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//========================================================================
//
// Decrypt.h
//
// Copyright 1996-2003 Glyph & Cog, LLC
//
//========================================================================
#ifndef DECRYPT_H
#define DECRYPT_H
#include <aconf.h>
#ifdef USE_GCC_PRAGMAS
#pragma interface
#endif
#include "gtypes.h"
#include "GString.h"
#include "Object.h"
#include "Stream.h"
//------------------------------------------------------------------------
// Decrypt
//------------------------------------------------------------------------
class Decrypt {
public:
// Generate a file key. The <fileKey> buffer must have space for at
// least 16 bytes. Checks <ownerPassword> and then <userPassword>
// and returns true if either is correct. Sets <ownerPasswordOk> if
// the owner password was correct. Either or both of the passwords
// may be NULL, which is treated as an empty string.
static GBool makeFileKey(int encVersion, int encRevision, int keyLength,
GString *ownerKey, GString *userKey,
GString *ownerEnc, GString *userEnc,
int permissions, GString *fileID,
GString *ownerPassword, GString *userPassword,
Guchar *fileKey, GBool encryptMetadata,
GBool *ownerPasswordOk);
private:
static void r6Hash(Guchar *key, int keyLen, const char *pwd, int pwdLen,
char *userKey);
static GBool makeFileKey2(int encVersion, int encRevision, int keyLength,
GString *ownerKey, GString *userKey,
int permissions, GString *fileID,
GString *userPassword, Guchar *fileKey,
GBool encryptMetadata);
};
//------------------------------------------------------------------------
// DecryptStream
//------------------------------------------------------------------------
struct DecryptRC4State {
Guchar state[256];
Guchar x, y;
int buf;
};
struct DecryptAESState {
Guint w[44];
Guchar state[16];
Guchar cbc[16];
Guchar buf[16];
int bufIdx;
};
struct DecryptAES256State {
Guint w[60];
Guchar state[16];
Guchar cbc[16];
Guchar buf[16];
int bufIdx;
};
class DecryptStream: public FilterStream {
public:
DecryptStream(Stream *strA, Guchar *fileKey,
CryptAlgorithm algoA, int keyLength,
int objNum, int objGen);
virtual ~DecryptStream();
virtual StreamKind getKind() { return strWeird; }
virtual void reset();
virtual int getChar();
virtual int lookChar();
virtual GBool isBinary(GBool last);
virtual Stream *getUndecodedStream() { return this; }
private:
CryptAlgorithm algo;
int objKeyLength;
Guchar objKey[32];
union {
DecryptRC4State rc4;
DecryptAESState aes;
DecryptAES256State aes256;
} state;
};
//------------------------------------------------------------------------
struct MD5State {
Gulong a, b, c, d;
Guchar buf[64];
int bufLen;
int msgLen;
Guchar digest[16];
};
extern void rc4InitKey(Guchar *key, int keyLen, Guchar *state);
extern Guchar rc4DecryptByte(Guchar *state, Guchar *x, Guchar *y, Guchar c);
void md5Start(MD5State *state);
void md5Append(MD5State *state, Guchar *data, int dataLen);
void md5Finish(MD5State *state);
extern void md5(Guchar *msg, int msgLen, Guchar *digest);
extern void aesKeyExpansion(DecryptAESState *s,
Guchar *objKey, int objKeyLen,
GBool decrypt);
extern void aesEncryptBlock(DecryptAESState *s, Guchar *in);
extern void aesDecryptBlock(DecryptAESState *s, Guchar *in, GBool last);
#endif
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