Thumbnail-preserving encryption by sum-preserving within blocks based on exponential chaotic mapping

Abstract

In recent years, chaotic sequences have been widely used in image encryption. Wuqi proposed a new rule which one-dimensional discrete chaotic mapping should follow, based on which a noval one-dimensional chaotic mapping was created from the definition of Lyapunov exponent (LE), and this chaotic mapping was combined with a three-pixel thumbnail-preserved encryption (TPE). Diffrent from the existing TPE schemes, the scheme uses a three-pixel sum preserving encryption (SPE) scheme as an example and uses mathematical expressions to illustrate the encryption and decryption methods. The experimental results show that the proposed chaotic mapping has good chaotic properties. Based on this novel TPE scheme, the encrypted image has both high security and usability, which is also competitive with other schemes.

A two-dimensional chaotic model and its application in image encryption

“…Since the overall confusion operation we use is based on the indexing of the chaotic model. In order to overcome the possible short period phenomenon of the chaotic model, we first perform the block confusion, and the construction of the block confusion table is derived from [19]. In addition to this we performed a simple bit plane shift operation, which is briefly simulated in figure 11, the matrix M¢ is obtained.…”

“…According to the first four keys generated as the initial value, iterate the equation (9) L × W × 3 times, take a 1 = 1.9, a 3 = 0.1, precision is 16, to get two sequences X, Y, where X is used to generate the diffusion matrix D, Y is sorted to get the index Y index , and the last four keys are also used as the initial value, iterate the equation (9) L × W times to get two sequences X1, Y1, X1 has two purposes , one is used to determine the kind of DNA operation and the other is used to determine the DNA encoding rules, and Y1 is used to generate the decoding rules. The elements of matrix D are obtained from equation (17), DNA operation kinds are obtained from equation (18), DNA encoding rules are obtained from equation (19), and DNA decoding rules are obtained from equation (20). Table 2.…”