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How to convert hex string into a bytes array, and a bytes array in the hex string?
Asked Answered
Solved javascriptarraysstringhex
O

7

38

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('e5d109c673d8ef03df564beb9e36e9983a23842b0a724efa45ff76bbe5ad72ed‌​62d2757968');

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]
Outpour answered 30/1, 2013 at 11:43 Comment(7)
What data are you expecting and what data are you getting? – Waldemar
I expect that the transformation data = parseHexString (createHexString (data)) not change the data – Outpour
Copy paste your input to createHexString(rsa_privk[0]), ie console.log(rsa_privk[0]);. – Waldemar
console.log(createHexString(rsa_privk[0])); = e5d109c673d8ef03df564beb9e36e9983a23842b0a724efa45ff76bbe5ad72ed62d2757968 But if do parseHexString('e5d109c673d8ef03df564beb9e36e9983a23842b0a724efa45ff76bbe5ad72ed62d2757968'); then code if (sid!== ... make error – Outpour
See my updated answer, just add the console.log line and copy paste the whole output in your question. – Waldemar
OK, so if I understand correctly, you want to just display the data as hex, right? Why do you need to convert it back? – Waldemar
Updated answer with solution... enjoy... – Waldemar
W
14

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();
}
Waldemar answered 30/1, 2013 at 11:46 Comment(10)
What is your input and output? – Waldemar
The data is in binary form in the code above. The question is how to display them in hex ​​format. But I'm sure not getting the correct result, because with inverse transformation data is not correctly. – Outpour
What is your data like? Copy paste the data here. – Waldemar
data is binary, I can not insert here the binary data!!! they are calculated in the above code. And I do not know how to properly convert them to hex and back to binary – Outpour
arr[i] gives back a character. what you want is the byte number from the character which you can get with .charCodeAt( ... ) – Particia
What is your algorithm like? The current createHexString takes the last 2 bytes of the data given as input. Like for your example input, 123676133, the function only takes 33. Is this what you need in your algorithm? – Waldemar
@Outpour Please run this console.log(rsa_privk[0]); and paste output. – Waldemar
Creates ugly global variable z. – Oriente
@PointerNull Just replace instance of z with its value. – Waldemar
Sure, I'm just pointing that your example code pollutes global namespace. You're missing one "var". – Oriente
V
84

Convert a hex string to a byte array and vice versa

note: implementation from crypto-js, though now out of date and slightly altered

// Convert a hex string to a byte array
function hexToBytes(hex) {
    let bytes = [];
    for (let 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) {
    let hex = [];
    for (let i = 0; i < bytes.length; i++) {
        let current = bytes[i] < 0 ? bytes[i] + 256 : bytes[i];
        hex.push((current >>> 4).toString(16));
        hex.push((current & 0xF).toString(16));
    }
    return hex.join("");
}
Vachill answered 18/12, 2015 at 13:2 Comment(8)
THIS works. Nothing else worked for me. Thank you SO much. – Soapbox
Just a reminder, crypto-js api has changed to CryptoJS.enc.Hex.parse(), there is no hexToBytes – Shandrashandrydan
The code has changed a little from the original. Here is the link to the latest bytesToHex (stringify) and hexToBytes (parse) methods: crypto-js/core.js#L390 – Windswept
bytesToHex calculates strange on some circumtances. e.g. [159,15] is been calculated as '9f0f' it should be '9ff'. [25,255] does work again. Is this an endianess thing? The issues are beginning with 9th bit of the first array element. Function createHexString from the accepted answer works for me. – Grossularite
@Grossularite I cannot reproduce your issue. the code works good to me – Parrett
Whats wrong with just using Buffer.toString("hex") and Buffer.from(str, "hex")? – Mestee
substr seems to be deprecated, but substr(c, 2) can be easily replaced by substring(c, c + 2) – Fluoride
@Mestee That only works in Node. – Mcgregor
W
14

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();
}
Waldemar answered 30/1, 2013 at 11:46 Comment(10)
What is your input and output? – Waldemar
The data is in binary form in the code above. The question is how to display them in hex ​​format. But I'm sure not getting the correct result, because with inverse transformation data is not correctly. – Outpour
What is your data like? Copy paste the data here. – Waldemar
data is binary, I can not insert here the binary data!!! they are calculated in the above code. And I do not know how to properly convert them to hex and back to binary – Outpour
arr[i] gives back a character. what you want is the byte number from the character which you can get with .charCodeAt( ... ) – Particia
What is your algorithm like? The current createHexString takes the last 2 bytes of the data given as input. Like for your example input, 123676133, the function only takes 33. Is this what you need in your algorithm? – Waldemar
@Outpour Please run this console.log(rsa_privk[0]); and paste output. – Waldemar
Creates ugly global variable z. – Oriente
@PointerNull Just replace instance of z with its value. – Waldemar
Sure, I'm just pointing that your example code pollutes global namespace. You're missing one "var". – Oriente
N
9

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.

Nairobi answered 17/3, 2016 at 1:35 Comment(0)
Y
3

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).

Yurikoyursa answered 20/10, 2015 at 16:15 Comment(0)
E
3

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

Espalier answered 15/11, 2021 at 21:5 Comment(0)
S
0

Here is a live sample for this test.

http://jsfiddle.net/vincentwang2020/eks1z4g2/

function testcreateHexString()
{
    alert('test function createHexString');
    var key = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24];
    var result = createHexString(key);
    alert ('Hex value:' + result);

    alert('test function parseHexString');

    var key2 = parseHexString(result);

    if (key.sort().join() == key2.sort().join())
        alert ('Matched');

}
Scales answered 13/2, 2015 at 18:34 Comment(0)
J
0

Here's some potentially inefficient one-liners if that's your deal:

const h2b = /** @param {string} s */ s => new Uint8Array([...s.matchAll(/../g)].map(m => parseInt(m[0], 16)));
const b2h = /** @param {Uint8Array} b */ b => [...b].map(n => n.toString(16)).join("");

and some test code

import { expect, test } from "vitest";

test("h2b", () => {
    const h = "deadB33F";
    const b = new Uint8Array([0xde, 0xad, 0xb3, 0x3f]);

    expect(h2b(h), "h2b").toEqual(b);
    expect(b2h(b), "b2h").toEqual(h.toLowerCase());
});
Julissa answered 15/5 at 8:27 Comment(0)

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