Patent ID: 7634083

Claim:
A cryptographic processing device for securely performing a cryptographic processing operation in a manner resistant to discovery of a secret by external monitoring of said device's power consumption, comprising: (a) an interface for receiving data to be cryptographically processed; (b) an interface for receiving an external clock signal regulating input/output operations; (c) an oscillator for generating an internal clock signal that cannot be reliably predicted from said external clock signal: (i) by incorporating unpredictable information, where said unpredictable information in said internal clock signal decreases the temporal alignment of externally measurable features of said cryptographic processing; (ii) where said decrease in temporal alignment inhibits reliable identification of specific cryptographic processing features from measurements of characteristics of said cryptographic device; (d) a processor configured to be clocked by said internal clock while said processor is cryptographically processing said data; (e) an interface for outputting said cryptographically processed data at a rate corresponding to said external clock.