Tagged Questions
0
votes
0answers
37 views
ElGamal signature: Forging a signature of a specific form
I have a question I can't solve from one of the courses I'm currently taking:
Show that given a legitimate ElGamal signature $(S,R)$ on a given message $m$, an attacker
can compute a signature ...
0
votes
1answer
122 views
Can we trust digital signatures?
Consider that Alice wants to send a digitally signed message to Bob.
Mallory might be able to publish his public key under Alice's name and then impersonate Alice to send a message with an apparently ...
2
votes
2answers
255 views
Lamport signature: How many signatures are need to forge a signature?
Lamport signature: Signing the message Note that now Alice's private key is used and should never be used again. The other 256 random numbers that she did not use for the signature she must never ...
2
votes
0answers
584 views
An existential forgery attack on ElGamal [closed]
From an old exam question:
Consider this existential forgery attack on ElGamal. Choose $u$, and $v$ such that $\operatorname{gcd}(v, p - 1) = 1$.
Compute $r := y^v g^u \mod p$ and $s := ...
