DESCryptoServiceProvider.cs

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using System.ComponentModel;
using Internal.Cryptography;
 
namespace System.Security.Cryptography;
 
[Obsolete("Derived cryptographic types are obsolete. Use the Create method on the base type instead.", DiagnosticId = "SYSLIB0021", UrlFormat = "https://aka.ms/dotnet-warnings/{0}")]
[EditorBrowsable(EditorBrowsableState.Never)]
public sealed class DESCryptoServiceProvider : DES
{
    public DESCryptoServiceProvider()
    {
        FeedbackSizeValue = 8;
    }
 
    public override void GenerateKey()
    {
        byte[] array = new byte[8];
        RandomNumberGenerator.Fill(array);
        while (DES.IsWeakKey(array) || DES.IsSemiWeakKey(array))
        {
            RandomNumberGenerator.Fill(array);
        }
        KeyValue = array;
    }
 
    public override void GenerateIV()
    {
        IVValue = RandomNumberGenerator.GetBytes(8);
    }
 
    public override ICryptoTransform CreateDecryptor()
    {
        return CreateTransform(Key, IV, encrypting: false);
    }
 
    public override ICryptoTransform CreateDecryptor(byte[] rgbKey, byte[]? rgbIV)
    {
        return CreateTransform(rgbKey, rgbIV?.CloneByteArray(), encrypting: false);
    }
 
    public override ICryptoTransform CreateEncryptor()
    {
        return CreateTransform(Key, IV, encrypting: true);
    }
 
    public override ICryptoTransform CreateEncryptor(byte[] rgbKey, byte[]? rgbIV)
    {
        return CreateTransform(rgbKey, rgbIV?.CloneByteArray(), encrypting: true);
    }
 
    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 (DES.IsWeakKey(rgbKey))
        {
            throw new CryptographicException(System.SR.Cryptography_InvalidKey_Weak, "DES");
        }
        if (DES.IsSemiWeakKey(rgbKey))
        {
            throw new CryptographicException(System.SR.Cryptography_InvalidKey_SemiWeak, "DES");
        }
        if (rgbIV == null)
        {
            if (Mode.UsesIv())
            {
                rgbIV = RandomNumberGenerator.GetBytes(8);
            }
        }
        else if (rgbIV.Length < 8)
        {
            throw new CryptographicException(System.SR.Cryptography_InvalidIVSize);
        }
        Internal.Cryptography.BasicSymmetricCipher cipher = new BasicSymmetricCipherCsp(26113, Mode, BlockSize / 8, rgbKey, 0, addNoSaltFlag: false, rgbIV, encrypting, FeedbackSize, this.GetPaddingSize(Mode, FeedbackSize));
        return Internal.Cryptography.UniversalCryptoTransform.Create(Padding, cipher, encrypting);
    }
}