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Advanced image encryption schemes for secure transmission and storage are increasingly needed for a number of applications like medical, military, satellite etc. In this paper, a novel image encryption algorithm based on Logistic and Tinkerbell map is proposed.The proposed method uses two 1-D Logistic maps with different keys and one 2-D Tinkerbell map. The chaotic sequence generated is mixed sequence from the and sequences of Tinkerbell map depending on the chaotic sequences of two logistic maps. The main advantage of such a scheme is complex chaotic behavior of the generated chaotic sequences. The security and performance of the proposed method is analyzed thoroughly by using key-sensitivity, keyspace, statistical, entropy, differential and performance analysis. The proposed approach achieves the required level of security with only one round of encryption operation. Hence the proposed method is computationally efficient.

In this paper an efficient image encryption scheme based on cyclic rotations and multiple blockwise diffusions with two chaotic maps is proposed. A Sin map is used to generate round keys for the encryption/decryption process. A Pomeau-Manneville map is used to generate chaotic values for permutation, pixel value rotation and diffusion operations. The encryption scheme is composed of three stages: permutation, pixel value rotation and diffusion. The permutation stage performs four operations on the image: row shuffling, column shuffling, cyclic rotation of all the rows and cyclic rotation of all the columns. This stage reduces the correlation significantly among neighboring pixels. The second stage performs circular rotation of pixel values twice by scanning the image horizontally and vertically. The amount of rotation is based on M × N chaotic values. The last stage performs the diffusion four times by scanning the image in four different ways: block of 8 × 8 pixels, block of 16 × 16 pixels, principal diagonally, and secondary diagonally. Each of the above four diffusions performs the diffusion in two directions (forwards and backwards) with two previously diffused pixels and two chaotic values. This stage makes the scheme resistant to differential attacks. The security and performance of the proposed method is analyzed systematically by using the key space, entropy, statistical, differential and performance analysis. The experimental results confirm that the proposed method is computationally efficient with high security.