4.63

CPP/7zip/Crypto/WzAes.h

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+// Crypto/WzAes.h
+/*
+This code implements Brian Gladman's scheme
+specified in password Based File Encryption Utility:
+  - AES encryption (128,192,256-bit) in Counter (CTR) mode.
+  - HMAC-SHA1 authentication for encrypted data (10 bytes)
+  - Keys are derived by PPKDF2(RFC2898)-HMAC-SHA1 from ASCII password and
+    Salt (saltSize = aesKeySize / 2).
+  - 2 bytes contain Password Verifier's Code
+*/
+
+#ifndef __CRYPTO_WZ_AES_H
+#define __CRYPTO_WZ_AES_H
+
+extern "C"
+{
+#include "../../../C/Aes.h"
+}
+
+#include "Common/Buffer.h"
+#include "Common/MyCom.h"
+#include "Common/MyVector.h"
+
+#include "../ICoder.h"
+#include "../IPassword.h"
+
+#include "HmacSha1.h"
+
+namespace NCrypto {
+namespace NWzAes {
+
+const unsigned int kSaltSizeMax = 16;
+const unsigned int kMacSize = 10;
+
+const UInt32 kPasswordSizeMax = 99; // 128;
+
+// Password Verification Code Size
+const unsigned int kPwdVerifCodeSize = 2;
+
+class CKeyInfo
+{
+public:
+  Byte KeySizeMode; // 1 - 128-bit , 2 - 192-bit , 3 - 256-bit
+  Byte Salt[kSaltSizeMax];
+  Byte PwdVerifComputed[kPwdVerifCodeSize];
+
+  CByteBuffer Password;
+
+  UInt32 GetKeySize() const  { return (8 * (KeySizeMode & 3) + 8); }
+  UInt32 GetSaltSize() const { return (4 * (KeySizeMode & 3) + 4); }
+
+  CKeyInfo() { Init(); }
+  void Init() { KeySizeMode = 3; }
+};
+
+class CBaseCoder:
+  public ICompressFilter,
+  public ICryptoSetPassword,
+  public CMyUnknownImp
+{
+protected:
+  CKeyInfo _key;
+  UInt32 _counter[AES_BLOCK_SIZE / 4];
+  Byte _buffer[AES_BLOCK_SIZE];
+  NSha1::CHmac _hmac;
+  unsigned int _blockPos;
+  Byte _pwdVerifFromArchive[kPwdVerifCodeSize];
+
+  void EncryptData(Byte *data, UInt32 size);
+
+  CAes Aes;
+
+public:
+  STDMETHOD(Init)();
+  STDMETHOD_(UInt32, Filter)(Byte *data, UInt32 size) = 0;
+  
+  STDMETHOD(CryptoSetPassword)(const Byte *data, UInt32 size);
+
+  UInt32 GetHeaderSize() const { return _key.GetSaltSize() + kPwdVerifCodeSize; }
+};
+
+class CEncoder:
+  public CBaseCoder
+  // public ICompressWriteCoderProperties
+{
+public:
+  MY_UNKNOWN_IMP1(ICryptoSetPassword)
+  //  ICompressWriteCoderProperties
+  // STDMETHOD(WriteCoderProperties)(ISequentialOutStream *outStream);
+  STDMETHOD_(UInt32, Filter)(Byte *data, UInt32 size);
+  HRESULT WriteHeader(ISequentialOutStream *outStream);
+  HRESULT WriteFooter(ISequentialOutStream *outStream);
+  bool SetKeyMode(Byte mode)
+  {
+    if (mode < 1 || mode > 3)
+      return false;
+    _key.KeySizeMode = mode;
+    return true;
+  }
+};
+
+class CDecoder:
+  public CBaseCoder,
+  public ICompressSetDecoderProperties2
+{
+public:
+  MY_UNKNOWN_IMP2(
+      ICryptoSetPassword,
+      ICompressSetDecoderProperties2)
+  STDMETHOD_(UInt32, Filter)(Byte *data, UInt32 size);
+  STDMETHOD(SetDecoderProperties2)(const Byte *data, UInt32 size);
+  HRESULT ReadHeader(ISequentialInStream *inStream);
+  bool CheckPasswordVerifyCode();
+  HRESULT CheckMac(ISequentialInStream *inStream, bool &isOK);
+};
+
+}}
+
+#endif