=pod =head1 NAME CMS_decrypt - decrypt content from a CMS envelopedData structure =head1 SYNOPSIS #include int CMS_decrypt(CMS_ContentInfo *cms, EVP_PKEY *pkey, X509 *cert, BIO *data, BIO *dcont, unsigned int flags); =head1 DESCRIPTION CMS_decrypt() extracts and decrypts the content from a CMS envelopedData structure. B is the private key of the recipient, B is the recipients certificate, B is a BIO to write the content to and B is an optional set of flags. The B 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 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 settin them in the CMS strutucre in advance using the CMS utility functions such as CMS_set1_pkey(). In this case both B and B should be set to NULL. To process KEKRecipientInfo types CMS_set1_key() should be used and B and B set to NULL. The following flags can be passed in the B parameter. If the B flag is set MIME headers for type B are deleted from the content. If the content is not of type B 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 need to hold all data in memory as mentioned in CMS_verify() also applies to CMS_decrypt(). =head1 SEE ALSO L, L =head1 HISTORY CMS_decrypt() was added to OpenSSL 0.9.8 =cut