code: private String generateHash(String secret) {
  
  		//check for any null values and set them to empty string for hashing
  		String timeStamp = null == this.timeStamp ? "" : this.timeStamp;
  		String merchantId = null == this.merchantId ? "" : this.merchantId;
  		String orderId = null == this.orderId ? "" : this.orderId;
  		String result = null == this.result ? "" : this.result;
  		String message = null == this.message ? "" : this.message;
  		String pasRef = null == this.pasRef ? "" : this.pasRef;
  		String authCode = null == this.authCode ? "" : this.authCode;
  
  		//create String to hash
  		String toHash = new StringBuilder().append(timeStamp)
  				.append(".")
  				.append(merchantId)
  				.append(".")
  				.append(orderId)
  				.append(".")
  				.append(result)
  				.append(".")
  				.append(message)
  				.append(".")
  				.append(pasRef)
  				.append(".")
  				.append(authCode)
  				.toString();
  
  		return GenerationUtils.generateHash(toHash, secret);
  	}
docs: Creates the security hash from a number of fields and the shared secret.
  
  @param secret
  @return String