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|
/*****************************************************************
|
| AP4 - Stream Cipher
|
| Copyright 2002-2008 Axiomatic Systems, LLC
|
|
| This file is part of Bento4/AP4 (MP4 Atom Processing Library).
|
| Unless you have obtained Bento4 under a difference license,
| this version of Bento4 is Bento4|GPL.
| Bento4|GPL is free software; you can redistribute it and/or modify
| it under the terms of the GNU General Public License as published by
| the Free Software Foundation; either version 2, or (at your option)
| any later version.
|
| Bento4|GPL is distributed in the hope that it will be useful,
| but WITHOUT ANY WARRANTY; without even the implied warranty of
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
| GNU General Public License for more details.
|
| You should have received a copy of the GNU General Public License
| along with Bento4|GPL; see the file COPYING. If not, write to the
| Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA
| 02111-1307, USA.
|
****************************************************************/
#ifndef _AP4_STREAM_CIPHER_H_
#define _AP4_STREAM_CIPHER_H_
/*----------------------------------------------------------------------
| includes
+---------------------------------------------------------------------*/
#include "Ap4Protection.h"
#include "Ap4Results.h"
#include "Ap4Types.h"
/*----------------------------------------------------------------------
| constants
+---------------------------------------------------------------------*/
// we only support this for now
const unsigned int AP4_CIPHER_BLOCK_SIZE = 16;
/*----------------------------------------------------------------------
| AP4_StreamCipher interface
+---------------------------------------------------------------------*/
class AP4_StreamCipher
{
public:
// methods
virtual ~AP4_StreamCipher() {}
virtual AP4_UI64 GetStreamOffset() = 0;
virtual AP4_Result ProcessBuffer(const AP4_UI08* in,
AP4_Size in_size,
AP4_UI08* out,
AP4_Size* out_size,
bool is_last_buffer = false) = 0;
// preroll gives the number of bytes you have to preroll your input and feed
// it through ProcessBuffer (in one shot) in order to be able to spit out
// the output at the given offset
virtual AP4_Result SetStreamOffset(AP4_UI64 offset,
AP4_Cardinal* preroll) = 0;
virtual AP4_Result SetIV(const AP4_UI08* iv) = 0;
virtual const AP4_UI08* GetIV() = 0;
};
/*----------------------------------------------------------------------
| AP4_CtrStreamCipher
+---------------------------------------------------------------------*/
class AP4_CtrStreamCipher : public AP4_StreamCipher
{
public:
// methods
/**
* The block cipher is passed with transfer of ownership (it will
* be destroyed when this object is destroyed).
*/
AP4_CtrStreamCipher(AP4_BlockCipher* block_cipher,
AP4_Size counter_size);
~AP4_CtrStreamCipher();
// AP4_StreamCipher implementation
virtual AP4_Result SetStreamOffset(AP4_UI64 offset,
AP4_Cardinal* preroll = NULL);
virtual AP4_UI64 GetStreamOffset() { return m_StreamOffset; }
virtual AP4_Result ProcessBuffer(const AP4_UI08* in,
AP4_Size in_size,
AP4_UI08* out,
AP4_Size* out_size = NULL,
bool is_last_buffer = false);
virtual AP4_Result SetIV(const AP4_UI08* iv);
virtual const AP4_UI08* GetIV() { return m_IV; }
private:
// methods
void ComputeCounter(AP4_UI64 stream_offset,
AP4_UI08 counter_block[AP4_CIPHER_BLOCK_SIZE]);
// members
AP4_UI64 m_StreamOffset;
AP4_Size m_CounterSize;
AP4_UI08 m_IV[AP4_CIPHER_BLOCK_SIZE];
AP4_UI08 m_CacheBlock[AP4_CIPHER_BLOCK_SIZE];
bool m_CacheValid;
AP4_BlockCipher* m_BlockCipher;
};
/*----------------------------------------------------------------------
| AP4_CbcStreamCipher
+---------------------------------------------------------------------*/
class AP4_CbcStreamCipher : public AP4_StreamCipher
{
public:
// methods
/**
* The block cipher is passed with transfer of ownership (it will
* be destroyed when this object is destroyed).
*/
AP4_CbcStreamCipher(AP4_BlockCipher* block_cipher);
~AP4_CbcStreamCipher();
// AP4_StreamCipher implementation
virtual AP4_Result SetStreamOffset(AP4_UI64 offset,
AP4_Cardinal* preroll);
virtual AP4_UI64 GetStreamOffset() { return m_StreamOffset; }
virtual AP4_Result ProcessBuffer(const AP4_UI08* in,
AP4_Size in_size,
AP4_UI08* out,
AP4_Size* out_size,
bool is_last_buffer = false);
virtual AP4_Result SetIV(const AP4_UI08* iv);
virtual const AP4_UI08* GetIV() { return m_Iv; };
private:
// members
AP4_UI64 m_StreamOffset;
AP4_Cardinal m_OutputSkip;
AP4_UI08 m_InBlock[AP4_CIPHER_BLOCK_SIZE];
AP4_Cardinal m_InBlockFullness;
AP4_UI08 m_ChainBlock[AP4_CIPHER_BLOCK_SIZE];
AP4_Cardinal m_ChainBlockFullness;
AP4_UI08 m_Iv[AP4_CIPHER_BLOCK_SIZE];
AP4_BlockCipher* m_BlockCipher;
bool m_Eos;
// methods
AP4_Result EncryptBuffer(const AP4_UI08* in,
AP4_Size in_size,
AP4_UI08* out,
AP4_Size* out_size,
bool is_last_buffer);
AP4_Result DecryptBuffer(const AP4_UI08* in,
AP4_Size in_size,
AP4_UI08* out,
AP4_Size* out_size,
bool is_last_buffer);
};
#endif // _AP4_STREAM_CIPHER_H_
|
