Abstract Cryptography plays main role in information security, which is used to protect transformation of electronic data. Advanced Encryption Standard (AES) is symmetric block cipher that includes generation of ciphers for encryption... more
Abstract
Cryptography plays main role in information security, which is used to protect transformation of electronic data. Advanced Encryption Standard (AES) is symmetric block cipher that includes generation of ciphers for encryption and inverse ciphers for decryption. In this work, the key generation for AES algorithm based on different methods of algorithms (Linear Feed Back Shift Resister LFSR,
Message Digests MD5, and Modified Message Digests MMD5) is
presented. These methods make AES algorithm more reliable and more robust. Two different methods of generating key for AES algorithm are proposed: one was generating key by using MD5 algorithm and the other proposed new algorithm that called MMD5 to increase the randomization of MD5 algorithm, then used it to generate key for AES algorithm. Adding these algorithms cause a change in the static attribute of AES algorithm which has 128 bits length of input key to make it range from ( 1.8 1 *10+19)
bits.The two proposed algorithms for key generation of AES algorithm have been designed and simulated using MATLAB and Xilinx-ISE 14.6 Web PACK, and then implemented in XC3S700A-4FG484 FPGA. The two algorithms are programmed using VHDL code.The simulation and hardware results showed that the software processing time is greater than hardware processing time by (571*104) % for traditional AES algorithm; and by (670*104) % for MD5 or MMD5 with AES algorithm. The computation of avalanche affect for ciphering after implementation on Xilinx broad showed that MMD5 with AES algorithm have avalanche affect more than MD5 with AES algorithm and traditional AES algorithm. Furthermore, MD5 with AES algorithm have avalanche affect greater than traditional AES algorithm.
