DES.cs

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using System.Buffers.Binary;
using System.ComponentModel;
using System.Diagnostics.CodeAnalysis;
using System.Runtime.Versioning;
using Internal.Cryptography;
 
namespace System.Security.Cryptography;
 
[UnsupportedOSPlatform("browser")]
[EditorBrowsable(EditorBrowsableState.Never)]
public abstract class DES : SymmetricAlgorithm
{
    private static readonly KeySizes[] s_legalBlockSizes = new KeySizes[1]
    {
        new KeySizes(64, 64, 0)
    };
 
    private static readonly KeySizes[] s_legalKeySizes = new KeySizes[1]
    {
        new KeySizes(64, 64, 0)
    };
 
    public override byte[] Key
    {
        get
        {
            byte[] key = base.Key;
            while (IsWeakKey(key) || IsSemiWeakKey(key))
            {
                GenerateKey();
                key = base.Key;
            }
            return key;
        }
        set
        {
            if (value == null)
            {
                throw new ArgumentNullException("value");
            }
            if (!(value.Length * 8).IsLegalSize(s_legalKeySizes))
            {
                throw new ArgumentException(System.SR.Cryptography_InvalidKeySize);
            }
            if (IsWeakKey(value))
            {
                throw new CryptographicException(System.SR.Cryptography_InvalidKey_Weak, "DES");
            }
            if (IsSemiWeakKey(value))
            {
                throw new CryptographicException(System.SR.Cryptography_InvalidKey_SemiWeak, "DES");
            }
            base.Key = value;
        }
    }
 
    protected DES()
    {
        LegalBlockSizesValue = s_legalBlockSizes.CloneKeySizesArray();
        LegalKeySizesValue = s_legalKeySizes.CloneKeySizesArray();
        KeySizeValue = 64;
        BlockSizeValue = 64;
        FeedbackSizeValue = BlockSizeValue;
    }
 
    public new static DES Create()
    {
        return new DesImplementation();
    }
 
    [RequiresUnreferencedCode("The default algorithm implementations might be removed, use strong type references like 'RSA.Create()' instead.")]
    public new static DES? Create(string algName)
    {
        return (DES)CryptoConfig.CreateFromName(algName);
    }
 
    public static bool IsWeakKey(byte[] rgbKey)
    {
        if (!IsLegalKeySize(rgbKey))
        {
            throw new CryptographicException(System.SR.Cryptography_InvalidKeySize);
        }
        byte[] array = rgbKey.FixupKeyParity();
        ulong num = BinaryPrimitives.ReadUInt64BigEndian(array);
        if (num == 72340172838076673L || num == 18374403900871474942uL || num == 2242545357694045710L || num == 16204198716015505905uL)
        {
            return true;
        }
        return false;
    }
 
    public static bool IsSemiWeakKey(byte[] rgbKey)
    {
        if (!IsLegalKeySize(rgbKey))
        {
            throw new CryptographicException(System.SR.Cryptography_InvalidKeySize);
        }
        byte[] array = rgbKey.FixupKeyParity();
        ulong num = BinaryPrimitives.ReadUInt64BigEndian(array);
        if (num == 143554428589179390L || num == 18303189645120372225uL || num == 2296870857142767345L || num == 16149873216566784270uL || num == 135110050437988849L || num == 16141428838415593729uL || num == 2305315235293957886L || num == 18311634023271562766uL || num == 80784550989267214L || num == 2234100979542855169L || num == 16212643094166696446uL || num == 18365959522720284401uL)
        {
            return true;
        }
        return false;
    }
 
    private static bool IsLegalKeySize(byte[] rgbKey)
    {
        if (rgbKey != null && rgbKey.Length == 8)
        {
            return true;
        }
        return false;
    }
}