Patent ID: 8386774

Claim:
A logging system based on a one-way hash function, comprising: a user system, for recording a log file, initializing a message authentication code (MAC) key and an image code, adding a logging unit in the log file according to an event verification request, using the one-way hash function to generate a check value and generating an event verification response according to the check value and an image code sequence; a verifier, for transmitting the event verification request to the user system and after receiving the event verification response, using the one-way hash function to check the correctness of the received image code sequence from the user system; and a trusted third party, for receiving the initialized MAC key from the user system, receiving the check value and the image code sequence from the verifier, calculating a latest MAC key according to the initialized MAC key and the image code sequence, using the one-way hash function to check the correctness of the check value and the image code sequence and returning a log of a verification succeeded message to the user system if the image code sequence obtained by the hash calculation equals to the check value; wherein the trusted third party is controlled by a first company, the verifier is controlled by a second company, the first company is different from the second company, and datum transmitted among the verifier, the user system and the trusted third party are unencrypted.