From 36d47dd1991f0ccd7a9673075624f09500cc415e Mon Sep 17 00:00:00 2001
From: Frank Denis <124872+jedisct1@users.noreply.github.com>
Date: Tue, 7 Mar 2023 10:04:45 +0100
Subject: [PATCH] std.crypto.hash.sha3: add TurboSHAKE (#14824)

---
 lib/std/crypto/benchmark.zig |  2 ++
 lib/std/crypto/keccak_p.zig  |  4 ++--
 lib/std/crypto/sha3.zig      | 33 +++++++++++++++++++++++++++++++--
 3 files changed, 35 insertions(+), 4 deletions(-)

diff --git a/lib/std/crypto/benchmark.zig b/lib/std/crypto/benchmark.zig
index e6e0e1fc3930..47ca24aa6651 100644
--- a/lib/std/crypto/benchmark.zig
+++ b/lib/std/crypto/benchmark.zig
@@ -27,6 +27,8 @@ const hashes = [_]Crypto{
     Crypto{ .ty = crypto.hash.sha3.Sha3_512, .name = "sha3-512" },
     Crypto{ .ty = crypto.hash.sha3.Shake128, .name = "shake-128" },
     Crypto{ .ty = crypto.hash.sha3.Shake256, .name = "shake-256" },
+    Crypto{ .ty = crypto.hash.sha3.TurboShake128(null), .name = "turboshake-128" },
+    Crypto{ .ty = crypto.hash.sha3.TurboShake256(null), .name = "turboshake-256" },
     Crypto{ .ty = crypto.hash.Gimli, .name = "gimli-hash" },
     Crypto{ .ty = crypto.hash.blake2.Blake2s256, .name = "blake2s" },
     Crypto{ .ty = crypto.hash.blake2.Blake2b512, .name = "blake2b" },
diff --git a/lib/std/crypto/keccak_p.zig b/lib/std/crypto/keccak_p.zig
index 10367caffd34..cef3b0cce4c8 100644
--- a/lib/std/crypto/keccak_p.zig
+++ b/lib/std/crypto/keccak_p.zig
@@ -175,12 +175,12 @@ pub fn KeccakF(comptime f: u11) type {
         /// Apply a (possibly) reduced-round permutation to the state.
         pub fn permuteR(self: *Self, comptime rounds: u5) void {
             var i = RC.len - rounds;
-            while (i < rounds - rounds % 3) : (i += 3) {
+            while (i < RC.len - RC.len % 3) : (i += 3) {
                 self.round(RC[i]);
                 self.round(RC[i + 1]);
                 self.round(RC[i + 2]);
             }
-            while (i < rounds) : (i += 1) {
+            while (i < RC.len) : (i += 1) {
                 self.round(RC[i]);
             }
         }
diff --git a/lib/std/crypto/sha3.zig b/lib/std/crypto/sha3.zig
index 985027f3eee3..6fc4977f0b21 100644
--- a/lib/std/crypto/sha3.zig
+++ b/lib/std/crypto/sha3.zig
@@ -18,6 +18,20 @@ pub const Keccak_512 = @compileError("Deprecated: use `Keccak512` instead");
 pub const Shake128 = Shake(128);
 pub const Shake256 = Shake(256);
 
+/// TurboSHAKE128 is a XOF (a secure hash function with a variable output length), with a 128 bit security level.
+/// It is based on the same permutation as SHA3 and SHAKE128, but which much higher performance.
+/// The delimiter is 0x01 by default, but can be changed for context-separation.
+pub fn TurboShake128(comptime delim: ?u8) type {
+    return TurboShake(128, delim);
+}
+
+/// TurboSHAKE256 is a XOF (a secure hash function with a variable output length), with a 256 bit security level.
+/// It is based on the same permutation as SHA3 and SHAKE256, but which much higher performance.
+/// The delimiter is 0x01 by default, but can be changed for context-separation.
+pub fn TurboShake256(comptime delim: ?u8) type {
+    return TurboShake(256, delim);
+}
+
 /// A generic Keccak hash function.
 pub fn Keccak(comptime f: u11, comptime output_bits: u11, comptime delim: u8, comptime rounds: u5) type {
     comptime assert(output_bits > 0 and output_bits * 2 < f and output_bits % 8 == 0); // invalid output length
@@ -76,9 +90,18 @@ pub fn Keccak(comptime f: u11, comptime output_bits: u11, comptime delim: u8, co
 
 /// The SHAKE extendable output hash function.
 pub fn Shake(comptime security_level: u11) type {
+    return ShakeLike(security_level, 0x1f, 24);
+}
+
+/// The TurboSHAKE extendable output hash function.
+/// https://datatracker.ietf.org/doc/draft-irtf-cfrg-kangarootwelve/
+pub fn TurboShake(comptime security_level: u11, comptime delim: ?u8) type {
+    return ShakeLike(security_level, delim orelse 0x01, 12);
+}
+
+fn ShakeLike(comptime security_level: u11, comptime delim: u8, comptime rounds: u5) type {
     const f = 1600;
-    const rounds = 24;
-    const State = KeccakState(f, security_level * 2, 0x1f, rounds);
+    const State = KeccakState(f, security_level * 2, delim, rounds);
 
     return struct {
         const Self = @This();
@@ -348,3 +371,9 @@ test "SHAKE-256 single" {
     Shake256.hash("hello123", &out, .{});
     try htest.assertEqual("ade612ba265f92de4a37", &out);
 }
+
+test "TurboSHAKE-128" {
+    var out: [32]u8 = undefined;
+    TurboShake(128, 0x06).hash("\xff", &out, .{});
+    try htest.assertEqual("8ec9c66465ed0d4a6c35d13506718d687a25cb05c74cca1e42501abd83874a67", &out);
+}