diff --git a/src/main.js b/src/main.js
--- a/src/main.js
+++ b/src/main.js
@@ -11,9 +11,8 @@ function encrypt(s,password){
 	let salt=util.createRandomNonce(12);
 	let [iters,key]=stretchKey(pass,salt);
 	let [_,ciphertext]=_encrypt(bs,key,salt);
-	let payload=[iters].concat(salt,ciphertext);
-	let signature=blake2s([VERSION].concat(payload),16,pass);
-	let arr=[VERSION].concat(signature,payload);
+	let signature=blake2s([VERSION,iters].concat(salt,ciphertext),16,key);
+	let arr=[VERSION,iters].concat(signature,salt,ciphertext);
 	return util.bytes2base64(arr);
 }
 
@@ -21,14 +20,15 @@ function decrypt(s,password){
 	let pass=util.str2utf8(password);
 	let arr=util.base642bytes(s);
 	let version=arr[0];
-	let signature=arr.slice(1,17);
-	let iters=arr[17];
+	let iters=arr[1];
+	let signature=arr.slice(2,18);
 	let salt=arr.slice(18,30);
 	let ciphertext=arr.slice(30);
-	let check=blake2s([version,iters].concat(salt,ciphertext),16,pass);
+	
+	let key=pbkdf2(pass,salt,1<<iters,32);
+	let check=blake2s([version,iters].concat(salt,ciphertext),16,key);
 	if(!signature.every((b,i)=>b===check[i])){return 1;}
 	if(version>VERSION){return 2;}
-	let key=pbkdf2(pass,salt,1<<iters,32);
 	let plainbytes=_decrypt(ciphertext,key,salt);
 	return util.utf82str(plainbytes);
 }