Fully end to end encrypted anonymous chat program. Server only stores public key lookup for users and the encrypted messages. No credentials are transfered to the server, but kept in local browser storage. This allows 100% safe chatting. https://safechat.ch
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var Buffer = require('buffer').Buffer;
var Crypto = require('crypto');
var Auth = exports;
function sha1(msg) {
var hash = Crypto.createHash('sha1');
hash.update(msg, 'binary');
return hash.digest('binary');
}
Auth.sha1 = sha1;
function xor(a, b) {
a = new Buffer(a, 'binary');
b = new Buffer(b, 'binary');
var result = new Buffer(a.length);
for (var i = 0; i < a.length; i++) {
result[i] = (a[i] ^ b[i]);
}
return result;
}
Auth.xor = xor;
Auth.token = function(password, scramble) {
if (!password) {
return new Buffer(0);
}
// password must be in binary format, not utf8
var stage1 = sha1((new Buffer(password, "utf8")).toString("binary"));
var stage2 = sha1(stage1);
var stage3 = sha1(scramble.toString('binary') + stage2);
return xor(stage3, stage1);
};
// This is a port of sql/password.c:hash_password which needs to be used for
// pre-4.1 passwords.
Auth.hashPassword = function(password) {
var nr = [0x5030, 0x5735],
add = 7,
nr2 = [0x1234, 0x5671],
result = new Buffer(8);
if (typeof password == 'string'){
password = new Buffer(password);
}
for (var i = 0; i < password.length; i++) {
var c = password[i];
if (c == 32 || c == 9) {
// skip space in password
continue;
}
// nr^= (((nr & 63)+add)*c)+ (nr << 8);
// nr = xor(nr, add(mul(add(and(nr, 63), add), c), shl(nr, 8)))
nr = this.xor32(nr, this.add32(this.mul32(this.add32(this.and32(nr, [0,63]), [0,add]), [0,c]), this.shl32(nr, 8)));
// nr2+=(nr2 << 8) ^ nr;
// nr2 = add(nr2, xor(shl(nr2, 8), nr))
nr2 = this.add32(nr2, this.xor32(this.shl32(nr2, 8), nr));
// add+=tmp;
add += c;
}
this.int31Write(result, nr, 0);
this.int31Write(result, nr2, 4);
return result;
};
Auth.randomInit = function(seed1, seed2) {
return {
max_value: 0x3FFFFFFF,
max_value_dbl: 0x3FFFFFFF,
seed1: seed1 % 0x3FFFFFFF,
seed2: seed2 % 0x3FFFFFFF
};
};
Auth.myRnd = function(r){
r.seed1 = (r.seed1 * 3 + r.seed2) % r.max_value;
r.seed2 = (r.seed1 + r.seed2 + 33) % r.max_value;
return r.seed1 / r.max_value_dbl;
};
Auth.scramble323 = function(message, password) {
var to = new Buffer(8),
hashPass = this.hashPassword(password),
hashMessage = this.hashPassword(message.slice(0, 8)),
seed1 = this.int32Read(hashPass, 0) ^ this.int32Read(hashMessage, 0),
seed2 = this.int32Read(hashPass, 4) ^ this.int32Read(hashMessage, 4),
r = this.randomInit(seed1, seed2);
for (var i = 0; i < 8; i++){
to[i] = Math.floor(this.myRnd(r) * 31) + 64;
}
var extra = (Math.floor(this.myRnd(r) * 31));
for (var i = 0; i < 8; i++){
to[i] ^= extra;
}
return to;
};
Auth.fmt32 = function(x){
var a = x[0].toString(16),
b = x[1].toString(16);
if (a.length == 1) a = '000'+a;
if (a.length == 2) a = '00'+a;
if (a.length == 3) a = '0'+a;
if (b.length == 1) b = '000'+b;
if (b.length == 2) b = '00'+b;
if (b.length == 3) b = '0'+b;
return '' + a + '/' + b;
};
Auth.xor32 = function(a,b){
return [a[0] ^ b[0], a[1] ^ b[1]];
};
Auth.add32 = function(a,b){
var w1 = a[1] + b[1],
w2 = a[0] + b[0] + ((w1 & 0xFFFF0000) >> 16);
return [w2 & 0xFFFF, w1 & 0xFFFF];
};
Auth.mul32 = function(a,b){
// based on this example of multiplying 32b ints using 16b
// http://www.dsprelated.com/showmessage/89790/1.php
var w1 = a[1] * b[1],
w2 = (((a[1] * b[1]) >> 16) & 0xFFFF) + ((a[0] * b[1]) & 0xFFFF) + (a[1] * b[0] & 0xFFFF);
return [w2 & 0xFFFF, w1 & 0xFFFF];
};
Auth.and32 = function(a,b){
return [a[0] & b[0], a[1] & b[1]];
};
Auth.shl32 = function(a,b){
// assume b is 16 or less
var w1 = a[1] << b,
w2 = (a[0] << b) | ((w1 & 0xFFFF0000) >> 16);
return [w2 & 0xFFFF, w1 & 0xFFFF];
};
Auth.int31Write = function(buffer, number, offset) {
buffer[offset] = (number[0] >> 8) & 0x7F;
buffer[offset + 1] = (number[0]) & 0xFF;
buffer[offset + 2] = (number[1] >> 8) & 0xFF;
buffer[offset + 3] = (number[1]) & 0xFF;
};
Auth.int32Read = function(buffer, offset){
return (buffer[offset] << 24)
+ (buffer[offset+1] << 16)
+ (buffer[offset+2] << 8)
+ (buffer[offset+3]);
};