Abstract

In this paper, a new method for digital data cryptography is proposed to increase the speed of data cryptography, simplify the processes of data encryption - decryption, and to strengthen the degree of data protection. The proposed data shuffling and data blocks shuffling (DS_DBS) method is able to process messages, gray images, color images and digital speech file using the same encryption and decryption functions; changing the digital data type will not require any changes in the aforesaid functions. The proposed DS_DBS method allows data blocking (block size will be variable), and it is determined by the private key. Data encryption is applied by simple data shuffling and data blocks shuffling, while data decryption is applied by shuffling back the data blocks and shuffling back the data. These shuffling operations replace the complex logical and arithmetic operations used in other existing methods of data cryptography. The shuffling and shuffling back operations are implemented based on two secret indices keys, obtained by running two chaotic logistic map models. The proposed method utilizes a long private key with a variable length that depends on the selected number of crypto phases. It can be implemented in one or more phases; each phase is a function call to execute the encryption-decryption functions with the associated inputs. Using more than a phase, increases the security level by using longer private key, and each phase will be independent. The encrypted-decrypted result of each phase can be taken as a final result. Implementing the proposed DS_DBS method - using various data types – and examining its speed reveal not only the enhanced speed of data cryptography, but also the better quality and sensitivity of the proposed method compared to those of existing state of the art cryptography methods.

Key words: Keywords— Cryptography; Data shuffling; Data blocks shuffling; Data encryption – decryption.