How to convert this sequence to this hash?

Question

Hi there,

I'm consuming a webservice from my application in C# .net (2.0) that return values (as string) like this:

%23k.%0d%16%c4%8a%18%efG%28%b9c%12%b7%f1%e2%e7j%93

I know that the real value for that is:

236B2E0D16C48A18EF4728B96312B7F1E2E76A93

But I don't know how to convert from the returned value to the real value.

Any thoughts?

Anyway, thanks for your time. Cheers.

Answer 1

I'm not certain of this, but try using the System.Web.HttpUtility.UrlDecode method

Answer 2

Going down the line:

If you encounter '%' copy the next two characters

Otherwise take the ascii code of the character found and output as hex

%23  => 23
k    => 6B
.    => 2E
%0d  => 0D

ASCII Table

But in code I'm pretty sure this will work:

char c = 'k';
int ascii = (int)c;
string hex = ascii.ToString("X2");

Answer 3

Thanks for the info Rob. If anyone wants the full method here it is:

static private string convertInfoHash(string encodedHash)
{
    string convertedHash = string.Empty;
    for (int i = 0; i < encodedHash.Length; i++)
    {
        if (encodedHash[i] == '%')
        {
            convertedHash += String.Format("{0}{1}",encodedHash[i + 1],encodedHash[i + 2]);
            i += 2;
        }
        else
        {
            int ascii = (int)encodedHash[i];
            convertedHash += ascii.ToString("X2");

        }
    }

    return convertedHash;
}