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110 lines
2.5 KiB
110 lines
2.5 KiB
namespace com.hitrust.Security.Cryptography
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{
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using System;
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using System.Security.Cryptography;
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public abstract class RC4 : SymmetricAlgorithm
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{
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private RNGCryptoServiceProvider m_RNG;
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protected RC4()
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{
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base.KeySizeValue = 0x80;
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}
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public new static RC4 Create()
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{
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return Create("ARCFOUR");
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}
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public new static RC4 Create(string AlgName)
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{
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try {
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if ((AlgName.ToUpper() == "RC4") || (AlgName.ToLower() == "org.mentalis.security.cryptography.rc4cryptoserviceprovider")) {
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return new RC4CryptoServiceProvider();
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}
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if ((AlgName.ToUpper() == "ARCFOUR") || (AlgName.ToLower() == "org.mentalis.security.cryptography.arcfourmanaged")) {
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return new ARCFourManaged();
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}
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} catch {}
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return null;
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}
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public override void GenerateIV() {}
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public override void GenerateKey()
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{
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byte[] key = new byte[this.KeySize / 8];
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this.GetRNGCSP().GetBytes(key);
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this.Key = key;
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}
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protected RNGCryptoServiceProvider GetRNGCSP()
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{
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if (this.m_RNG == null) {
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this.m_RNG = new RNGCryptoServiceProvider();
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}
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return this.m_RNG;
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}
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public override int BlockSize
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{
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get { return 8; }
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set
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{
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if ((value != 8) && (value != 0)) {
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throw new CryptographicException("RC4 is a stream cipher, not a block cipher.");
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}
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}
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}
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public override int FeedbackSize
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{
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get { throw new CryptographicException("RC4 doesn't use the feedback size property."); }
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set { throw new CryptographicException("RC4 doesn't use the feedback size property."); }
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}
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public override byte[] IV
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{
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get { return new byte[1]; }
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set
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{
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if ((value != null) && (value.Length > 1)) {
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throw new CryptographicException("RC4 doesn't use an Initialization Vector.");
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}
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}
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}
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public override KeySizes[] LegalBlockSizes
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{
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get { return new KeySizes[] {new KeySizes(8, 8, 0)}; }
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}
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public override KeySizes[] LegalKeySizes
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{
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get { return new KeySizes[] {new KeySizes(8, 0x800, 8)}; }
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}
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public override CipherMode Mode
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{
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get { return CipherMode.OFB; }
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set
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{
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if (value != CipherMode.OFB) {
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throw new CryptographicException("RC4 only supports OFB.");
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}
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}
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}
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public override PaddingMode Padding
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{
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get { return PaddingMode.None; }
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set
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{
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if (value != PaddingMode.None) {
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throw new CryptographicException("RC4 is a stream cipher, not a block cipher.");
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}
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}
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}
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}
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}
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