Implementation And Analysis Of Pomaranch Stream Cipher

For a long time,Stream Cipher is an important area in cryptography. Under the leading of ECRYPT Stream Cipher Project, the design of stream cipher has received a lot of attention in the cryptographic recently.Pomaranch is a synchronous bit-oriented Stream Cipher algorithm, which is proposed by ECRYPT Stream Cipher Project and easily implemented in hardware platforms.Pomaranch has been improved to the eventual development of a third version. It is the first time for Pomaranch to introduce clocked jump register into the design of stream cipher,which enriching the design theory of stream cipher.Moreover, the stream cipher system that based on clocked jump register becomes an important research question. In the thesis, the algorithm of Pomaranch Version 3 algorithm is described and analyzed from Design principles, Software implementation and Security Analysis.Firstly, This thesis investigates primitive polynomial of jump register of pomaranch and displays the necessary conditions on the configuration of primitive polynomial of jump register. By setting different parameters (feedback taps). we find by the Maple software many other primitive polynomials, which have the larger jump index. Secondly, we improve on the original C code of Pomaranch to accelerate the velocity of software implementation.1.Improvement of software implementation of Jump Register. Four tables are pre-calculated and set up, and then by looking-up four tables randomly we can determine quickly whether register jump is needed or not. It is the same thing that the next state of register can be achieved by looking-up tables. 2.Precalculation the key maps.The total operation of key maps is replaced by an 8×512 two-dimensional table.Finally, the thesis discusses the problem of Linear Equivalence Bias in the clocked jump register stream cipher, and considers the evolvement of three versions of Pomaranch and reveals the design principles of the stream cipher much further.