Analysis Of The Data Encryption Algorithm Improvements And Applications

The cipher is very important in our information society, governmental documents, martial secret, commercial secret and private secret are all need to be encrypted. More and more people have taken high attention to cryptology.The usually cipher now are symmetric-key encrytion schemes and the asymmetric-key encrytion schemes. There are two parts of symmetric-key encrytion schemes-block cipher and stream cipher. This article analyzed several arithmetics of them and designed 3M-DES which stronger than DES but made from DES.Till C.E.Shannon's Communication Theory of Secrecy Systems in 1949, crphtology has become a formal science. And the appearance of DES in 1977 made highly attention of the world. The research of cipher has greatly improved.However, continued advances in computation speed have now placed DES in range of attack. For the future we need a stronger cipher. But in the fact the arithmetic of DES itself is great, it is weakly in it's 64bits block and 64bits key, it's evident shortly. Based of this, I increased the length of DES's block and key and designed a new cipher 3M-DES.3M-DES maintained the core F function of DES, join 3 of DES blocks(as same as to more blocks), made a new cipher with 192bits block and 192bits key. By 16 turns of DES, the data and the key can be overall diffused.I also used vc 6.0 designed a Data-Encrytion software including DES, 3DES, Gost, AES, IDEA, RC-5, Safer K-64 and 3M-DES to analyze these arithmetics. The fact is, the increased length of block and key made 3M-DES's diffusion much better than DES, and almost the same speed as DES, to encrypt the same size file, 3M-DES has only 1/40-1/80 slow than DES.The disadvantage of 3M-DES is the generate of key is unattached, not overall diffused before encrypt the data, this may be discount the length of 192bits.