Changeset - 12f10d9d5948
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Laman - 5 years ago 2019-07-05 15:42:03

refactored Chacha20.encrypt, .decrypt
4 files changed with 22 insertions and 22 deletions:
spec/test/chachaSpec.js
3
2
src/chacha.js
6
13
src/main.js
7
7
src/util.js
6
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spec/test/chachaSpec.js
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@@ -25,28 +25,29 @@ describe("Chacha",function(){
 
			let cipher=new Chacha20(key,nonce2);
 
			let expected=[34,79,81,243,64,27,217,225,47,222,39,111,184,99,29,237,140,19,31,130,61,44,6, 226,126,79,202,236,158,243,207,120,138,59,10,163,114,96,10,146,181,121,116,205,237,43,147,52,121, 76,186,64,198,62,52,205,234,33,44,76,240,125,65,183,105,166,116,159,63,99,15,65,34,202,254,40,236, 77,196,126,38,212,52,109,112,185,140,115,243,233,197,58,196,12,89,69,57,139,110,218,26,131,44,137, 193,103,234,205,144,29,126,43,243,99];
 
			expected.forEach(b=>{
 
				expect(cipher.getByte()).toEqual(b);
 
			});
 
		});
 
 
	});
 
 
	describe("encrypt",function(){
 
		it("should correctly encrypt an example text",function(){
 
			let ciphertext=[110,46,53,154,37,104,249,128,65,186,7,40,221,13,105,129,233,126,122,236,29, 67,96,194,10,39,175,204,253,159,174,11,249,27,101,197,82,71,51,171,143,89,61,171,205,98,179,87,22, 57,214,36,230,81,82,171,143,83,12,53,159,8,97,216,7,202,13,191,80,13,106,97,86,163,142,8,138,34, 182,94,82,188,81,77,22,204,248,6,129,140,233,26,183,121,55,54,90,249,11,191,116,163,91,230,180,11, 142,237,242,120,94,66,135,77];
 
			expect(encrypt(str2utf8(plaintext),key,nonce2)).toEqual(nonce2.concat(ciphertext));
 
			expect(encrypt(str2utf8(plaintext),key,nonce2)).toEqual([nonce2,ciphertext]);
 
		});
 
	});
 
 
	describe("decrypt",function(){
 
		it("should be able to decrypt a Chacha20 encrypted text",function(){
 
			let text=str2utf8(plaintext);
 
			let key=[];
 
			for(let i=0;i<16;i++){key.push(Math.floor(Math.random()*256));}
 
			let nonce=[];
 
			for(let i=0;i<8;i++){nonce.push(Math.floor(Math.random()*256));}
 
			expect(decrypt(encrypt(text,key,nonce),key)).toEqual(text);
 
			let [_,ciphertext]=encrypt(text,key,nonce);
 
			expect(decrypt(ciphertext,key,nonce)).toEqual(text);
 
		});
 
	});
 
 
});
src/chacha.js
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// https://tools.ietf.org/html/rfc7539
 
import {MASK,int32s2bytes,bytes2int32s,zeroPad} from "./util.js";
 
import {MASK,int32s2bytes,bytes2int32s,zeroPad,createRandomNonce} from "./util.js";
 

			




	
	
	
		
 
function lrot(x,shift){

			




	
	
	
		
 
	return (x<<shift|x>>>(32-shift))&MASK;

			




	
	
	
		
 
}

			




	
	
	
		
 

			




	
	
	
		
 
export function createNonce(){

			




	
	
	
		
 
	let nonce=new Uint8Array(12);

			




	
	
	
		
 
	window.crypto.getRandomValues(nonce);

			




	
	
	
		
 
	return Array.from(nonce);

			




	
	
	
		
 
}

			




	
	
	
		
 

			




	
	
	
		
 
/**

			




	
	
	
		
 
 * A Chacha20 cipher class.

			




	
	
	
		
 
 * @param {Array} key Array of bytes (integers: 0<=x<256). Short keys are padded to 32B, long keys are silently truncated.

			




	
	
	
		
 
 * @param {Array} nonce optional. If present, it must be an Array of bytes (integers: 0<=x<256). Short nonces are padded to 12B, long nonces are silently truncated.

			




	
	
	
		
 
 */

			




	
	
	
		
 
export function Chacha20(key,nonce){

			




	
	
	
		
 
	const NONCE_LEN=12;

			




	
	
	
		
 
	if(nonce===undefined){

			




	
	
	
		
 
		nonce=createNonce();

			




	
	
	
		
 
		nonce=createRandomNonce(NONCE_LEN);

			




	
	
	
		
 
	}

			




	
	
	
		
 
	this._nonce=zeroPad(nonce,12);

			




	
	
	
		
 
	this._nonce=zeroPad(nonce,NONCE_LEN);

			




	
	
	
		
 
	nonce=bytes2int32s(this._nonce);

			




	
	
	
		
 
	key=bytes2int32s(zeroPad(key,32));

			




	
	
	
		
 
	

			




	
	
	
		
 
	this._state=[

			




	
	
	
		
 
		0x61707865,0x3320646e,0x79622d32,0x6b206574,

			




	
	
	
		
 
		key[0],key[1],key[2],key[3],

			




	
	
	
		
 
		key[4],key[5],key[6],key[7],

			




	
	
	
		
 
		1,nonce[0],nonce[1],nonce[2]

			




	
	
	
		
 
	];

			




	
	
	
		
 
	this._buffer=[];

			




	
	
	
		
 
}

			




	
	
	
		
 

			




	
	
		
 
@@ -76,21 +71,19 @@ Chacha20.prototype._computeBlock=functio

			




	
	
	
		
 
	}

			




	
	
	
		
 

			




	
	
	
		
 
	return state.map((xi,i)=>(xi+this._state[i])&MASK);

			




	
	
	
		
 
};

			




	
	
	
		
 

			




	
	
	
		
 
Chacha20.prototype._incrementPos=function(){

			




	
	
	
		
 
	this._state[12]=(this._state[12]+1)&MASK;

			




	
	
	
		
 
};

			




	
	
	
		
 

			




	
	
	
		
 
export function encrypt(data,key,nonce){

			




	
	
	
		
 
	let cipher=new Chacha20(key,nonce);

			




	
	
	
		
 
	nonce=cipher.getNonce();

			




	
	
	
		
 
	return nonce.concat(data.map(b=>b^cipher.getByte()));

			




	
	
	
		
 
	return [nonce,data.map(b=>b^cipher.getByte())];

			




	
	
	
		
 
}

			




	
	
	
		
 

			




	
	
	
		
 
export function decrypt(data,key){

			




	
	
	
		
 
	let nonce=data.slice(0,12);

			




	
	
	
		
 
	let ciphertext=data.slice(12);

			




	
	
	
		
 
export function decrypt(ciphertext,key,nonce){

			




	
	
	
		
 
	let cipher=new Chacha20(key,nonce);

			




	
	
	
		
 
	return ciphertext.map(b=>b^cipher.getByte());

			




	
	
	
		
 
}

			




        

    


    
    

    

        

                

                    src/main.js
                

                

                  
                      
                        

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import * as util from "./util.js";

			




	
	
	
		
 
import {blake2s} from "./blake.js";

			




	
	
	
		
 
import {pbkdf2} from "./pbkdf2.js";

			




	
	
	
		
 
import {createNonce,Chacha20,encrypt as _encrypt,decrypt as _decrypt} from "./chacha.js";

			




	
	
	
		
 
import {Chacha20,encrypt as _encrypt,decrypt as _decrypt} from "./chacha.js";

			




	
	
	
		
 

			




	
	
	
		
 
const VERSION=1;

			




	
	
	
		
 

			




	
	
	
		
 
function encrypt(s,password){

			




	
	
	
		
 
	let bs=util.str2utf8(s);

			




	
	
	
		
 
	let pass=util.str2utf8(password);

			




	
	
	
		
 
	let salt=createNonce();

			




	
	
	
		
 
	let salt=util.createRandomNonce(12);

			




	
	
	
		
 
	let [iters,key]=stretchKey(pass,salt);

			




	
	
	
		
 
	let noncedCiphertext=_encrypt(bs,key,salt);

			




	
	
	
		
 
	let payload=[iters].concat(noncedCiphertext);

			




	
	
	
		
 
	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);

			




	
	
	
		
 
	return util.bytes2base64(arr);

			




	
	
	
		
 
}

			




	
	
	
		
 

			




	
	
	
		
 
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 salt=arr.slice(18,30);

			




	
	
	
		
 
	let noncedCiphertext=arr.slice(18);

			




	
	
	
		
 
	let check=blake2s([version].concat([iters],noncedCiphertext),16,pass);

			




	
	
	
		
 
	let ciphertext=arr.slice(30);

			




	
	
	
		
 
	let check=blake2s([version,iters].concat(salt,ciphertext),16,pass);

			




	
	
	
		
 
	if(!signature.every((b,i)=>b===check[i])){return false;}

			




	
	
	
		
 
	if(version>VERSION){return false;}

			




	
	
	
		
 
	let key=pbkdf2(pass,salt,1<<iters,32);

			




	
	
	
		
 
	let plainbytes=_decrypt(noncedCiphertext,key);

			




	
	
	
		
 
	let plainbytes=_decrypt(ciphertext,key,salt);

			




	
	
	
		
 
	return util.utf82str(plainbytes);

			




	
	
	
		
 
}

			




	
	
	
		
 

			




	
	
	
		
 
function stretchKey(password,salt){

			




	
	
	
		
 
	let start=Date.now(); // ms

			




	
	
	
		
 
	let i,key;

			




	
	
	
		
 
	for(i=0;i<256;i++){

			




	
	
	
		
 
		key=pbkdf2(password,salt,1<<i,32);

			




	
	
	
		
 
		if(Date.now()-start>=500){break;}

			




	
	
	
		
 
	}

			




	
	
	
		
 
	return [i,key];

			




	
	
	
		
 
}

			




        

    


    
    

    

        

                

                    src/util.js
                

                

                  
                      
                        

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@@ -129,12 +129,18 @@ export function base642bytes(str){

			




	
	
	
		
 
		let b3=remapping[str.charCodeAt(i+2)];

			




	
	
	
		
 
		let b4=remapping[str.charCodeAt(i+3)];

			




	
	
	
		
 
		

			




	
	
	
		
 
		out.push((b1<<2)+(b2>>4&3));

			




	
	
	
		
 
		out.push(((b2&15)<<4)+(b3>>2&15));

			




	
	
	
		
 
		out.push(((b3&3)<<6)+b4);

			




	
	
	
		
 
	}

			




	
	
	
		
 
	

			




	
	
	
		
 
	for(let i=1; i<3&&str[str.length-i]=="="; i++){out.pop();}

			




	
	
	
		
 

			




	
	
	
		
 
	return out;

			




	
	
	
		
 
}

			




	
	
	
		
 

			




	
	
	
		
 
export function createRandomNonce(n){

			




	
	
	
		
 
	let nonce=new Uint8Array(n);

			




	
	
	
		
 
	window.crypto.getRandomValues(nonce);

			




	
	
	
		
 
	return Array.from(nonce);

			




	
	
	
		
 
}

			




        

    



    


    



    



      

      





    
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