[Pkg-javascript-commits] [node-browserify-aes] 23/43: aes: G does not need to be prototyped

[Bastien Roucariès]

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rouca pushed a commit to branch master
in repository node-browserify-aes.

commit b17f514a49c9652f9d1911bec273ccf7063ac9c9
Author: Daniel Cousens <github at dcousens.com>
Date:   Fri May 19 12:59:58 2017 +1000

    aes: G does not need to be prototyped
---
 aes.js | 95 +++++++++++++++++++++++++++++++++++-------------------------------
 1 file changed, 51 insertions(+), 44 deletions(-)

diff --git a/aes.js b/aes.js
index 997ef4c..a0f59ef 100644
--- a/aes.js
+++ b/aes.js
@@ -23,49 +23,52 @@ function scrubVec (v) {
   }
 }
 
-function Global () {
-  this.SBOX = []
-  this.INV_SBOX = []
-  this.SUB_MIX = [[], [], [], []]
-  this.INV_SUB_MIX = [[], [], [], []]
-  this.init()
-  this.RCON = [0x00, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36]
-}
-
-Global.prototype.init = function () {
-  var d, i, sx, t, x, x2, x4, x8, xi, _i
-  d = (function () {
-    var _i, _results
-    _results = []
-    for (i = _i = 0; _i < 256; i = ++_i) {
-      if (i < 128) {
-        _results.push(i << 1)
-      } else {
-        _results.push((i << 1) ^ 0x11b)
-      }
+var RCON = [0x00, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36]
+var G = (function () {
+  // Compute double table
+  var d = new Array(256)
+  for (var j = 0; j < 256; j++) {
+    if (j < 128) {
+      d[j] = j << 1
+    } else {
+      d[j] = (j << 1) ^ 0x11b
     }
-    return _results
-  })()
-  x = 0
-  xi = 0
-  for (i = _i = 0; _i < 256; i = ++_i) {
-    sx = xi ^ (xi << 1) ^ (xi << 2) ^ (xi << 3) ^ (xi << 4)
+  }
+
+  var SBOX = []
+  var INV_SBOX = []
+  var SUB_MIX = [[], [], [], []]
+  var INV_SUB_MIX = [[], [], [], []]
+
+  // Walk GF(2^8)
+  var x = 0
+  var xi = 0
+  for (var i = 0; i < 256; ++i) {
+    // Compute sbox
+    var sx = xi ^ (xi << 1) ^ (xi << 2) ^ (xi << 3) ^ (xi << 4)
     sx = (sx >>> 8) ^ (sx & 0xff) ^ 0x63
-    this.SBOX[x] = sx
-    this.INV_SBOX[sx] = x
-    x2 = d[x]
-    x4 = d[x2]
-    x8 = d[x4]
-    t = (d[sx] * 0x101) ^ (sx * 0x1010100)
-    this.SUB_MIX[0][x] = (t << 24) | (t >>> 8)
-    this.SUB_MIX[1][x] = (t << 16) | (t >>> 16)
-    this.SUB_MIX[2][x] = (t << 8) | (t >>> 24)
-    this.SUB_MIX[3][x] = t
+    SBOX[x] = sx
+    INV_SBOX[sx] = x
+
+    // Compute multiplication
+    var x2 = d[x]
+    var x4 = d[x2]
+    var x8 = d[x4]
+
+    // Compute sub bytes, mix columns tables
+    var t = (d[sx] * 0x101) ^ (sx * 0x1010100)
+    SUB_MIX[0][x] = (t << 24) | (t >>> 8)
+    SUB_MIX[1][x] = (t << 16) | (t >>> 16)
+    SUB_MIX[2][x] = (t << 8) | (t >>> 24)
+    SUB_MIX[3][x] = t
+
+    // Compute inv sub bytes, inv mix columns tables
     t = (x8 * 0x1010101) ^ (x4 * 0x10001) ^ (x2 * 0x101) ^ (x * 0x1010100)
-    this.INV_SUB_MIX[0][sx] = (t << 24) | (t >>> 8)
-    this.INV_SUB_MIX[1][sx] = (t << 16) | (t >>> 16)
-    this.INV_SUB_MIX[2][sx] = (t << 8) | (t >>> 24)
-    this.INV_SUB_MIX[3][sx] = t
+    INV_SUB_MIX[0][sx] = (t << 24) | (t >>> 8)
+    INV_SUB_MIX[1][sx] = (t << 16) | (t >>> 16)
+    INV_SUB_MIX[2][sx] = (t << 8) | (t >>> 24)
+    INV_SUB_MIX[3][sx] = t
+
     if (x === 0) {
       x = xi = 1
     } else {
@@ -73,10 +76,14 @@ Global.prototype.init = function () {
       xi ^= d[d[xi]]
     }
   }
-  return true
-}
 
-var G = new Global()
+  return {
+    SBOX: SBOX,
+    INV_SBOX: INV_SBOX,
+    SUB_MIX: SUB_MIX,
+    INV_SUB_MIX: INV_SUB_MIX
+  }
+})()
 
 AES.blockSize = 4 * 4
 
@@ -104,7 +111,7 @@ AES.prototype._doReset = function () {
   }
 
   for (k = keySize; k < ksRows; k++) {
-    this._keySchedule[k] = (t = this._keySchedule[k - 1], (k % keySize) === 0 ? (t = (t << 8) | (t >>> 24), t = (G.SBOX[t >>> 24] << 24) | (G.SBOX[(t >>> 16) & 0xff] << 16) | (G.SBOX[(t >>> 8) & 0xff] << 8) | G.SBOX[t & 0xff], t ^= G.RCON[(k / keySize) | 0] << 24) : keySize > 6 && k % keySize === 4 ? t = (G.SBOX[t >>> 24] << 24) | (G.SBOX[(t >>> 16) & 0xff] << 16) | (G.SBOX[(t >>> 8) & 0xff] << 8) | G.SBOX[t & 0xff] : void 0, this._keySchedule[k - keySize] ^ t)
+    this._keySchedule[k] = (t = this._keySchedule[k - 1], (k % keySize) === 0 ? (t = (t << 8) | (t >>> 24), t = (G.SBOX[t >>> 24] << 24) | (G.SBOX[(t >>> 16) & 0xff] << 16) | (G.SBOX[(t >>> 8) & 0xff] << 8) | G.SBOX[t & 0xff], t ^= RCON[(k / keySize) | 0] << 24) : keySize > 6 && k % keySize === 4 ? t = (G.SBOX[t >>> 24] << 24) | (G.SBOX[(t >>> 16) & 0xff] << 16) | (G.SBOX[(t >>> 8) & 0xff] << 8) | G.SBOX[t & 0xff] : void 0, this._keySchedule[k - keySize] ^ t)
   }
 
   var invKeySchedule = []

-- 
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