const std = @import("../index.zig"); const crypto = std.crypto; const debug = std.debug; const mem = std.mem; pub const HmacMd5 = Hmac(crypto.Md5); pub const HmacSha1 = Hmac(crypto.Sha1); pub const HmacSha256 = Hmac(crypto.Sha256); pub const HmacBlake2s256 = Hmac(crypto.Blake2s256); pub fn Hmac(comptime Hash: type) type { return struct { const Self = @This(); pub const mac_length = Hash.digest_length; pub const minimum_key_length = 0; o_key_pad: [Hash.block_length]u8, i_key_pad: [Hash.block_length]u8, scratch: [Hash.block_length]u8, hash: Hash, // HMAC(k, m) = H(o_key_pad | H(i_key_pad | msg)) where | is concatenation pub fn create(out: []u8, msg: []const u8, key: []const u8) void { var ctx = Self.init(key); ctx.update(msg); ctx.final(out[0..]); } pub fn init(key: []const u8) Self { var ctx: Self = undefined; // Normalize key length to block size of hash if (key.len > Hash.block_length) { Hash.hash(key, ctx.scratch[0..mac_length]); mem.set(u8, ctx.scratch[mac_length..Hash.block_length], 0); } else if (key.len < Hash.block_length) { mem.copy(u8, ctx.scratch[0..key.len], key); mem.set(u8, ctx.scratch[key.len..Hash.block_length], 0); } else { mem.copy(u8, ctx.scratch[0..], key); } for (ctx.o_key_pad) |*b, i| { b.* = ctx.scratch[i] ^ 0x5c; } for (ctx.i_key_pad) |*b, i| { b.* = ctx.scratch[i] ^ 0x36; } ctx.hash = Hash.init(); ctx.hash.update(ctx.i_key_pad[0..]); return ctx; } pub fn update(ctx: *Self, msg: []const u8) void { ctx.hash.update(msg); } pub fn final(ctx: *Self, out: []u8) void { debug.assert(Hash.block_length >= out.len and out.len >= mac_length); ctx.hash.final(ctx.scratch[0..mac_length]); ctx.hash.reset(); ctx.hash.update(ctx.o_key_pad[0..]); ctx.hash.update(ctx.scratch[0..mac_length]); ctx.hash.final(out[0..mac_length]); } }; } const htest = @import("test.zig"); test "hmac md5" { var out: [HmacMd5.mac_length]u8 = undefined; HmacMd5.create(out[0..], "", ""); htest.assertEqual("74e6f7298a9c2d168935f58c001bad88", out[0..]); HmacMd5.create(out[0..], "The quick brown fox jumps over the lazy dog", "key"); htest.assertEqual("80070713463e7749b90c2dc24911e275", out[0..]); } test "hmac sha1" { var out: [HmacSha1.mac_length]u8 = undefined; HmacSha1.create(out[0..], "", ""); htest.assertEqual("fbdb1d1b18aa6c08324b7d64b71fb76370690e1d", out[0..]); HmacSha1.create(out[0..], "The quick brown fox jumps over the lazy dog", "key"); htest.assertEqual("de7c9b85b8b78aa6bc8a7a36f70a90701c9db4d9", out[0..]); } test "hmac sha256" { var out: [HmacSha256.mac_length]u8 = undefined; HmacSha256.create(out[0..], "", ""); htest.assertEqual("b613679a0814d9ec772f95d778c35fc5ff1697c493715653c6c712144292c5ad", out[0..]); HmacSha256.create(out[0..], "The quick brown fox jumps over the lazy dog", "key"); htest.assertEqual("f7bc83f430538424b13298e6aa6fb143ef4d59a14946175997479dbc2d1a3cd8", out[0..]); }