Formalizing human ignorance collision-resistant hashing without the keys

• Main Author: Phillip Rogaway
• Format: Book Series
• Published: 2018
• Subjects: Computer Science; Mathematics
• Online Access: https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84887264252&origin=inward; http://cmuir.cmu.ac.th/jspui/handle/6653943832/61601
• Institution: Chiang Mai University

There is a rarely mentioned foundational problem involving collision-resistant hash-functions: common constructions are keyless, but formal definitions are keyed. The discrepancy stems from the fact that a function H: {0,1}*→ {0, 1}nalways admits an efficient collision-finding algorithm, it's just that us human beings might be unable to write the program down. We explain a simple way to sidestep this difficulty that avoids having to key our hash functions. The idea is to state theorems in a way that prescribes an explicitly-given reduction, normally a black-box one. We illustrate this approach using well-known examples involving digital signatures, pseudorandom functions, and the Merkle-Damgård construction. © Springer-Verlag Berlin Heidelberg 2006.