MachineKeyDataProtector Implementation from StackOverflow

MachineKeyDataProtector.cs

public class MachineKeyProtectionProvider : IDataProtectionProvider
{
    public IDataProtector Create(params string[] purposes)
    {
        return new MachineKeyDataProtector(purposes);
    }
}

public class MachineKeyDataProtector : IDataProtector
{
    private readonly string[] _purposes;

    public MachineKeyDataProtector(string[] purposes)
    {
        _purposes = purposes;
    }

    public byte[] Protect(byte[] userData)
    {
        return MachineKey.Protect(userData, _purposes);
    }

    public byte[] Unprotect(byte[] protectedData)
    {
        return MachineKey.Unprotect(protectedData, _purposes);
    }
}