Universal One-Way Hash Functions via Inaccessible Entropy

This paper revisits the construction of Universal One-Way Hash Functions (UOWHFs) from any one-way function due to Rompel (STOC 1990). We give a simpler construction of UOWHFs, which also obtains better efficiency and security. The construction exploits a strong connection to the recently introduced notion of inaccessible entropy (Haitner et al. STOC 2009). With this perspective, we observe that a small tweak of any one-way function f is already a weak form of a UOWHF: Consider F(x, i) that outputs the i-bit long prefix of f(x). If F were a UOWHF then given a random x and i it would be hard to come up with x = x such that F(x, i) = F(x , i). While this may not be the case, we show (rather easily) that it is hard to sample x with almost full entropy among all the possible such values of x . The rest of our construction simply amplifies and exploits this basic property. With this and other recent works, we have that the constructions of three fundamental cryptographic primitives (Pseu...

• Type: Conference
• Year: 2010
• Where: EUROCRYPT
• Authors: Iftach Haitner, Thomas Holenstein, Omer Reingold, Salil P. Vadhan, Hoeteck Wee
• Keywords: Cryptology, EUROCRYPT 2010, Inaccessible Entropy, One-way Functions, One-way Hash Functions