Design Of Random Oracle For Block Iterated One-Way Ciphers Through Polynomial Functions

Abstract

The security aspect on provably secure hash function relies upon the design principles of Random Oracle (RO). Poor design principles make the said function vulnerable to hash attacks. The conventional keyless provably secure hash functions MD-5, SHA-2 and SHA-3 use RO or Sponge principles for the design and construction of hash function. They use bitwise operators AND, OR, XOR and modulo arithmetic for processing the input blocks. These operators are simple to use and they are efficient in terms of achieving quick response time. At the same time the repeated use of them in the input blocks may invite hash collisions. The proposed design advocates the use of multi variable higher-order polynomial function for the design of round function in RO. The new design paradigm derogates the use of bitwise operators at block level processing and hardens the internal structure of RO with higher- order polynomial function to ensure better security. The results prove that, the new prototype helps the block iterated hash function to exhibit strong random behavior even for a small bit flip in the input. Therefore, performing differential analysis on the proposed design is very hard than ever before.