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diff --git a/srp/prng4.js b/srp/prng4.js
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+/*
+ * Copyright (c) 2003-2005  Tom Wu
+ * All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND, 
+ * EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY 
+ * WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.  
+ *
+ * IN NO EVENT SHALL TOM WU BE LIABLE FOR ANY SPECIAL, INCIDENTAL,
+ * INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND, OR ANY DAMAGES WHATSOEVER
+ * RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER OR NOT ADVISED OF
+ * THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF LIABILITY, ARISING OUT
+ * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ * In addition, the following condition applies:
+ *
+ * All redistributions must retain an intact copy of this copyright notice
+ * and disclaimer.
+ */
+
+// prng4.js - uses Arcfour as a PRNG
+
+function Arcfour() {
+  this.i = 0;
+  this.j = 0;
+  this.S = new Array();
+}
+
+// Initialize arcfour context from key, an array of ints, each from [0..255]
+function ARC4init(key) {
+  var i, j, t;
+  for(i = 0; i < 256; ++i)
+    this.S[i] = i;
+  j = 0;
+  for(i = 0; i < 256; ++i) {
+    j = (j + this.S[i] + key[i % key.length]) & 255;
+    t = this.S[i];
+    this.S[i] = this.S[j];
+    this.S[j] = t;
+  }
+  this.i = 0;
+  this.j = 0;
+}
+
+function ARC4next() {
+  var t;
+  this.i = (this.i + 1) & 255;
+  this.j = (this.j + this.S[this.i]) & 255;
+  t = this.S[this.i];
+  this.S[this.i] = this.S[this.j];
+  this.S[this.j] = t;
+  return this.S[(t + this.S[this.i]) & 255];
+}
+
+Arcfour.prototype.init = ARC4init;
+Arcfour.prototype.next = ARC4next;
+
+// Plug in your RNG constructor here
+function prng_newstate() {
+  return new Arcfour();
+}
+
+// Pool size must be a multiple of 4 and greater than 32.
+// An array of bytes the size of the pool will be passed to init()
+var rng_psize = 256;