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Revert "Revert "add chacha20""

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This reverts commit 2012e6d3a8.
This commit is contained in:
Jeff Becker 2017-01-29 17:21:37 -05:00
parent c5fa3ad4a2
commit 8521d0d490
2 changed files with 120 additions and 5 deletions
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9
build-js.sh
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@ -65,11 +65,10 @@ echo "building nntpchan.js ..."
echo
initfile "$outfile"
if [ -e ./contrib/js/contrib/*.js ] ; then
for f in ./contrib/js/contrib/*.js ; do
mini "$f" "$outfile"
done
fi
for f in ./contrib/js/contrib/*.js ; do
mini "$f" "$outfile"
done
mini ./contrib/js/entry.js "$outfile"

116
contrib/js/contrib/chacha20.js Normal file
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@ -0,0 +1,116 @@
/* chacha20 - 256 bits */
// Written in 2014 by Devi Mandiri. Public domain.
//
// Implementation derived from chacha-ref.c version 20080118
// See for details: http://cr.yp.to/chacha/chacha-20080128.pdf
function U8TO32_LE(x, i) {
return x[i] | (x[i+1]<<8) | (x[i+2]<<16) | (x[i+3]<<24);
}
function U32TO8_LE(x, i, u) {
x[i] = u; u >>>= 8;
x[i+1] = u; u >>>= 8;
x[i+2] = u; u >>>= 8;
x[i+3] = u;
}
function ROTATE(v, c) {
return (v << c) | (v >>> (32 - c));
}
var Chacha20 = function(key, nonce, counter) {
this.input = new Uint32Array(16);
// https://tools.ietf.org/html/draft-irtf-cfrg-chacha20-poly1305-01#section-2.3
this.input[0] = 1634760805;
this.input[1] = 857760878;
this.input[2] = 2036477234;
this.input[3] = 1797285236;
this.input[4] = U8TO32_LE(key, 0);
this.input[5] = U8TO32_LE(key, 4);
this.input[6] = U8TO32_LE(key, 8);
this.input[7] = U8TO32_LE(key, 12);
this.input[8] = U8TO32_LE(key, 16);
this.input[9] = U8TO32_LE(key, 20);
this.input[10] = U8TO32_LE(key, 24);
this.input[11] = U8TO32_LE(key, 28);
// be compatible with the reference ChaCha depending on the nonce size
if(nonce.length == 12)
{
this.input[12] = counter;
this.input[13] = U8TO32_LE(nonce, 0);
this.input[14] = U8TO32_LE(nonce, 4);
this.input[15] = U8TO32_LE(nonce, 8);
}else{
this.input[12] = counter;
this.input[13] = 0;
this.input[14] = U8TO32_LE(nonce, 0);
this.input[15] = U8TO32_LE(nonce, 4);
}
};
Chacha20.prototype.quarterRound = function(x, a, b, c, d) {
x[a] += x[b]; x[d] = ROTATE(x[d] ^ x[a], 16);
x[c] += x[d]; x[b] = ROTATE(x[b] ^ x[c], 12);
x[a] += x[b]; x[d] = ROTATE(x[d] ^ x[a], 8);
x[c] += x[d]; x[b] = ROTATE(x[b] ^ x[c], 7);
};
Chacha20.prototype.encrypt = function(dst, src, len) {
var x = new Uint32Array(16);
var output = new Uint8Array(64);
var i, dpos = 0, spos = 0;
while (len > 0 ) {
for (i = 16; i--;) x[i] = this.input[i];
for (i = 20; i > 0; i -= 2) {
this.quarterRound(x, 0, 4, 8,12);
this.quarterRound(x, 1, 5, 9,13);
this.quarterRound(x, 2, 6,10,14);
this.quarterRound(x, 3, 7,11,15);
this.quarterRound(x, 0, 5,10,15);
this.quarterRound(x, 1, 6,11,12);
this.quarterRound(x, 2, 7, 8,13);
this.quarterRound(x, 3, 4, 9,14);
}
for (i = 16; i--;) x[i] += this.input[i];
for (i = 16; i--;) U32TO8_LE(output, 4*i, x[i]);
this.input[12] += 1;
if (!this.input[12]) {
this.input[13] += 1;
}
if (len <= 64) {
for (i = len; i--;) {
dst[i+dpos] = src[i+spos] ^ output[i];
}
return;
}
for (i = 64; i--;) {
dst[i+dpos] = src[i+spos] ^ output[i];
}
len -= 64;
spos += 64;
dpos += 64;
}
};
Chacha20.prototype.keystream = function(dst, len) {
for (var i = 0; i < len; ++i) dst[i] = 0;
this.encrypt(dst, dst, len);
};
// additions to make it easier and export it as a module
exports.Cipher = Chacha20;
exports.encrypt = exports.decrypt = function(key, nonce, data)
{
var cipher = new Chacha20(key, nonce);
var ret = new Buffer(data.length);
cipher.encrypt(ret, data, data.length);
return ret;
}