| =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 |
| |
| OpenSSL_add_all_algorithms() (or equivalent) should be called before using this |
| function or errors about unknown algorithms will occur. |
| |
| 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. |
| |
| 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)|ERR_get_error(3)>, L<CMS_encrypt(3)|CMS_encrypt(3)> |
| |
| =head1 HISTORY |
| |
| CMS_decrypt() was added to OpenSSL 0.9.8 |
| |
| =cut |
