arospdf/xpdf/Decrypt.h

   1 //========================================================================
   2 //
   3 // Decrypt.h
   4 //
   5 // Copyright 1996-2003 Glyph & Cog, LLC
   6 //
   7 //========================================================================
   8
   9 #ifndef DECRYPT_H
  10 #define DECRYPT_H
  11
  12 #include <aconf.h>
  13
  14 #ifdef USE_GCC_PRAGMAS
  15 #pragma interface
  16 #endif
  17
  18 #include "gtypes.h"
  19 #include "GString.h"
  20 #include "Object.h"
  21 #include "Stream.h"
  22
  23 //------------------------------------------------------------------------
  24 // Decrypt
  25 //------------------------------------------------------------------------
  26
  27 class Decrypt {
  28 public:
  29
  30   // Generate a file key.  The <fileKey> buffer must have space for at
  31   // least 16 bytes.  Checks <ownerPassword> and then <userPassword>
  32   // and returns true if either is correct.  Sets <ownerPasswordOk> if
  33   // the owner password was correct.  Either or both of the passwords
  34   // may be NULL, which is treated as an empty string.
  35   static GBool makeFileKey(int encVersion, int encRevision, int keyLength,
  36                            GString *ownerKey, GString *userKey,
  37                            int permissions, GString *fileID,
  38                            GString *ownerPassword, GString *userPassword,
  39                            Guchar *fileKey, GBool encryptMetadata,
  40                            GBool *ownerPasswordOk);
  41
  42 private:
  43
  44   static GBool makeFileKey2(int encVersion, int encRevision, int keyLength,
  45                             GString *ownerKey, GString *userKey,
  46                             int permissions, GString *fileID,
  47                             GString *userPassword, Guchar *fileKey,
  48                             GBool encryptMetadata);
  49 };
  50
  51 //------------------------------------------------------------------------
  52 // DecryptStream
  53 //------------------------------------------------------------------------
  54
  55 struct DecryptRC4State {
  56   Guchar state[256];
  57   Guchar x, y;
  58   int buf;
  59 };
  60
  61 struct DecryptAESState {
  62   Guint w[44];
  63   Guchar state[16];
  64   Guchar cbc[16];
  65   Guchar buf[16];
  66   int bufIdx;
  67 };
  68
  69 class DecryptStream: public FilterStream {
  70 public:
  71
  72   DecryptStream(Stream *strA, Guchar *fileKey,
  73                 CryptAlgorithm algoA, int keyLength,
  74                 int objNum, int objGen);
  75   virtual ~DecryptStream();
  76   virtual StreamKind getKind() { return strWeird; }
  77   virtual void reset();
  78   virtual int getChar();
  79   virtual int lookChar();
  80   virtual GBool isBinary(GBool last);
  81   virtual Stream *getUndecodedStream() { return this; }
  82
  83 private:
  84
  85   CryptAlgorithm algo;
  86   int objKeyLength;
  87   Guchar objKey[16 + 9];
  88
  89   union {
  90     DecryptRC4State rc4;
  91     DecryptAESState aes;
  92   } state;
  93 };
  94
  95 #endif