37 lines
1.1 KiB
C#
37 lines
1.1 KiB
C#
using System;
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using Org.BouncyCastle.Crypto.Utilities;
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namespace Org.BouncyCastle.Crypto.Engines;
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public class XSalsa20Engine : Salsa20Engine
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{
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public override string AlgorithmName => "XSalsa20";
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protected override int NonceSize => 24;
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protected override void SetKey(byte[] keyBytes, byte[] ivBytes)
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{
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if (keyBytes == null)
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{
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throw new ArgumentException(AlgorithmName + " doesn't support re-init with null key");
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}
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if (keyBytes.Length != 32)
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{
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throw new ArgumentException(AlgorithmName + " requires a 256 bit key");
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}
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base.SetKey(keyBytes, ivBytes);
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Pack.LE_To_UInt32(ivBytes, 8, engineState, 8, 2);
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uint[] array = new uint[engineState.Length];
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Salsa20Engine.SalsaCore(20, engineState, array);
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engineState[1] = array[0] - engineState[0];
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engineState[2] = array[5] - engineState[5];
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engineState[3] = array[10] - engineState[10];
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engineState[4] = array[15] - engineState[15];
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engineState[11] = array[6] - engineState[6];
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engineState[12] = array[7] - engineState[7];
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engineState[13] = array[8] - engineState[8];
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engineState[14] = array[9] - engineState[9];
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Pack.LE_To_UInt32(ivBytes, 16, engineState, 6, 2);
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}
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}
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