crypto.py 文件源码

def __assemble_hmac_block(self, content, key):
        """ Produce HMAC block ASN.1 structure (MPHMACContainer)

        @developer: vsmysle

        :param content: string DER-encoded content generate HMAC of and
                        encapsulate into HMAC FLOD block
        :param key:     bytes key to use for HMAC generation

        :return: DER-encoded ASN.1 structure that encapsulates HMAC
                 block

        """
        # TODO: add exceptions

        self.logger.debug("producing HMAC block with ASN.1 structure")

        # calculating hmac digest of content
        digest = self.__generate_hmac(content, key)

        # oid for SHA1 hash function
        oid = const.SHA1_OID

        # creating instance of AlgorithmIdentifier class
        ai = asn1_dec.AlgorithmIdentifier()

        # setting corresponding parameters
        ai['algorithm'] = oid
        ai['parameters'] = univ.Null()

        # creating instance of MPHMACContainer class
        hmac_block = asn1_dec.MPHMACContainer()

        # setting corresponding parameters
        hmac_block['digestAlgorithm'] = ai
        hmac_block['digest'] = digest

        return hmac_block