PKCS7_decrypt(3)

     NAME
          PKCS7_decrypt - decrypt content from a PKCS#7 envelopedData
          structure

     SYNOPSIS
          int PKCS7_decrypt(PKCS7 *p7, EVP_PKEY *pkey, X509 *cert, BIO
          *data, int flags);

     DESCRIPTION
          PKCS7_decrypt() extracts and decrypts the content from a
          PKCS#7 envelopedData structure. pkey is the private key of
          the recipient, cert is the recipients certificate, data is a
          BIO to write the content to and flags is an optional set of
          flags.

     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.

          The following flags can be passed in the flags parameter.

          If the PKCS7_TEXT flag is set MIME headers for type
          text/plain are deleted from the content. If the content is
          not of type text/plain then an error is returned.

     RETURN VALUES
          PKCS7_decrypt() returns either 1 for success or 0 for
          failure.  The error can be obtained from ERR_get_error(3)

     BUGS
          PKCS7_decrypt() must be passed the correct recipient key and
          certificate. It would be better if it could look up the
          correct key and certificate from a database.

          The lack of single pass processing and need to hold all data
          in memory as mentioned in PKCS7_sign() also applies to
          PKCS7_verify().

     SEE ALSO
          ERR_get_error(3), PKCS7_encrypt(3)

     HISTORY
          PKCS7_decrypt() was added to OpenSSL 0.9.5