signature schemes Flashcards
1
Q
signature scheme
A
5-tuple
P: finite possible messages
A: finite possible signatures
K: keyspace
for each key, signing algorithm
verification algorithm (ver giving true or false)
2
Q
forgery
A
y in a pair (x,y) giving ver true when Alice has not signed x
3
Q
key-only existential forgery
A
random y and compute e_k(y)
4
Q
known-message existential forgery
A
known y1 and y2 for x1 and x2, can produce valid signature for x1x2
5
Q
chosen message selective forgery
A
find x1,x2 such that x=x1x2 mod n
get signatures y1 and y2
signs y1y2 on x
