  In this paper, we propose a novel conservative chaotic standard map-driven
dynamic DNA coding (encoding, addition, subtraction and decoding) for the image
encryption. The proposed image encryption algorithm is a dynamic DNA coding
algorithm i.e., for the encryption of each pixel different rules for encoding,
addition/subtraction, decoding etc. are randomly selected based on the
pseudorandom sequences generated with the help of the conservative chaotic
standard map. We propose a novel way to generate pseudo-random sequences
through the conservative chaotic standard map and also test them rigorously
through the most stringent test suite of pseudo-randomness, the NIST test
suite, before using them in the proposed image encryption algorithm. Our image
encryption algorithm incorporates a unique feed-forward and feedback mechanisms
to generate and modify the dynamic one-time pixels that are further used for
the encryption of each pixel of the plain image, therefore, bringing in the
desired sensitivity on plaintext as well as ciphertext. All the controlling
pseudorandom sequences used in the algorithm are generated for a different
value of the parameter (part of the secret key) with inter-dependency through
the iterates of the chaotic map (in the generation process) and therefore
possess extreme key sensitivity too. The performance and security analysis has
been executed extensively through histogram analysis, correlation analysis,
information entropy analysis, DNA sequence-based analysis, perceptual quality
analysis, key sensitivity analysis, plaintext sensitivity analysis, etc., The
results are promising and prove the robustness of the algorithm against various
common cryptanalytic attacks.
