9 research outputs found
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,itās possible that a
secure hash function can be built with iterating compression functions .
The proposal mainly contains a method called ā Shifting Whole Messageā,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 āLocking Abutting Blocksā(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 .Itās 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 couldnāt 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 ā1 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,weād introduce Active Domain Expansion which includes Surjection Round and the sum block Ī£Mi.The most important is to define a sum block Ī£Mi to replace the input of a normal message block Mi in compression function.Ī£Mi is a sum of the foregoing i āEncoded Blocksā.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