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Move oracle to cipher

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This commit is contained in:
Armin Friedl 2025-02-15 13:18:17 +01:00
parent f9f27c772e
commit 54a4cef76e
2 changed files with 41 additions and 41 deletions
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40
src/aes.zig
View file

@ -155,6 +155,46 @@ pub const AES = struct {
}
};
pub const ECB_CBC_Oracle = struct {
mode: Mode,
alloc: std.mem.Allocator,
padded_input: []u8 = undefined,
pub fn init(alloc: std.mem.Allocator, mode: Mode) @This() {
return @This(){ .alloc = alloc, .mode = mode };
}
pub fn oracleFn(self: *@This(), alloc: std.mem.Allocator, input: []const u8) ![]u8 {
var rng = std.crypto.random;
const padding_start = rng.intRangeAtMost(u32, 0, 16);
const padding_end = 16 - padding_start;
self.padded_input = try self.alloc.alloc(u8, (padding_start + input.len + padding_end));
std.crypto.random.bytes(self.padded_input[0..padding_start]);
std.crypto.random.bytes(self.padded_input[(padding_start + input.len)..]);
const key = try self.alloc.alloc(u8, 16);
defer self.alloc.free(key);
std.crypto.random.bytes(key);
const iv = try self.alloc.alloc(u8, 16);
defer self.alloc.free(iv);
std.crypto.random.bytes(iv);
var cipher = switch (self.mode) {
.ECB => AES.init_ecb(self.alloc, key),
.CBC => AES.init_cbc(self.alloc, key, iv),
};
defer cipher.deinit();
return try cipher.encrypt(alloc, input);
}
pub fn deinit(self: *@This()) void {
self.alloc.free(self.padded_input);
}
};
test "ecb" {
const allocator = std.testing.allocator;

42
src/main.zig
View file

@ -309,46 +309,6 @@ fn s2c10(allocator: std.mem.Allocator, stdout: anytype) !void {
}
fn s2c11(allocator: std.mem.Allocator, stdout: anytype) !void {
const Oracle = struct {
mode: aes.Mode,
alloc: std.mem.Allocator,
padded_input: []u8 = undefined,
fn init(alloc: std.mem.Allocator, mode: aes.Mode) @This() {
return @This(){ .alloc = alloc, .mode = mode };
}
pub fn oracleFn(self: *@This(), alloc: std.mem.Allocator, input: []const u8) ![]u8 {
var rng = std.crypto.random;
const padding_start = rng.intRangeAtMost(u32, 0, 16);
const padding_end = 16 - padding_start;
self.padded_input = try self.alloc.alloc(u8, (padding_start + input.len + padding_end));
std.crypto.random.bytes(self.padded_input[0..padding_start]);
std.crypto.random.bytes(self.padded_input[(padding_start + input.len)..]);
const key = try self.alloc.alloc(u8, 16);
defer self.alloc.free(key);
std.crypto.random.bytes(key);
const iv = try self.alloc.alloc(u8, 16);
defer self.alloc.free(iv);
std.crypto.random.bytes(iv);
var cipher = switch (self.mode) {
.ECB => aes.AES.init_ecb(self.alloc, key),
.CBC => aes.AES.init_cbc(self.alloc, key, iv),
};
defer cipher.deinit();
return try cipher.encrypt(alloc, input);
}
fn deinit(self: *@This()) void {
self.alloc.free(self.padded_input);
}
};
for (0..1000) |_| {
const mode_rnd = std.crypto.random.intRangeAtMost(u1, 0, 1);
const mode = switch (mode_rnd) {
@ -356,7 +316,7 @@ fn s2c11(allocator: std.mem.Allocator, stdout: anytype) !void {
1 => aes.Mode.CBC,
};
var oracle = Oracle.init(allocator, mode);
var oracle = aes.ECB_CBC_Oracle.init(allocator, mode);
defer oracle.deinit();
const result = try aes_crack.detect_ecb_cbc(allocator, &oracle);