Symmetric Key Cryptographic Technique Using Digital Logic Concept

The session based symmetric key Cryptographic Technique using Digital Logic concept has been proposed in this paper and the technique is termed as CTDL. The proposed technique consider the plain text as a stream of finite number of binary bits and divided it into blocks with different lengths. In each block, bit positions are changed using the concept of logical Ex-OR or Ex-NOR operation to generate the encrypted block. Cipher text is generated from these encrypted blocks. A session based key is generated using the values of block length and the type of digital logic operation used for particular blocks. Results are computed using twenty files with different sizes and types to compare CTDL with standard symmetric key cryptographic techniques Triple-DES (168bits) and AES (128bits) with respect to the Encryption and Decryption times, Avalanche and Strict Avalanche values, Chi-square values and some other statistical measures like median, mode, standard deviation and correlation coefficient. Index Termsâ€”AES, CTDL, Session based symmetric key cryptography, Triple-DES.