Every time when I read a paper that has digital signature, when it comes to prove the security of a digital signature scheme, many chances that the author will use the forking lemma. The forking ...
Is Guillou-Quisquater existentially unforgeable against adaptive message attack under a random oracle model?
First of all, the Guillou-Quisquater digital signature scheme is: Note everything is $\bmod n$. Message is denoted by $m$. Private key: $s$ Public key: Hash function $H$, $e$, ...
There is a profusion of articles proposing signature schemes without random oracles (see for yourself). What does that mean, and why does it matter?