C# SHA256 ComputeHash result different with CryptoJS SHA256 function

Question

I have a C# function as below:

string stringvalue = "530500480530490480530480480520570480520510500490";
var encodedvalue= Encoding.Unicode.GetBytes(stringvalue);
using (HashAlgorithm ssp = System.Security.Cryptography.HashAlgorithm.Create("SHA256"))
        {

            var digest = ssp.ComputeHash(encodedvalue);

            return BitConverter.ToString(digest); 

        }

I need to create a javascript function that match the code above so that the end result for both C# and JS is the same.

Currently in my JS code, I'm using this:

var hash = CryptoJS.SHA256("530500480530490480530480480520570480520510500490");
var hexhash = hash.toString(CryptoJS.enc.hex);

This is the result of my hexhash:

d956678c8f12c65299daf35019a9a1eb3e6eb9855fd850aeb5aafe46057d179e

But in my C# code, this line of var digest = ssp.ComputeHash(bPass); return the following array:

I don't know much about encoding. Please tell me what type of result is being populated in the c# code above? If I'm not mistaken, the ComputeHash is returning bytes but I need lots of reading to confirm that which is another long hour of studying

I tried many different ways of converting the JS Sha256 code but no luck. I'm stuck at this particular line for almost a day.

Please help. Thanks

EDIT: Sorry for the code error. I had updated the C# code. ComputeHash accept an array

Answer 1

In my example I am using System.Security.Cryptography.SHA256Managed to get SHA256 in C#.

The method SHA256Managed.ComputeHash takes a byte array as a parameter and return another byte array. Now we need to convert back your byte array to a string.

The following code return the same result a Javascript SHA-256.

 byte[] bytes = Encoding.UTF8.GetBytes("530500480530490480530480480520570480520510500490");
 SHA256Managed hashstring = new SHA256Managed();
 byte[] hash = hashstring.ComputeHash(bytes);
 string hashString = string.Empty;
 foreach (byte x in hash)
 {
     hashString += String.Format("{0:x2}", x);
 }
 return(hashString);

Just to explain : String.Format("{0:x2}", x)

• X means Hexadecimal format.
• 2 means 2 characters.

Answer 2

I finally found the answer after uncountable hours of trial and error.

The C# code var digest = ssp.ComputeHash(encodedvalue) is returning byte array from the result of var encodedvalue= Encoding.Unicode.GetBytes(stringvalue); as Jean replied. In order to create the function in Javascript, I need to ensure that the encodedvalue is producing the correct encoding format and size just like the one in C#.

Using only CryptoJS, I manage to get the matching result from below

function GetHexFromString() {
var stringVal = '8563A578-7402-4567-A6CE-4DE4E0825B021234';
// Convert the string to UTF 16 little-endian
// Result: 560530540510650530550560450550520480500450520530540550450650540670690450520680690520690480560500530660480500490500510520
var utf16le = CryptoJS.enc.Utf16LE.parse(stringVal);  

// Convert to Sha256 format and get the word array
var utf16Sha256 = CryptoJS.SHA256(utf16le);
// Convert the Sha256 word array to Uint8Array to get the 32 byte array just to see the result to ensure it match with the C# function
// Result: 94,203,69,29,35,202,209,149,121,144,44,6,98,250,141,161,102,7,238,35,228,117,111,236,118,115,51,113,134,72,52,69
var utf16sha256Array = convertWordArrayToUint8Array(utf16Sha256); 

// Convert the Sha256 to hex (if i'm not mistaken, it's base 16) format
var hexSha256 = utf16Sha256.toString(CryptoJS.enc.hex);

 // Insert a dash in between 2 characters in the string
 hexSha256 = hexSha256.replace(/(\S{2})/g, "$1-");
 // Remove the last dash in the string
 hexSha256 = hexSha256.replace(/-$/, "");

// Final Result: 5E-CB-45-1D-23-CA-D1-95-79-90-2C-06-62-FA-8D-A1-66-07-EE-23-E4-75-6F-EC-76-73-33-71-86-48-34-45
return hexSha256.toUpperCase();
}

function convertWordArrayToUint8Array(wordArray) {
        var len = wordArray.words.length,
            u8_array = new Uint8Array(len << 2),
            offset = 0, word, i
        ;
        for (i = 0; i < len; i++) {
            var word = wordArray.words[i];                

            u8_array[offset++] = word >> 24;
            u8_array[offset++] = (word >> 16) & 0xff;
            u8_array[offset++] = (word >> 8) & 0xff;
            u8_array[offset++] = word & 0xff;                                              
        }
        return u8_array;
    }

Hope it help whoever that need such method

Answer 3

An alternative to Koo SengSeng's answer (if you don't want to use CryptoJS library).
SHA256 function is from here, the arrToUintArr function is from Koo SengSeng's answer.

var SHA256=function a(b){function c(a,b){return a>>>b|a<<32-b}for(var d,e,f=Math.pow,g=f(2,32),h="length",i="",j=[],k=8*b[h],l=a.h=a.h||[],m=a.k=a.k||[],n=m[h],o={},p=2;64>n;p++)if(!o[p]){for(d=0;313>d;d+=p)o[d]=p;l[n]=f(p,.5)*g|0,m[n++]=f(p,1/3)*g|0}for(b+="\x80";b[h]%64-56;)b+="\x00";for(d=0;d<b[h];d++){if(e=b.charCodeAt(d),e>>8)return;j[d>>2]|=e<<(3-d)%4*8}for(j[j[h]]=k/g|0,j[j[h]]=k,e=0;e<j[h];){var q=j.slice(e,e+=16),r=l;for(l=l.slice(0,8),d=0;64>d;d++){var s=q[d-15],t=q[d-2],u=l[0],v=l[4],w=l[7]+(c(v,6)^c(v,11)^c(v,25))+(v&l[5]^~v&l[6])+m[d]+(q[d]=16>d?q[d]:q[d-16]+(c(s,7)^c(s,18)^s>>>3)+q[d-7]+(c(t,17)^c(t,19)^t>>>10)|0),x=(c(u,2)^c(u,13)^c(u,22))+(u&l[1]^u&l[2]^l[1]&l[2]);l=[w+x|0].concat(l),l[4]=l[4]+w|0}for(d=0;8>d;d++)l[d]=l[d]+r[d]|0}for(d=0;8>d;d++)for(e=3;e+1;e--){var y=l[d]>>8*e&255;i+=(16>y?0:"")+y.toString(16)}return i};
var arrToUintArr=function(a){for(var l=a.length,b=new Uint8Array(l<<2),o=0,w,i=0;i<l;i++) w=a[i],b[o++]=w>>24,b[o++]=(w>>16)&0xff,b[o++]=(w>>8)&0xff,b[o++]=w&0xff;return b;}
var computeHash=function(k){for(var a=[],s=SHA256(k),i=0;i<8;i++) a.push(parseInt(s.substr(i*8,8),16));return arrToUintArr(a);}

computeHash(k) will return an array of numbers representing bytes.

This is equal to below code in C#:

new System.Security.Cryptography.SHA256CryptoServiceProvider().ComputeHash(Encoding.UTF8.GetBytes(k));

Answer 4

Try

var digest = ssp.ComputeHash(Encoding.UTF8.GetBytes(stringvalue))

return BitConverter.ToString(digest)
                   .Replace("-", string.Empty)
                   .ToLowerInvariant();

That js library is converting the string to UTF8 before calculating its hash.

Answer 5

typescript code:

private computeHash(text: string): string {
    return CryptoJS.SHA256(text).toString();
}

c# equivalent:

private string ComputeHash(string text)
{
    using (var sha256 = SHA256.Create())
    {
       var bytes = Encoding.UTF8.GetBytes(text);
       var hash = sha256.ComputeHash(bytes);
       return hash.Aggregate(string.Empty, (current, x) => current + $"{x:x2}");
    }
}

Answer 6

after two days of research it works perfectly! Two different codes give the same result.

js

const sha1 = require('sha1');    
const getHash = str =>{
    const hashingBytes = Buffer.from(sha1(str), "hex");
    const base64Value = Buffer.from(hashingBytes).toString('base64');
    return base64Value;
}

c#

 System.Security.Cryptography.SHA1 sha = new System.Security.Cryptography.SHA1CryptoServiceProvider();
        byte[] bytes = System.Text.Encoding.ASCII.GetBytes(str);
        byte[] hashingbytes = sha.ComputeHash(bytes);
        var hash = Convert.ToBase64String(hashingbytes);