Secrecy and Performance Analysis of Symmetric Key Encryption Algorithms

There can be two vital criteria of selecting an algorithm to fulfil one’s encryption requirement. The security level of the cipher (secrecy) and the encryption time (performance). There is less focus on secrecy of ciphers as a security measurement, thus in this research, Shannon’s theories on secrecy of ciphers are used in-order to calculate the average secrecy of each cipher. Depending on the secrecy level and performance of the algorithm, suitable algorithm for encryption can be selected. This paper presents an analysis of some of the widely used symmetric key algorithms which fall under the categories of block and stream ciphers together with the two combined algorithms. [DES, TripleDES, AES, RC2, RC4, Hybrid1 (TripleDES+RC4) and Hybrid2 (AES+RC4) are used]. Analysis is done based on two measurement criteria under two circumstances which is described later in this paper. All the algorithms are implemented in Java using classes available in JAVA package javax.crypto. Separate classes are written to calculate the secrecy of ciphers and the encryption time. Performances of all stream ciphers are higher than that of block ciphers and the combined algorithms have similar performance level to block ciphers. Secrecy level of block ciphers are comparatively higher than that of stream ciphers but there are drastic changes as the data size increases. Hybrid ones have more stable secrecy level.