mirrors/zig
1
0
Fork 0
mirror of https://codeberg.org/ziglang/zig.git synced 2025-12-06 13:54:21 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 1

Split AES struct into AESEncrypt and AESDecrypt

Browse source
This commit is contained in:
Žiga Željko 2020-04-28 04:52:42 +08:00
parent 45f4a1124f
commit 130435a17a
1 changed files with 66 additions and 8 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

74
lib/std/crypto/aes.zig
View file

@ -130,21 +130,55 @@ fn AES(comptime keysize: usize) type {
return struct {
const Self = @This();
pub const Encrypt = AESEncrypt(keysize);
pub const Decrypt = AESDecrypt(keysize);
const nn = (keysize / 8) + 28;
enc: [nn]u32,
dec: [nn]u32,
enc: Encrypt,
dec: Decrypt,
pub fn init(key: [keysize / 8]u8) Self {
var ctx: Self = undefined;
expandKey(&key, ctx.enc[0..], ctx.dec[0..]);
ctx.enc = Encrypt.init(key);
ctx.dec = ctx.enc.toDecrypt();
return ctx;
}
pub fn encrypt(ctx: Self, dst: []u8, src: []const u8) void {
encryptBlock(ctx.enc[0..], dst, src);
ctx.enc.encrypt(dst, src);
}
pub fn decrypt(ctx: Self, dst: []u8, src: []const u8) void {
decryptBlock(ctx.dec[0..], dst, src);
ctx.dec.decrypt(dst, src);
}
pub fn ctr(ctx: Self, dst: []u8, src: []const u8, iv: [16]u8) void {
ctx.enc.ctr(dst, src, iv);
}
};
}
fn AESEncrypt(comptime keysize: usize) type {
return struct {
const Self = @This();
const Decrypt = AESDecrypt(keysize);
const nn = (keysize / 8) + 28;
enc: [nn]u32,
pub fn init(key: [keysize / 8]u8) Self {
var ctx: Self = undefined;
expandKeyEncrypt(&key, ctx.enc[0..]);
return ctx;
}
pub fn toDecrypt(ctx: Self) Decrypt {
var dec: Decrypt = undefined;
expandKeyDecrypt(ctx.enc[0..], dec.dec[0..]);
return dec;
}
pub fn encrypt(ctx: Self, dst: []u8, src: []const u8) void {
encryptBlock(ctx.enc[0..], dst, src);
}
pub fn ctr(ctx: Self, dst: []u8, src: []const u8, iv: [16]u8) void {
std.debug.assert(dst.len >= src.len);
@ -163,6 +197,27 @@ fn AES(comptime keysize: usize) type {
};
}
fn AESDecrypt(comptime keysize: usize) type {
return struct {
const Self = @This();
const nn = (keysize / 8) + 28;
dec: [nn]u32,
pub fn init(key: [keysize / 8]u8) Self {
var ctx: Self = undefined;
var enc: [nn]u32 = undefined;
expandKeyEncrypt(key[0..], enc[0..]);
expandKeyDecrypt(enc[0..], ctx.dec[0..]);
return ctx;
}
pub fn decrypt(ctx: Self, dst: []u8, src: []const u8) void {
decryptBlock(ctx.dec[0..], dst, src);
}
};
}
test "ctr" {
// NIST SP 800-38A pp 55-58
{
@ -247,7 +302,7 @@ test "decrypt" {
}
// Key expansion algorithm. See FIPS-197, Figure 11.
fn expandKey(key: []const u8, enc: []u32, dec: []u32) void {
fn expandKeyEncrypt(key: []const u8, enc: []u32) void {
var i: usize = 0;
var nk = key.len / 4;
while (i < nk) : (i += 1) {
@ -262,9 +317,11 @@ fn expandKey(key: []const u8, enc: []u32, dec: []u32) void {
}
enc[i] = enc[i - nk] ^ t;
}
}
fn expandKeyDecrypt(enc: []const u32, dec: []u32) void {
var i: usize = 0;
var n = enc.len;
i = 0;
while (i < n) : (i += 4) {
var ei = n - i - 4;
var j: usize = 0;
@ -308,7 +365,8 @@ test "expand key" {
};
var enc: [exp_enc.len]u32 = undefined;
var dec: [exp_dec.len]u32 = undefined;
expandKey(key[0..], enc[0..], dec[0..]);
expandKeyEncrypt(key[0..], enc[0..]);
expandKeyDecrypt(enc[0..], dec[0..]);
testing.expectEqualSlices(u32, exp_enc[0..], enc[0..]);
testing.expectEqualSlices(u32, exp_dec[0..], dec[0..]);
}