diff --git a/util.js b/util.js
--- a/util.js
+++ b/util.js
@@ -1,4 +1,33 @@
-export function str2utf8(s){
+function bytes2int32(arr){
+	return arr.reduce((acc,b,i)=>acc|b<<(i*8));
+}
+
+function bytes2int32s(arr){
+	let res=[];
+	for(let i=0;i<arr.length;i+=4){
+		res.push(bytes2int32(arr.slice(i,i+4)));
+	}
+	return res;
+}
+
+function int322bytes(x){
+	let res=[];
+	for(let i=0;i<4;i++){
+		res.push(x&0xff);
+		x>>>=8;
+	}
+	return res;
+}
+
+function int32s2bytes(arr){
+	return arr.map(int322bytes).reduce((acc,bytes)=>acc.concat(bytes));
+}
+
+function bytes2hex(arr){
+	return arr.map(x=>x.toString(16).padStart(2,"0")).join("");
+}
+
+function str2utf8(s){
 	let res=[];
 	let c=s.codePointAt(0);
 	for(let i=0;c!==undefined;i++,c=s.codePointAt(i)){
@@ -23,7 +52,7 @@ export function str2utf8(s){
 	return res;
 }
 
-console.log(str2utf8("$").map(x=>x.toString(16)));
+/*console.log(str2utf8("$").map(x=>x.toString(16)));
 console.log(str2utf8("¢").map(x=>x.toString(16)));
 console.log(str2utf8("€").map(x=>x.toString(16)));
-console.log(str2utf8("𐍈").map(x=>x.toString(16)));
+console.log(str2utf8("𐍈").map(x=>x.toString(16)));*/