March 31, 2016

Difference among (second) preimage resistance, collision resistance

□ Background knowledge : y=h(x) → Hash-value(y) is created when you insert input-value(x) to the Hash function

□ Preimage resistance : It is property to resist Preimage guess

○ First, hash value(y) is identified
○ It is computationally infeasible to find an input-value(x)

□ Second preimage resistance : It is property to resist Preimage guess
○ First, Input value(x) is identified
○ Finding a different input-value(x') for same hash-value(y) is computationally infeasible

□ Collision resistance : It is property to resist different input-values guess. the input-values makes same hash-value(=Collision)
○ First, No information is identified
○ Finding different input-values(x, x') of same hash-value(y) is computationally impossible