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