Cng.cs

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using System;
using System.Runtime.InteropServices;
using Internal.Cryptography;
using Microsoft.Win32.SafeHandles;
 
namespace Internal.NativeCrypto;
 
internal static class Cng
{
    [Flags]
    public enum OpenAlgorithmProviderFlags
    {
        NONE = 0,
        BCRYPT_ALG_HANDLE_HMAC_FLAG = 8
    }
 
    internal static class Interop
    {
        [DllImport("BCrypt.dll", CharSet = CharSet.Unicode)]
        public static extern global::Interop.BCrypt.NTSTATUS BCryptOpenAlgorithmProvider(out Internal.NativeCrypto.SafeAlgorithmHandle phAlgorithm, string pszAlgId, string pszImplementation, int dwFlags);
 
        [DllImport("BCrypt.dll", CharSet = CharSet.Unicode)]
        public static extern global::Interop.BCrypt.NTSTATUS BCryptSetProperty(Internal.NativeCrypto.SafeAlgorithmHandle hObject, string pszProperty, string pbInput, int cbInput, int dwFlags);
 
        [DllImport("BCrypt.dll", CharSet = CharSet.Unicode, EntryPoint = "BCryptSetProperty")]
        private static extern global::Interop.BCrypt.NTSTATUS BCryptSetIntPropertyPrivate(Microsoft.Win32.SafeHandles.SafeBCryptHandle hObject, string pszProperty, ref int pdwInput, int cbInput, int dwFlags);
 
        public static global::Interop.BCrypt.NTSTATUS BCryptSetIntProperty(Microsoft.Win32.SafeHandles.SafeBCryptHandle hObject, string pszProperty, ref int pdwInput, int dwFlags)
        {
            return BCryptSetIntPropertyPrivate(hObject, pszProperty, ref pdwInput, 4, dwFlags);
        }
    }
 
    public static Internal.NativeCrypto.SafeAlgorithmHandle BCryptOpenAlgorithmProvider(string pszAlgId, string pszImplementation, OpenAlgorithmProviderFlags dwFlags)
    {
        Internal.NativeCrypto.SafeAlgorithmHandle phAlgorithm;
        global::Interop.BCrypt.NTSTATUS nTSTATUS = Interop.BCryptOpenAlgorithmProvider(out phAlgorithm, pszAlgId, pszImplementation, (int)dwFlags);
        if (nTSTATUS != 0)
        {
            throw CreateCryptographicException(nTSTATUS);
        }
        return phAlgorithm;
    }
 
    public static void SetFeedbackSize(this Internal.NativeCrypto.SafeAlgorithmHandle hAlg, int dwFeedbackSize)
    {
        global::Interop.BCrypt.NTSTATUS nTSTATUS = Interop.BCryptSetIntProperty(hAlg, "MessageBlockLength", ref dwFeedbackSize, 0);
        if (nTSTATUS != 0)
        {
            throw CreateCryptographicException(nTSTATUS);
        }
    }
 
    public static void SetCipherMode(this Internal.NativeCrypto.SafeAlgorithmHandle hAlg, string cipherMode)
    {
        global::Interop.BCrypt.NTSTATUS nTSTATUS = Interop.BCryptSetProperty(hAlg, "ChainingMode", cipherMode, (cipherMode.Length + 1) * 2, 0);
        if (nTSTATUS != 0)
        {
            throw CreateCryptographicException(nTSTATUS);
        }
    }
 
    private static Exception CreateCryptographicException(global::Interop.BCrypt.NTSTATUS ntStatus)
    {
        int hr = (int)(ntStatus | (global::Interop.BCrypt.NTSTATUS)16777216u);
        return hr.ToCryptographicException();
    }
}