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Method for Improving Cryptographic Ciphers Against Power-Analysis Attacks Disclosure Number: IPCOM000013787D
Original Publication Date: 2001-Apr-14
Included in the Prior Art Database: 2003-Jun-18

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A novel approach to secure the implementations of security-sensitive applications using cryptographic means implemented on hardware tokens susceptible to external power-analysis attacks is described. In particular, two complemental techniques are presented that thwart a class of attacks known as Differential Power Analysis (DPA) against smart cards. An example is given of how these techniques can be applied in a non-invasive way to an existing e-cash protocol. Background A smart card is a hardware token the size of a credit card. It bears a microprocessor executing instructions controlled by some control software loaded in its internal memory. In order to execute security-sensitive applications like handling electronic cash or performing login operations, a smart card typically contains software or hardware implementing cryptographic algorithms. Due to the size and cost constraints of a smart card, no card-internal power source is typically present on a card. Therefore, all power for executing the instructions on the smart card has to be provided by the card-external world, so-called smart card terminals. Problem solved