Correlation Electromagnetic Analysis for Cryptographic Device

The article analyzes the CMOS logical gate´s electric current characteristic under the active status, establishes the electromagnetic information leakage hamming distance model in registers level. Aimed at the data encryption standard (DES) cryptographic system realized by the P89C668 microcomputer, Correlation Electromagnetic Analysis (CEMA) algorithm was described, the choosing of attack point D and the computational method were analyzed, an attack experiment was processed by CEMA, thereby obtaining 48-bits sub-key of the 16th round of DES. The result shows that EM information leakage exists in CMOS integrated circuit during work, XOR operation in each round of DES is an attack point. It can provide a basis for implementing protective measures in the cryptographic systems.