96 lines
2.1 KiB
C#
96 lines
2.1 KiB
C#
using System;
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namespace Org.BouncyCastle.Crypto.Parameters
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{
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public class DesEdeParameters
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: DesParameters
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{
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/*
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* DES-EDE Key length in bytes.
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*/
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public const int DesEdeKeyLength = 24;
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private static byte[] FixKey(
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byte[] key,
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int keyOff,
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int keyLen)
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{
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byte[] tmp = new byte[24];
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switch (keyLen)
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{
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case 16:
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Array.Copy(key, keyOff, tmp, 0, 16);
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Array.Copy(key, keyOff, tmp, 16, 8);
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break;
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case 24:
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Array.Copy(key, keyOff, tmp, 0, 24);
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break;
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default:
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throw new ArgumentException("Bad length for DESede key: " + keyLen, "keyLen");
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}
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if (IsWeakKey(tmp))
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throw new ArgumentException("attempt to create weak DESede key");
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return tmp;
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}
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public DesEdeParameters(
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byte[] key)
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: base(FixKey(key, 0, key.Length))
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{
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}
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public DesEdeParameters(
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byte[] key,
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int keyOff,
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int keyLen)
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: base(FixKey(key, keyOff, keyLen))
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{
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}
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/**
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* return true if the passed in key is a DES-EDE weak key.
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*
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* @param key bytes making up the key
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* @param offset offset into the byte array the key starts at
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* @param length number of bytes making up the key
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*/
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public static bool IsWeakKey(
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byte[] key,
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int offset,
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int length)
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{
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for (int i = offset; i < length; i += DesKeyLength)
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{
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if (DesParameters.IsWeakKey(key, i))
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{
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return true;
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}
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}
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return false;
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}
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/**
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* return true if the passed in key is a DES-EDE weak key.
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*
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* @param key bytes making up the key
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* @param offset offset into the byte array the key starts at
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*/
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public static new bool IsWeakKey(
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byte[] key,
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int offset)
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{
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return IsWeakKey(key, offset, key.Length - offset);
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}
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public static new bool IsWeakKey(
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byte[] key)
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{
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return IsWeakKey(key, 0, key.Length);
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}
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}
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}
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