--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/nss/lib/freebl/chacha20/chacha20.c	Mon Jul 28 10:47:06 2014 +0200
@@ -0,0 +1,108 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* Adopted from the public domain code in NaCl by djb. */
+
+#include <string.h>
+#include <stdio.h>
+
+#include "prtypes.h"
+#include "chacha20.h"
+
+#define ROTL32(v, n) (((v) << (n)) | ((v) >> (32 - (n))))
+#define ROTATE(v, c) ROTL32((v), (c))
+#define XOR(v, w) ((v) ^ (w))
+#define PLUS(x, y) ((x) + (y))
+
+#define U32TO8_LITTLE(p, v) \
+	{ (p)[0] = ((v)      ) & 0xff; (p)[1] = ((v) >>  8) & 0xff; \
+	  (p)[2] = ((v) >> 16) & 0xff; (p)[3] = ((v) >> 24) & 0xff; }
+#define U8TO32_LITTLE(p)   \
+	(((PRUint32)((p)[0])      ) | ((PRUint32)((p)[1]) <<  8) | \
+	 ((PRUint32)((p)[2]) << 16) | ((PRUint32)((p)[3]) << 24)   )
+
+#define QUARTERROUND(a,b,c,d) \
+  x[a] = PLUS(x[a],x[b]); x[d] = ROTATE(XOR(x[d],x[a]),16); \
+  x[c] = PLUS(x[c],x[d]); x[b] = ROTATE(XOR(x[b],x[c]),12); \
+  x[a] = PLUS(x[a],x[b]); x[d] = ROTATE(XOR(x[d],x[a]), 8); \
+  x[c] = PLUS(x[c],x[d]); x[b] = ROTATE(XOR(x[b],x[c]), 7);
+
+static void ChaChaCore(unsigned char output[64], const PRUint32 input[16],
+		       int num_rounds) {
+    PRUint32 x[16];
+    int i;
+
+    memcpy(x, input, sizeof(PRUint32) * 16);
+    for (i = num_rounds; i > 0; i -= 2) {
+	QUARTERROUND( 0, 4, 8,12)
+	QUARTERROUND( 1, 5, 9,13)
+	QUARTERROUND( 2, 6,10,14)
+	QUARTERROUND( 3, 7,11,15)
+	QUARTERROUND( 0, 5,10,15)
+	QUARTERROUND( 1, 6,11,12)
+	QUARTERROUND( 2, 7, 8,13)
+	QUARTERROUND( 3, 4, 9,14)
+    }
+
+    for (i = 0; i < 16; ++i) {
+	x[i] = PLUS(x[i], input[i]);
+    }
+    for (i = 0; i < 16; ++i) {
+	U32TO8_LITTLE(output + 4 * i, x[i]);
+    }
+}
+
+static const unsigned char sigma[16] = "expand 32-byte k";
+
+void ChaCha20XOR(unsigned char *out, const unsigned char *in, unsigned int inLen,
+		 const unsigned char key[32], const unsigned char nonce[8],
+		 uint64_t counter) {
+    unsigned char block[64];
+    PRUint32 input[16];
+    unsigned int u;
+    unsigned int i;
+
+    input[4] = U8TO32_LITTLE(key + 0);
+    input[5] = U8TO32_LITTLE(key + 4);
+    input[6] = U8TO32_LITTLE(key + 8);
+    input[7] = U8TO32_LITTLE(key + 12);
+
+    input[8] = U8TO32_LITTLE(key + 16);
+    input[9] = U8TO32_LITTLE(key + 20);
+    input[10] = U8TO32_LITTLE(key + 24);
+    input[11] = U8TO32_LITTLE(key + 28);
+
+    input[0] = U8TO32_LITTLE(sigma + 0);
+    input[1] = U8TO32_LITTLE(sigma + 4);
+    input[2] = U8TO32_LITTLE(sigma + 8);
+    input[3] = U8TO32_LITTLE(sigma + 12);
+
+    input[12] = counter;
+    input[13] = counter >> 32;
+    input[14] = U8TO32_LITTLE(nonce + 0);
+    input[15] = U8TO32_LITTLE(nonce + 4);
+
+    while (inLen >= 64) {
+	ChaChaCore(block, input, 20);
+	for (i = 0; i < 64; i++) {
+	    out[i] = in[i] ^ block[i];
+	}
+
+	input[12]++;
+	if (input[12] == 0) {
+	    input[13]++;
+	}
+
+	inLen -= 64;
+	in += 64;
+	out += 64;
+    }
+
+    if (inLen > 0) {
+	ChaChaCore(block, input, 20);
+	for (i = 0; i < inLen; i++) {
+	    out[i] = in[i] ^ block[i];
+	}
+    }
+}