Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : LFSR


Proposed Method to Encrypt Images to Mobile Device Based on the Principles of Shannon

Hanna M .A .Salman; Anwar Abbas Hattab

Engineering and Technology Journal, 2016, Volume 34, Issue 6, Pages 820-830

In the proposed research, it has been proposed image encryption method in the mobile device based on the principles of Shannon (diffusion and confusion). Where: a large group of keys is used. The process of entering the keys by the user is a very difficult In the proposed method; all the keys are extracted from the mathematical image properties, by a process of summation operation and the value of the mean. Image processing passes in to two phases, the first phase by using the output of the process of summation as a key to achieve the diffusion. In the second phase, the value of the mean is used as a seed to LFSR (Linear feedback register) to generate akey equal to the block of the image. Then process of the x or-operation (XOR) between the key and the block of image should be treated the output of these two phases is an image with the same of the original image size. Then by applying calculated time of encryption and decrypted are found the proposed method is simple, fast, and sensitive to the key. The suggested method meets the performance analysis examinations such as histogram, correlation, power spectrum, NPCR, UACI, Entropy and acceptable encryption speed; and it is resistant to statistical, brute force, and differential attacks.

Improvement Majority Function in A5/1 stream cipher Algorithm

Hala Bahjat; Mohanad Ali

Engineering and Technology Journal, 2016, Volume 34, Issue 1, Pages 16-25

Security is an important issue, especially in today’s technologically advanced society. Global System for Mobile Communications (GSM) is a world-wide standard for digital wireless communication. GSM uses A5/1 stream cipher in order to provide privacy on air communication. This paper introduce new improvements to the A5/1 stream cipher in order overcome the weakness that appear in clocking mechanism that used in A5/1 stream cipher. New S-box generation is proposed to increase the efficient for A5/1 majority function and improve randomness features. The randomness results confirm that the output bit-stream generated by the proposed stream cipher has improved the randomness performance.

Improving Keystream Generation for Sosemanuk Stream Cipher Using Twofish Block Cipher

Rana S. Mohammed; Shant K. Avakian

Engineering and Technology Journal, 2009, Volume 27, Issue 10, Pages 1976-1991

This paper will introduce two proposal algorithms (Snowfish 1) and the
(Snowfish 2) to improve the Sosemanuk stream cipher algorithm by benefiting from
the efficient properties of the Twofish block cipher and also use its key schedule, keydependent
Sbox to increase the security, randomness and try to avoid the guess and
determine attack of Sosemanuk. These two proposals use Twofish algorithm rather
than Serpent algorithm which was used in the Sosemanuk and also they use keydependent
Sbox rather than static Sbox. They are similar in the same key length (128
to 256 bit), IV length (128 bit), LFSR length, FSM functions and output
transformation.
In this paper will make a comparison between Snowfish 1, Snowfish 2 and
Sosemanuk algorithms by using the tests of randomness, the structural tests and the
complexity of the algorithm. These tests give results that show the two proposed
algorithms have good results in increasing the security and randomness compared
with Sosemanuk algorithm.