AesImplementation.cs

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using System;
using System.Security.Cryptography;
using Internal.NativeCrypto;
 
namespace Internal.Cryptography;
 
internal sealed class AesImplementation : Aes
{
    public sealed override ICryptoTransform CreateDecryptor()
    {
        return CreateTransform(Key, IV, encrypting: false);
    }
 
    public sealed override ICryptoTransform CreateDecryptor(byte[] rgbKey, byte[] rgbIV)
    {
        return CreateTransform(rgbKey, rgbIV.CloneByteArray(), encrypting: false);
    }
 
    public sealed override ICryptoTransform CreateEncryptor()
    {
        return CreateTransform(Key, IV, encrypting: true);
    }
 
    public sealed override ICryptoTransform CreateEncryptor(byte[] rgbKey, byte[] rgbIV)
    {
        return CreateTransform(rgbKey, rgbIV.CloneByteArray(), encrypting: true);
    }
 
    public sealed override void GenerateIV()
    {
        IV = RandomNumberGenerator.GetBytes(BlockSize / 8);
    }
 
    public sealed override void GenerateKey()
    {
        Key = RandomNumberGenerator.GetBytes(KeySize / 8);
    }
 
    protected sealed override void Dispose(bool disposing)
    {
        base.Dispose(disposing);
    }
 
    protected override bool TryDecryptEcbCore(ReadOnlySpan<byte> ciphertext, Span<byte> destination, PaddingMode paddingMode, out int bytesWritten)
    {
        UniversalCryptoTransform universalCryptoTransform = CreateTransformCore(CipherMode.ECB, paddingMode, Key, null, BlockSize / 8, BlockSize / 8, 0, encrypting: false);
        using (universalCryptoTransform)
        {
            return universalCryptoTransform.TransformOneShot(ciphertext, destination, out bytesWritten);
        }
    }
 
    protected override bool TryEncryptEcbCore(ReadOnlySpan<byte> plaintext, Span<byte> destination, PaddingMode paddingMode, out int bytesWritten)
    {
        UniversalCryptoTransform universalCryptoTransform = CreateTransformCore(CipherMode.ECB, paddingMode, Key, null, BlockSize / 8, BlockSize / 8, 0, encrypting: true);
        using (universalCryptoTransform)
        {
            return universalCryptoTransform.TransformOneShot(plaintext, destination, out bytesWritten);
        }
    }
 
    protected override bool TryEncryptCbcCore(ReadOnlySpan<byte> plaintext, ReadOnlySpan<byte> iv, Span<byte> destination, PaddingMode paddingMode, out int bytesWritten)
    {
        UniversalCryptoTransform universalCryptoTransform = CreateTransformCore(CipherMode.CBC, paddingMode, Key, iv.ToArray(), BlockSize / 8, BlockSize / 8, 0, encrypting: true);
        using (universalCryptoTransform)
        {
            return universalCryptoTransform.TransformOneShot(plaintext, destination, out bytesWritten);
        }
    }
 
    protected override bool TryDecryptCbcCore(ReadOnlySpan<byte> ciphertext, ReadOnlySpan<byte> iv, Span<byte> destination, PaddingMode paddingMode, out int bytesWritten)
    {
        UniversalCryptoTransform universalCryptoTransform = CreateTransformCore(CipherMode.CBC, paddingMode, Key, iv.ToArray(), BlockSize / 8, BlockSize / 8, 0, encrypting: false);
        using (universalCryptoTransform)
        {
            return universalCryptoTransform.TransformOneShot(ciphertext, destination, out bytesWritten);
        }
    }
 
    protected override bool TryDecryptCfbCore(ReadOnlySpan<byte> ciphertext, ReadOnlySpan<byte> iv, Span<byte> destination, PaddingMode paddingMode, int feedbackSizeInBits, out int bytesWritten)
    {
        ValidateCFBFeedbackSize(feedbackSizeInBits);
        UniversalCryptoTransform universalCryptoTransform = CreateTransformCore(CipherMode.CFB, paddingMode, Key, iv.ToArray(), BlockSize / 8, feedbackSizeInBits / 8, feedbackSizeInBits / 8, encrypting: false);
        using (universalCryptoTransform)
        {
            return universalCryptoTransform.TransformOneShot(ciphertext, destination, out bytesWritten);
        }
    }
 
    protected override bool TryEncryptCfbCore(ReadOnlySpan<byte> plaintext, ReadOnlySpan<byte> iv, Span<byte> destination, PaddingMode paddingMode, int feedbackSizeInBits, out int bytesWritten)
    {
        ValidateCFBFeedbackSize(feedbackSizeInBits);
        UniversalCryptoTransform universalCryptoTransform = CreateTransformCore(CipherMode.CFB, paddingMode, Key, iv.ToArray(), BlockSize / 8, feedbackSizeInBits / 8, feedbackSizeInBits / 8, encrypting: true);
        using (universalCryptoTransform)
        {
            return universalCryptoTransform.TransformOneShot(plaintext, destination, out bytesWritten);
        }
    }
 
    private ICryptoTransform CreateTransform(byte[] rgbKey, byte[] rgbIV, bool encrypting)
    {
        if (rgbKey == null)
        {
            throw new ArgumentNullException("rgbKey");
        }
        long num = (long)rgbKey.Length * 8L;
        if (num > int.MaxValue || !((int)num).IsLegalSize(LegalKeySizes))
        {
            throw new ArgumentException(System.SR.Cryptography_InvalidKeySize, "rgbKey");
        }
        if (rgbIV != null)
        {
            long num2 = (long)rgbIV.Length * 8L;
            if (num2 != BlockSize)
            {
                throw new ArgumentException(System.SR.Cryptography_InvalidIVSize, "rgbIV");
            }
        }
        if (Mode == CipherMode.CFB)
        {
            ValidateCFBFeedbackSize(FeedbackSize);
        }
        return CreateTransformCore(Mode, Padding, rgbKey, rgbIV, BlockSize / 8, this.GetPaddingSize(Mode, FeedbackSize), FeedbackSize / 8, encrypting);
    }
 
    private static void ValidateCFBFeedbackSize(int feedback)
    {
        if (feedback != 8 && feedback != 128)
        {
            throw new CryptographicException(string.Format(System.SR.Cryptography_CipherModeFeedbackNotSupported, feedback, CipherMode.CFB));
        }
    }
 
    private static UniversalCryptoTransform CreateTransformCore(CipherMode cipherMode, PaddingMode paddingMode, byte[] key, byte[] iv, int blockSize, int paddingSize, int feedbackSize, bool encrypting)
    {
        SafeAlgorithmHandle sharedHandle = AesBCryptModes.GetSharedHandle(cipherMode, feedbackSize);
        BasicSymmetricCipher cipher = new BasicSymmetricCipherBCrypt(sharedHandle, cipherMode, blockSize, paddingSize, key, ownsParentHandle: false, iv, encrypting);
        return UniversalCryptoTransform.Create(paddingMode, cipher, encrypting);
    }
}