How to convert hex string into a bytes array, and a bytes array in the hex string?

javascript arrays string hex

79,060

Solution 1

Update: Scroll down for solution... Live Demo

The issue: you are using a lossy conversion to hex, which cannot be reversed.

var p = parseHexString(createHexString(rsa_privk[0]));

This will never be same as rsa_privk[0].

Because, createHexString() only uses the last 2 bytes from each array element.

Example:

rsa_privk[0] : [123676133, 198914513, 129998601, 245147334, 11918451, 206998232, 96766191, 75984899, 177840095, 106709334, 10180427, 208237547, 119814814, 127003446, 189062377, 84099480, 220452154, 250519075, 267883908, 115471915, 165124106, 238628722, 169382478, 42320122, 95982405, 80725759, 89608310, 85166267, 200925925, 254033325, 86971506, 191278317, 127411298, 180195794, 142776693, 188738169, 39016]

createHexString(rsa_privk[0]) : e5d109c673d8ef03df564beb9e36e9983a23842b0a724efa45ff76bbe5ad72ed62d2757968

parseHexString(createHexString(rsa_privk[0])) : [229, 209, 9, 198, 115, 216, 239, 3, 223, 86, 75, 235, 158, 54, 233, 152, 58, 35, 132, 43, 10, 114, 78, 250, 69, 255, 118, 187, 229, 173, 114, 237, 98, 210, 117, 121, 104]

Update : Working Solution...

The two functions... the hex always contains 8 byte blocks, each for each element in the array...

function parseHexString(str) { 
    var result = [];
    while (str.length >= 8) { 
        result.push(parseInt(str.substring(0, 8), 16));

        str = str.substring(8, str.length);
    }

    return result;
}

function createHexString(arr) {
    var result = "";
    var z;

    for (var i = 0; i < arr.length; i++) {
        var str = arr[i].toString(16);

        z = 8 - str.length + 1;
        str = Array(z).join("0") + str;

        result += str;
    }

    return result;
}

Test code...

function test() {   
    a = [123676133, 198914513, 129998601, 245147334, 11918451, 206998232, 96766191, 75984899, 177840095, 106709334, 10180427, 208237547, 119814814, 127003446, 189062377, 84099480, 220452154, 250519075, 267883908, 115471915, 165124106, 238628722, 169382478, 42320122, 95982405, 80725759, 89608310, 85166267, 200925925, 254033325, 86971506, 191278317, 127411298, 180195794, 142776693, 188738169, 39016];

    console.log("Input");
    console.log(a);

    b = createHexString(a);

    console.log("Hex");
    console.log(b);

    c = parseHexString(b); 

    console.log("Output");
    console.log(c);

    if(checkIfEqual(a, c)) {
        alert("Same");
    }
}

function checkIfEqual(arr1, arr2) {
    if (arr1.length != arr2.length) {
        return false;
    }
    //sort them first, then join them and just compare the strings
    return arr1.sort().join() == arr2.sort().join();
}

Solution 2

Convert a hex string to a byte array and vice versa

note: implementation from crypto-js

// Convert a hex string to a byte array
function hexToBytes(hex) {
    for (var bytes = [], c = 0; c < hex.length; c += 2)
        bytes.push(parseInt(hex.substr(c, 2), 16));
    return bytes;
}

// Convert a byte array to a hex string
function bytesToHex(bytes) {
    for (var hex = [], i = 0; i < bytes.length; i++) {
        var current = bytes[i] < 0 ? bytes[i] + 256 : bytes[i];
        hex.push((current >>> 4).toString(16));
        hex.push((current & 0xF).toString(16));
    }
    return hex.join("");
}

Solution 3

I just wanted to chime in that there is a library at https://github.com/dcodeIO/bytebuffer.js to easily help with conversions like this, and thus you don't need to write your own functions (which could possibly not be the most optimal, or be more optimal if your solution was reviewed through the open source community on GitHub).

var ByteBuffer = require("bytebuffer");

var bb = ByteBuffer.fromHex(yourHexString);

// need to convert it to base 64?
// bb.toBase64();

See https://github.com/dcodeIO/bytebuffer.js/wiki/API#bytebufferfromhexstr-littleendian-noassert for the API documention and more insight on the methods I used above.

Solution 4

Just to clarify, if you simply want to hex decode a simple string such as 48656C6C6F20576F726C6421 (Hello World!) you can use the OP function but instead of using a length of 8 you should use a length of 2.

Code:

var DecodeHexStringToByteArray = function (hexString) {
   var result = [];
   while (hexString.length >= 2) { 
       result.push(parseInt(hexString.substring(0, 2), 16));
       hexString = hexString.substring(2, hexString.length);
   }
   return result;
}

Output will be [72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33]

I know that this code is already in the OP question, but it's not in the accepted answer. My intent here is only to give a straight answer to the first part of the question being asked (How to convert a hex string into a bytes array).

Solution 5

I found solution over here enter link description here

function hexStringToByteArray(hexString) {
    if (hexString.length % 2 !== 0) {
        throw "Must have an even number of hex digits to convert to bytes";
    }
    var numBytes = hexString.length / 2;
    var byteArray = new Uint8Array(numBytes);
    for (var i=0; i<numBytes; i++) {
        byteArray[i] = parseInt(hexString.substr(i*2, 2), 16);
    }
    return byteArray;
}

once again thank you http://www.java2s.com

View more solutions

79,060

Author by

SkyN

Updated on November 16, 2021

Comments

SkyN over 2 years

The following code procedure bytes = parseHexString (createHexString (bytes)) leads to updated of bytes, what I would like to avoid. And as a result calculations are not correct.

<html>
<head>
<SCRIPT SRC="http://eu.static.mega.co.nz/sjcl_1.js"></SCRIPT>
<SCRIPT SRC="http://eu.static.mega.co.nz/crypto_1.js"></SCRIPT>
<SCRIPT SRC="http://eu.static.mega.co.nz/rsa_1.js"></SCRIPT>
<SCRIPT SRC="http://eu.static.mega.co.nz/hex_1.js"></SCRIPT>
<SCRIPT>
function parseHexString(str) { 
    var result = [];
    while (str.length >= 2) { 
        result.push(parseInt(str.substring(0, 2), 16));
        str = str.substring(2, str.length);
    }

    return result;
}

function createHexString(arr) {
    var result = "";
    for (i in arr) {
        var str = arr[i].toString(16);
        str = str.length == 0 ? "00" :
              str.length == 1 ? "0" + str : 
              str.length == 2 ? str :
              str.substring(str.length-2, str.length);
        result += str;
    }
    return result;
}

function t()
{
    var json_k     = 'aOrP5yLtNQT53WMQfufSlA';
    var json_csid  = 'CABD6JUMldvI_eqP0537xl9P8x7kgk2OjOq99Fy7kosphj6AFUtlbwRRDpg4EIifXRLO6FNpdD22WwtUlJ_1Mgye2Y87trEqLCbhahuEFJVQNMDtNbIem7xY2ER9uF-cdgBXZWuzp7XIBybSh7W8MSUlv_eGS6LcLGJ81Q49dSzVhcswHTJ_IJl04p3c0axR6ZIJ8dH5bJ_vXvgQsypUVVtdfMacKhB9cXdEtRZ6iWLKCKqscXdo6CNXlbIdzRhro0gxfmhfB_miysFAiSQrbtuYnIgYBU3i9p3jRlPD4ti3CUcnj0SomV61w1aEYNvo56HPMUZlVkVHA7BFzvHGHo0J';
    var json_privk = 'K7LDtk2M2QhjJx_v_Hqf0LKUBaZx76U_vBDjQty9HpFDy2MntF5HxxuyHQ9-1HmXeYzbL1pZnAxsZ7LRUbDnkR6qtJVaGdWuQhrytkuq0l5zBp-O--gZxoQPRGTsVgVRdAvpsRTkQI_q8fxADLCe0womFxtvvnD_FJgjaMsm7vkYchXkoq33WWyHijb3JMkymjl0_GtiSamT0qEL6sm_l5Z1lehqBGUEHfYAa0ub8IDx_yqy2R9Nh8Lwzmz4s24sShVxjaNsMBlSE-sEvTziOsnNWK1Zl_XUYadlENkweuIoxYx_lt8XIV71TzjEFuVTd-pXhzVlqePmIu3SM3bO1Kzq_DnGfB62RmzlmbtHU4iyw4Hd1wQFRhTeSRrvMjsMPFKN-SIIQU7CRNaMuaDxZbNZcOKhMg_h9mApM0rRS3VZaGZzFTL9rSaDMYHw4pL3aOkSFPMY3w785Tss7Zqwuo9HFUWUVbnYAb97JkgCohlMotORrMMtual1dQ4sG1sIYXyWTckAGGL0ZAGurhtSKiyz1m8Lb39pXPacqFh_nCHqqb2_RdrKTj0PdGZESKkU8YedeqC1I9nR4v38DuQc-pBBR5DOwgNjJMvzvsUehs_PxIL8THjgIcr7ONc4hWV9o2v_l81Vo2cCW2I99Iz84IFN2fV1dTqHIG_tnLzz8ljBVygETUqrFdZ0JlQJkurZ7RBku5krm-k9CZmDezCIzPPil-RcYzVIk00gNYAxfiZE48Or4WEiGjgKLnHCYVtSlvlMF4bPGB4SVCZ-68j49EjfSWaMK0OoMkpGhqf7KchgxYBZq6o3AhLgp4t0BClvsdee6VTz1SFqc3m2A-TMG6fNdbCT_Q9nYCYdZIROdOc';

    var aes = new sjcl.cipher.aes( prepare_key_pw("oEyoo9cQcw") );
    k = decrypt_key(aes, base64_to_a32(json_k) );

    aes = new sjcl.cipher.aes(k);

    var t = mpi2b(base64urldecode(json_csid));

    var privk = a32_to_str(decrypt_key(aes,base64_to_a32(json_privk)));

    var rsa_privk = Array(4);
    for (var i = 0; i < 4; i++)
    {
        var l = ((privk.charCodeAt(0)*256+privk.charCodeAt(1)+7)>>3)+2;

        rsa_privk[i] = mpi2b(privk.substr(0,l));
        if (typeof rsa_privk[i] == 'number') break;
        privk = privk.substr(l);    
    }

    var p = parseHexString(createHexString(rsa_privk[0]));  // !!!!!!!!!!!!!!!!!!!!!!!!!!!!
    var q = parseHexString(createHexString(rsa_privk[1]));  // !!!!!!!!!!!!!!!!!!!!!!!!!!!!
    var d = parseHexString(createHexString(rsa_privk[2]));  // !!!!!!!!!!!!!!!!!!!!!!!!!!!!
    var u = parseHexString(createHexString(rsa_privk[3]));  // !!!!!!!!!!!!!!!!!!!!!!!!!!!!
    sid = base64urlencode(b2s(RSAdecrypt(t,d,p,q,u)).substr(0,43));
    if (sid!=='tajetAbW0qTQGFlwp8iD5lQ0TFV1QUZJZFVvjRX7Xx-bPzYBoau7qog09w')
        console.log("ERROR");

    p = rsa_privk[0];
    q = rsa_privk[1];
    d = rsa_privk[2];
    u = rsa_privk[3];
    sid = base64urlencode(b2s(RSAdecrypt(t,d,p,q,u)).substr(0,43));
    if (sid=='tajetAbW0qTQGFlwp8iD5lQ0TFV1QUZJZFVvjRX7Xx-bPzYBoau7qog09w')
        console.log("OK");
}
</script>

</head>
<body onload="t();"></body>
</html>

I am not javascript developer, and not one found in google code did not work on this data.

Update 1

console.log(createHexString(rsa_privk[0])); = e5d109c673d8ef03df564beb9e36e9983a23842b0a724efa45ff76bbe5ad72ed62d2757968

But if do

parseHexString('e5d109c673d8ef03df564beb9e36e9983a23842b0a724efa45ff76bbe5ad72ed‌62d2757968');

then code if (sid!== ... make error

Update 2

console.log(rsa_privk[0].toString(16));

output: 123676133,198914513,129998601,245147334,11918451,206998232,96766191,75984899,177840095,106709334,10180427,208237547,119814814,127003446,189062377,84099480,220452154,250519075,267883908,115471915,165124106,238628722,169382478,42320122,95982405,80725759,89608310,85166267,200925925,254033325,86971506,191278317,127411298,180195794,142776693,188738169,39016

Update 3

console.log(parseHexString(createHexString(rsa_privk[0])));
console.log(rsa_privk[0]);

output:

[229, 209, 9, 198, 115, 216, 239, 3, 223, 86, 75, 235, 158, 54, 233, 152, 58, 35, 132, 43, 10, 114, 78, 250, 69, 255, 118, 187, 229, 173, 114, 237, 98, 210, 117, 121, 104]

[123676133, 198914513, 129998601, 245147334, 11918451, 206998232, 96766191, 75984899, 177840095, 106709334, 10180427, 208237547, 119814814, 127003446, 189062377, 84099480, 220452154, 250519075, 267883908, 115471915, 165124106, 238628722, 169382478, 42320122, 95982405, 80725759, 89608310, 85166267, 200925925, 254033325, 86971506, 191278317, 127411298, 180195794, 142776693, 188738169, 39016]