Cryptanalysis and improvement on a cryptosystem based on a chaotic map

Cryptanalytic Performance Appraisal of Improved CCH2 Proxy Multisignature Scheme

“…Wang and Yu [20] have discussed two fatal flaws of the cryptosystem which are based on the logistic map and proposed by Wang and Xiang are pointed out. According to this, cryptanalysts could recover the plaintext by the chosen plaintext attacked in a short time.…”

“…See Figures 15,16,17,18,19,20,21,22,and 23. In improved CCH2 proxy multisignature scheme, elliptic curve based Schnorr signature scheme is used to generate and verify the signature. (mod ).…”

An enhanced sub-image encryption method

“…Therefore, it is easy to be cracked by chosen plaintext attack [13,14]. According to the encryption schemes [15][16][17][18][19][20] and there corresponding analyses [21][22][23], these schemes have the same fatal drawback: in the diffusion phase, the pixel values are changed in the static order from top to bottom and from left to right which reveals important information of the encryption method to the attackers. Most of the cryptanalyses of image encryption algorithms indicate that attackers always successfully cracked cryptosystems by using the order from top to bottom and from left to right.…”

Double image multi-encryption algorithm based on fractional chaotic time series

“…To meet this challenge, a variety of encryption schemes have been illustrated [2,3,7,11,14]. Recently, along with the rapid development of theory and application of chaos, many researchers are now focusing on the chaotic cryptography, since it has shown some exceptionally good properties in many concerned aspects regarding security, complexity, speed, computing power and computational overhead, etc [9,10,12].…”