From 6a18123fec67ad54e26ea77ef8e63e67a4b17cb9 Mon Sep 17 00:00:00 2001
From: Kevin Jahns <kevin.jahns@protonmail.com>
Date: Wed, 12 Jul 2023 01:16:26 +0200
Subject: [PATCH] [sha256] add node native fallback

---
 hash/{sha256.js => sha256.fallback.js} | 79 +++++++++++---------------
 hash/sha256.node.js                    | 10 ++++
 hash/sha256.test.js                    | 14 ++++-
 package.json                           | 12 ++++
 4 files changed, 67 insertions(+), 48 deletions(-)
 rename hash/{sha256.js => sha256.fallback.js} (93%)
 create mode 100644 hash/sha256.node.js

diff --git a/hash/sha256.js b/hash/sha256.fallback.js
similarity index 93%
rename from hash/sha256.js
rename to hash/sha256.fallback.js
index 5984f1b..7ba8ade 100644
--- a/hash/sha256.js
+++ b/hash/sha256.fallback.js
@@ -8,6 +8,36 @@
 import * as binary from '../binary.js'
 import * as math from '../math.js'
 
+/**
+ * @param {number} w - a 32bit uint
+ * @param {number} shift
+ */
+const rotr = (w, shift) => (w >>> shift) | (w << (32 - shift))
+
+/**
+ * Helper for SHA-224 & SHA-256. See 4.1.2.
+ * @param {number} x
+ */
+const sum0to256 = x => rotr(x, 2) ^ rotr(x, 13) ^ rotr(x, 22)
+
+/**
+ * Helper for SHA-224 & SHA-256. See 4.1.2.
+ * @param {number} x
+ */
+const sum1to256 = x => rotr(x, 6) ^ rotr(x, 11) ^ rotr(x, 25)
+
+/**
+ * Helper for SHA-224 & SHA-256. See 4.1.2.
+ * @param {number} x
+ */
+const sigma0to256 = x => rotr(x, 7) ^ rotr(x, 18) ^ x >>> 3
+
+/**
+ * Helper for SHA-224 & SHA-256. See 4.1.2.
+ * @param {number} x
+ */
+const sigma1to256 = x => rotr(x, 17) ^ rotr(x, 19) ^ x >>> 10
+
 // @todo don't init these variables globally
 
 /**
@@ -26,6 +56,7 @@ const K = new Uint32Array([
   0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
   0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208, 0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2
 ])
+
 /**
  * See 5.3.3. Initial hash value.
  *
@@ -111,8 +142,8 @@ const updateHash = (H, W, K) => {
   let h = H[7]
   // Step 3
   for (let t = 0; t < 64; t++) {
-    const T1 = (h + sum1to256(e) + ch(e, f, g) + K[t] + W[t]) >>> 0
-    const T2 = (sum0to256(a) + maj(a, b, c)) >>> 0
+    const T1 = (h + sum1to256(e) + ((e & f) ^ (~e & g)) + K[t] + W[t]) >>> 0
+    const T2 = (sum0to256(a) + ((a & b) ^ (a & c) ^ (b & c))) >>> 0
     h = g
     g = f
     f = e
@@ -131,47 +162,3 @@ const updateHash = (H, W, K) => {
   H[6] += g
   H[7] += h
 }
-
-/**
- * @param {number} x
- * @param {number} y
- * @param {number} z
- */
-const ch = (x, y, z) => (x & y) ^ (~x & z)
-
-/**
- * @param {number} x
- * @param {number} y
- * @param {number} z
- */
-const maj = (x, y, z) => (x & y) ^ (x & z) ^ (y & z)
-
-/**
- * @param {number} w - a 32bit uint
- * @param {number} shift
- */
-const rotr = (w, shift) => (w >>> shift) | (w << (32 - shift))
-
-/**
- * Helper for SHA-224 & SHA-256. See 4.1.2.
- * @param {number} x
- */
-const sum0to256 = x => rotr(x, 2) ^ rotr(x, 13) ^ rotr(x, 22)
-
-/**
- * Helper for SHA-224 & SHA-256. See 4.1.2.
- * @param {number} x
- */
-const sum1to256 = x => rotr(x, 6) ^ rotr(x, 11) ^ rotr(x, 25)
-
-/**
- * Helper for SHA-224 & SHA-256. See 4.1.2.
- * @param {number} x
- */
-const sigma0to256 = x => rotr(x, 7) ^ rotr(x, 18) ^ x >>> 3
-
-/**
- * Helper for SHA-224 & SHA-256. See 4.1.2.
- * @param {number} x
- */
-const sigma1to256 = x => rotr(x, 17) ^ rotr(x, 19) ^ x >>> 10
diff --git a/hash/sha256.node.js b/hash/sha256.node.js
new file mode 100644
index 0000000..37e3d78
--- /dev/null
+++ b/hash/sha256.node.js
@@ -0,0 +1,10 @@
+import { createHash } from 'node:crypto'
+
+/**
+ * @param {Uint8Array} data
+ */
+export const hash = data => {
+  const hasher = createHash('sha256')
+  hasher.update(data)
+  return hasher.digest()
+}
diff --git a/hash/sha256.test.js b/hash/sha256.test.js
index 056446e..78af201 100644
--- a/hash/sha256.test.js
+++ b/hash/sha256.test.js
@@ -1,10 +1,11 @@
 import * as t from '../testing.js'
-import * as sha256 from './sha256.js'
+import * as sha256 from './sha256.fallback.js'
 import * as buffer from '../buffer.js'
 import * as string from '../string.js'
 import * as prng from '../prng.js'
 import * as webcrypto from 'lib0/webcrypto'
 import * as promise from '../promise.js'
+import * as env from '../environment.js'
 
 /**
  * @param {t.TestCase} _tc
@@ -56,12 +57,21 @@ export const testBenchmarkSha256 = async _tc => {
     webcrypto.getRandomValues(data)
     datas.push(data)
   }
-  t.measureTime(`[lib0] Time to hash ${N} random values of size ${BS}`, () => {
+  t.measureTime(`[lib0 (fallback))] Time to hash ${N} random values of size ${BS}`, () => {
     for (let i = 0; i < N; i++) {
       const x = sha256.hash(datas[i])
       if (x === null) throw new Error()
     }
   })
+  if (env.isNode) {
+    const nodeSha = await import('./sha256.node.js')
+    t.measureTime(`[lib0 (node))] Time to hash ${N} random values of size ${BS}`, () => {
+      for (let i = 0; i < N; i++) {
+        const x = nodeSha.hash(datas[i])
+        if (x === null) throw new Error()
+      }
+    })
+  }
   t.measureTime(`[webcrypto sequentially] Time to hash ${N} random values of size ${BS}`, async () => {
     for (let i = 0; i < N; i++) {
       const x = await webcrypto.subtle.digest('SHA-256', datas[i])
diff --git a/package.json b/package.json
index c4be3d7..ce2b335 100644
--- a/package.json
+++ b/package.json
@@ -103,6 +103,18 @@
       "import": "./hash/rabin.js",
       "require": "./dist/rabin.cjs"
     },
+    "./hash/sha256": {
+      "types": "./hash/sha256.fallback.d.ts",
+      "node": {
+        "require": "./dist/sha256.node.cjs",
+        "default": "./hash/sha256.node.js"
+      },
+      "default": {
+        "module": "./hash/sha256.fallback.js"
+        "require": "./dist/sha256.fallback.cjs",
+        "default": "./hash/sha256.fallback.js"
+      }
+    },
     "./decoding.js": "./decoding.js",
     "./dist/decoding.cjs": "./dist/decoding.cjs",
     "./decoding": {