HashAlgorithm.Create fails with PlatformNotSupportedException in C# ASP.NET Core 2

Question

I have an ASP.Net MVC project which works fine when using HashAlgorithm, but I am trying to replicate this same project in ASP.NET Core 2 and I am getting the following error:

System.PlatformNotSupportedException HResult=0x80131539 Message=Operation is not supported on this platform. Source=System.Security.Cryptography.Primitives StackTrace: at System.Security.Cryptography.HashAlgorithm.Create(String hashName) at Hash.Program.EncodePassword(String pass, String salt)

My code:

public static string GeneratePassword(int saltlength) //length of salt
{
    const string chars = "abcdefghijkmnopqrstuvwxyzABCDEFGHJKLMNOPQRSTUVWXYZ0123456789";
    var randNum = new Random();
    var passwordSalt = new char[saltlength];

    for (var i = 0; i <= saltlength - 1; i++) {
        passwordSalt[i] = chars[Convert.ToInt32((chars.Length) * randNum.NextDouble())];
    }
    return new string(passwordSalt);
}
public static string EncodePassword(string pass, string salt) //encrypt password
{
    byte[] bytes = Encoding.Unicode.GetBytes(pass);
    byte[] src = Encoding.Unicode.GetBytes(salt);
    byte[] dst = new byte[src.Length + bytes.Length];
    Buffer.BlockCopy(src, 0, dst, 0, src.Length);
    Buffer.BlockCopy(bytes, 0, dst, src.Length, bytes.Length);
    HashAlgorithm algorithm = HashAlgorithm.Create("MD5");
    if (algorithm != null) {
        byte[] inArray = algorithm.ComputeHash(dst);
        var encodedPassword = Convert.ToBase64String(inArray);
        return encodedPassword;
    }
    return pass;
}

Any suggestion on how to fix this error?

Answer 1

There is a github issue for this problem which provides a workaround:

Workaround is to call (HashAlgorithm)CryptoConfig.CreateFromName(string), though calling CryptoConfig directly is generally discouraged.

Answer 2

To create an MD5 hash object, use MD5.Create(). The only reason to use CryptoConfig or HashAlgorithm.Create(String) is when handling dynamic needs.