Myujth

I am trying to work with an api in .Net framework 4.5 that supposed to provide me cryptocurrencies wallet. in a part of it's documentations it says:

Pass Pin Code through the PBKDF2 function with 128 Bit Key Length and
1,024 iterations of SHA256

i could not find the Specify method in C# to do that. in documentations they have input "be9d3a4f1220495a96c38d36d8558365" as pin code and the out put is "4369cb0560d54f55d0c03564fbd983c4".
it seems that i should use Rfc2898DeriveBytes Method, and i used it like code below but i didnot get the same result.

string output = Convert.ToBase64String((new Rfc2898DeriveBytes("e24546d6643137a310968566cf1cd42b",16, 1024)).GetBytes(32));

output ==> 'x10zclBJY2eeZqjMyPfQm4ljyMFPvWbxF72Om2DCzHE='

It's probably best to implement your own version of PBKDF2. PBKDF2 is the actual algorithm implemented by the badly named Rfc2898DeriveBytes class.

As .NET 4.5 doesn't include the functionality to use PBKDF2 with a different hash. .NET version 4.7.2 does include the functionality but it doesn't allow the salt to be zero bytes.

So therefore it is best to implement your own version. The .NET version of Microsoft has specific copyright notices that do not seem compatible. One way to go around this is to implement PBKDF2 from Mono, but the later versions of Mono do not implement this class (it seems) and they do not implement the version where the hash can be chosen.

Fortunately bartonjs has indicated a version that has the permissive MIT license, which can be used, leading to the following solution:

using System;
using System.Security.Cryptography;
using System.Text;

namespace StackOverflow

 public class Rfc2898DeriveBytes : DeriveBytes
 

this is a class where more specific exceptions have been rewritten, some specialized cloning is replaced, and the random salt generation is generalized. The minimum salt size has also been set to 0. Otherwise it is the same code in a different name space.

It is possible to use it like this:

string pw = "be9d3a4f1220495a96c38d36d8558365";
byte salt = new byte[0];
int iterations = 1024;

Rfc2898DeriveBytes pbkdf2 = new Rfc2898DeriveBytes(pw, salt, iterations, "SHA-256");
byte key = pbkdf2.GetBytes(16);

Note that the PIN is hexadecimals encoded as UTF-8, the default encoding for PBKDF2 (not the default encoding for .NET!). The result is a key that, when represented as hexadecimals equals 4369cb0560d54f55d0c03564fbd983c4.

I've converted to a 4.5 compatible class using a string to indicate the hash function, for the one with an enum HashAlgorithm (4.6 or something similar) take a look at the revision history.