MASK=0xffffffff;

function int2bytes(x){
	var res=new Array(4);
	for(var i=0;i<4;i++){
		res[i]=x&0xff;
		x>>>=8;
	}
	return res;
}

function lrot(x,shift){
	return (x<<shift|x>>>(32-shift))&MASK;
}

function quarterRound(arr,ia,ib,ic,id){
	var a=arr[ia], b=arr[ib], c=arr[ic], d=arr[id];
	a=(a+b)&MASK; d=lrot(d^a,16);
	c=(c+d)&MASK; b=lrot(b^c,12);
	a=(a+b)&MASK; d=lrot(d^a,8);
	c=(c+d)&MASK; b=lrot(b^c,7);
	arr[ia]=a; arr[ib]=b; arr[ic]=c; arr[id]=d;
}

function chacha(key,nonce,position){
	var x=input.slice();

	for(var i=0;i<10;i++){
		// column round
		quarterRound(x,0,4,8,12);
		quarterRound(x,1,5,9,13);
		quarterRound(x,2,6,10,14);
		quarterRound(x,3,7,11,15);
		// diagonal round
		quarterRound(x,0,5,10,15);
		quarterRound(x,1,6,11,12);
		quarterRound(x,2,7,8,13);
		quarterRound(x,3,4,9,14);
	}

	return x.map((xi,i)=>(xi+input[i])&MASK);
}

function encrypt(message,key){
	var nonce=Date.now();
	var nonce0=nonce;
}