The Mathematics of Public-Key Cryptography, Lecture 21
November 28, 2000
Summary of material covered in lecture 21
- review of the random oracle model
- discussion of hash-generic algorithms
- comparison to generic group algorithms
- Full domain hash (FDH)
- review of the reduction: construction of
an algorithm Invert to invert f, given an algorithm Forge
that constructs forged signatures with a specified probability
(assuming Forge is successful in a key-only attack)
- detailed analysis of success probability of Invert
- modification of the reduction to the situation where
Forge is successful in a chosen message attack
- discussion of how Invert can generate valid signatures
in FDH without being able to invert f
- informal discussion of the analysis
of success probability of Invert