Patent ID: 7392382

Claim:
A computer-implemented method of verifying data timeliness with time-based derived cryptographic keys, the method comprising: receiving a master key; receiving an identity of a current time interval; wherein the master key and the identity of the current time interval are received from a key server; deriving a first interval key based on both the master key and a first time interval; and decrypting first data that was encrypted with the first interval key wherein the first time interval is determined based on a first time and the identity of the current time interval; during a first interval of time, encrypting, with the first interval key, all data that is to be communicated to a particular group of recipients during the first interval of time; deriving a second interval key based on both the master key and a second time that differs from the first time; and during a second interval of time that occurs after the first interval of time, encrypting, with the second interval key, all data that is to be communicated to the particular group of recipients during the second interval of time.