Added external functions

            external function fx_verifySignature(in octetstring p_message, in octetstring p_signedMessage, in octetstring p_key) return boolean;

        	/**

        	 * @desc	Calculate a pseudo-random integer value as described in RFC2246

        	 * @desc	Generate a pseudo-random integer value as described in RFC2246

        	 * @return	A random integer value

        	 */

            external function fx_random( ) return integer;

        	/**

        	 * @desc	Compute a cryptographic checksum using ISO/IEC 9797-1 MAC algorithm 3

        	 * 			with block cipher DES, zero IV (8 bytes) and ISO9797-1 padding method 2.

        	 * @param	p_ssc Send Sequence Counter

        	 * @param	p_key DES key, concatenation of 2 equal-length keys (Ka || Kb)

        	 * @param	p_data Data for which the cryptographic checksum is computed

        	 * @return	Cryptographic checksum of p_data (8 bytes).

        	 */            

            external function fx_cryptographicChecksum(in octetstring p_ssc, in octetstring p_key, in octetstring p_data) return octetstring;

        	/**

        	 * @desc	Compute a digest

        	 * @param	p_algorithm Hash algorithm to be used for computing digest

        	 * @param	p_data Data for which the digest is computed

        	 * @return	Digest value of p_data

        	 */            

            external function fx_digest(in HashAlgorithm p_algorithm, in octetstring p_data) return octetstring;

		} // end securityExternalFunctions

		group fileExternalFunctions {

    	// ISO/IEC 9797-1 MAC Algorithm 3 

	    function f_cryptographicChecksum(in octetstring p_key, in octetstring p_data) 

	    return octetstring {

	    	// TODO

	    	return ''O; 

	    	// FIXME

	    	return fx_cryptographicChecksum(''O, p_key, p_data);

    	} // end f_cryptographicChecksum

    	// TDES Encryption

    	function f_digest(in HashAlgorithm p_algorithm, in octetstring p_data) return octetstring {

    		// FIXME

    		// return fx_digest(p_algorithm, p_data);

    		return '0001020304050607'O; 

    	} //end f_digest