=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 PKCS#7 structure.
L<ERR_get_error(3)>, L<PKCS7_encrypt(3)>
-=head1 HISTORY
-
-PKCS7_decrypt() was added to OpenSSL 0.9.5
-
=cut