Patent ID: 7200656

Claim:
A method of analyzing communication in a network, comprising: obtaining time of arrival information for chunks of data in the network; constructing a signal to represent the time of arrival information; processing the signal to obtain periodicity information about both short-term periodicity and long-term periodicity of the signal, wherein the processing includes: generating a spectrogram that plots arrival frequency of the chunks of data against time from the signal, and constructing a cepstrogram that contrasts short-term arrival periods of data chunks against long-term periods from the spectrogram, wherein the constructing a cepstrogram includes performing cepstrum processing on both rows and columns of the spectrogram; generating a signature associated with the chunks of data from the short-term and long-term periodicity of the signal; and classifying a type of the communication associated with the chunks of data using the signature, wherein the short-term and long-term periodicity of the signal is used to generate the signature associated with the chunks of data, even when the data is encrypted.