43 lines
1.2 KiB
C#
43 lines
1.2 KiB
C#
// <copyright file="Xor3Encryptor.cs" company="MUnique">
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// Licensed under the MIT License. See LICENSE file in the project root for full license information.
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// </copyright>
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namespace MUnique.OpenMU.Network.Xor;
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/// <summary>
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/// An encryptor which XOR-encrypts data using a 3-byte key.
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/// </summary>
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public class Xor3Encryptor : ISpanEncryptor
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{
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private readonly byte[] _xor3Keys;
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private readonly int _startOffset;
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/// <summary>
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/// Initializes a new instance of the <see cref="Xor3Encryptor"/> class.
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/// </summary>
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/// <param name="startOffset">The start offset.</param>
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public Xor3Encryptor(int startOffset)
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{
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this._startOffset = startOffset;
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this._xor3Keys = DefaultKeys.Xor3Keys;
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}
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/// <inheritdoc/>
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public void Encrypt(Span<byte> data)
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{
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this.InternalEncrypt(data.Slice(this._startOffset));
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}
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/// <summary>
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/// Internal encrypt function. XORs each byte with one byte of the 3-byte key.
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/// </summary>
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/// <param name="data">The data.</param>
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protected void InternalEncrypt(Span<byte> data)
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{
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for (var i = 0; i < data.Length; i++)
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{
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data[i] ^= this._xor3Keys[i % 3];
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}
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}
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} |