diff --git a/chacha.js b/chacha.js
--- a/chacha.js
+++ b/chacha.js
@@ -1,47 +1,88 @@
-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;
-}
+// https://tools.ietf.org/html/rfc7539
 
 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];
+function createNonce(){
+	let nonce=new Uint8Array(12);
+	window.crypto.getRandomValues(nonce);
+	return nonce;
+}
+
+function Chacha20(key,nonce){
+	if(nonce===undefined){
+		let nonce=createNonce();
+	}
+	nonce=bytes2int32s(nonce);
+	key=bytes2int32s(key);
+	
+	this._state=[
+		0x61707865,0x3320646e,0x79622d32,0x6b206574,
+		key[0],key[1],key[2],key[3],
+		key[4],key[5],key[6],key[7],
+		0,nonce[0],nonce[1],nonce[2]
+	];
+	this._buffer=[];
+}
+
+Chacha20.prototype.setPos=function(pos){
+	this._state[12]=pos;
+	this._buffer=[];
+}
+
+Chacha20.prototype.getByte=function(){
+	if(this._buffer.length==0){
+		this._buffer=int32s2bytes(this._computeBlock());
+	}
+	return this._buffer.shift();
+};
+
+Chacha20.prototype._quarterRound=function(arr,ia,ib,ic,id){
+	let 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;
+};
+
+Chacha20.prototype._computeBlock=function(){
+	let state=this._state.slice();
+
+	for(let i=0;i<10;i++){ // 10 double rounds
+		// column round
+		this._quarterRound(state,0,4,8,12);
+		this._quarterRound(state,1,5,9,13);
+		this._quarterRound(state,2,6,10,14);
+		this._quarterRound(state,3,7,11,15);
+		// diagonal round
+		this._quarterRound(state,0,5,10,15);
+		this._quarterRound(state,1,6,11,12);
+		this._quarterRound(state,2,7,8,13);
+		this._quarterRound(state,3,4,9,14);
+	}
+
+	return state.map((xi,i)=>(xi+this._state[i])&MASK);
+};
+
+Chacha20.prototype._incrementPos=function(){
+	this._state[12]=(this._state[12]+1)&MASK;
+};
+
+function encrypt(message,key){
+	let nonce=Date.now();
+	let nonce0=nonce;
+	let hashedKey=blake2s(str2bytes(key));
+	message=str2bytes(message);
 }
 
-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 testChacha(){
+	let key=[0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31];
+	let nonce=[0,0,0,9,0,0,0,74,0,0,0,0];
+	let cipher=new Chacha20(key,nonce);
+	cipher.setPos(1);
+	let output=cipher._computeBlock().map(x=>(x>>>0).toString(16).padStart(8,"0"));
+	let example=["e4e7f110","15593bd1","1fdd0f50","c47120a3","c7f4d1c7","0368c033","9aaa2204","4e6cd4c3","466482d2","09aa9f07","05d7c214","a2028bd9","d19c12b5","b94e16de","e883d0cb","4e3c50a2"];
+	console.log(output.every((x,i)=>x==example[i]));
 }
-
-function encrypt(message,key){
-	var nonce=Date.now();
-	var nonce0=nonce;
-}