS_decrypt - 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); - -=head1 DESCRIPTION - -CMS_decrypt() extracts and decrypts the content from a CMS EnvelopedData -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. - -=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_ReceipientInfo_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 COPYRIGHT - -Copyright 2008-2016 The OpenSSL Project Authors. All Rights Reserved. - -Licensed under the OpenSSL license (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 |