Discussion of One Improved Hash Algorithm Based on MD 5 and SHA 11

We have devised one 160 bits improved hash algorithm based on MD5 and SHA1. And in additional, we also introduce four assistant functions named:F(X,Y,Z), G(X,Y,Z), H(X,Y,Z), and I(X,Y,Z) to do 4 rounds of 16 steps iterative operation with 32-bit data as input and 32-bit as output, saving in A, B, C, D respectively. Then we use one new extending function K(X,Y,Z) to expand 32-bit A, B, C, D to 40-bit. At last, by combining the result from low-bit AA, we realize the 160-bit hash algorithm. By analysis, we have found that: without increasing the time complexity, the improved algorithm has increased the security better compared with MD5 and SHA1 algorithms.