https://github.com/EasyCrypt/easycrypt
Tip revision: 3cef12a5d08bbaf7b486bd02ca6c194f4f167bea authored by Manuel Barbosa on 10 October 2023, 09:38:20 UTC
Making this branch work with same Why3 version as main
Making this branch work with same Why3 version as main
Tip revision: 3cef12a
MAC.ec
require import FSet.
type key.
type message.
type tag.
module type Scheme = {
proc init(): unit {}
proc keygen(): key
proc mac(k:key,m:message): tag
proc verify(k:key,m:message,t:tag): bool
}.
module type Oracles = {
proc mac(m:message): tag
proc verify(m:message,t:tag): bool
}.
module Wrap(S:Scheme) = {
var qs:message fset
var k:key
proc init(): unit = {
qs <- fset0;
S.init();
k <@ S.keygen();
}
proc mac(m:message): tag = {
var r:tag;
qs <- qs `|` fset1 m;
r <@ S.mac(k,m);
return r;
}
proc verify(m:message,t:tag): bool = {
var r:bool;
r <@ S.verify(k,m,t);
return r;
}
proc fresh(m:message): bool = {
return (!mem qs m);
}
}.
module type Adv_CMA(O:Oracles) = {
proc forge(): (message * tag)
}.
module CMA(S:Scheme,A:Adv_CMA) = {
module O = Wrap(S)
module A = A(O)
proc main(): bool = {
var m:message;
var t:tag;
var forged,fresh:bool;
O.init();
(m,t) <@ A.forge();
forged <@ O.verify(m,t);
fresh <@ O.fresh(m);
return forged /\ fresh;
}
}.