A New Proposal Against the Main of Generic Attacks

This paper presents a effcient proposal for iterating hash functions to prevent the main of generic attacks such as Multicollisions Attack,Second Preimage Attack and Herding Attack.Based on this proposal,it’s possible that a secure hash function can be built with iterating compression functions . The proposal mainly contains a method called ” Shifting Whole Message”,it regroups the cascaded messages to be new blocks and makes the known results of the pre-computed blocks noneffective

LAB Form for Iterated Hash Functions

In this paper,we proposed a efficient and laconic mode for iterative hash functions and tried to fix the flaws of the Merkle-Damgaard construction completely and certainly tried to prevent varieties of those generic attacks ,such as Multicollisions Attack,Second Preimage Attack and Herding Attack.The struc- ture of this new mode is different from HAIFA or any other proposal,it contains a new method “Locking Abutting Blocks”(LAB)with checksum ,it makes a larger size of connotative chaining value without requirements of intricate computing and larger memory and it allows for an online computation in one pass with a fixed memory independently .It’s also easy to avoid the generic attacks (presented by Praveen Gauravaram and John Kelsey) which apply on the hash functions with linear-XOR/additive checksum

Active Domain Expansion for Normal Narrow-pipe Hash Functions

Recently several reports of Cryptology ePrint Archive showed the discovering that for a normal iterative hash function the entropy and codomain would reduce greatly,then some conclusions were given: Narrow-pipe hash functions couldn’t resist this reducing (But wide-pipe hash functions could.),and generic collision attacks on narrow-pipe hash functions would be faster than birthday paradox.The discovering and conclusions rely on the cases of active domain reducing which causes the empty set of a approximative probability e −1 in a iteration.However,we can thwart the conclusions by the way of Active Domain Expansion to keep or recover the entropy, by some amending for any a normal narrow-pipe hash function to realize it.And some hash mode such as LAB Mode[1]can more simply do it.In this paper,we’d introduce Active Domain Expansion which includes Surjection Round and the sum block ΣMi.The most important is to define a sum block ΣMi to replace the input of a normal message block Mi in compression function.ΣMi is a sum of the foregoing i “Encoded Blocks”.since the surjection round has the same purport and the form is a part of Active Domain Expansion,Surjections Round will be non-critical section in this paper.Besides,we can redefine the last block of additional bits.By these,a normal narrow-pipe hash function can resist the reducing completely.. keywords: narrow-pipe hash, Active Domain Expansion,Encoded Block,entropy, recove

A Collision-resistance Hash Function DIHA2

Abstract. The new hash function DIHA2 (Dynamic Input Hash Algorithm)is with the structure of Merkle-Damgard and is based on 64-bit computing.It oper- ates each 1024-bit block and outputts a 256-bit hash-value. For a 64-bit sub-block X[j](0 ≤ j ≤ 15) of each step, DIHA2 gets a dynamic mapping value of TLU (table look up,The table was 256-Byte only)and add it to operation of variables a, b, c, d,so as to eliminate the differential effect.At the same time DIHA2 sets 3 assistant register variables r1, r2, r3 to store the mapping value and resume loading 3 steps later, so as to be interleaving. DIHA2 therefore obtained strong avalanche effect than the others and can resist the sharp and serious attack of differential