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/*
* rsyncrypto - an rsync friendly encryption
* Copyright (C) 2006-2008 Shachar Shemesh for Lingnu Open Source Consulting ltd.
*
* This program 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 of the License, or
* (at your option) any later version.
*
* This program 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 this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* In addition, as a special exception, the rsyncrypto authors give permission
* to link the code of this program with the OpenSSL library (or with modified
* versions of OpenSSL that use the same license as OpenSSL), and distribute
* linked combinations including the two. You must obey the GNU General Public
* License in all respects for all of the code used other than OpenSSL. If you
* modify this file, you may extend this exception to your version of the file,
* but you are not obligated to do so. If you do not wish to do so, delete this
* exception statement from your version.
*
* The project's homepage is at http://rsyncrypto.lingnu.com/
*/
#include "precomp.h"
#include "rsyncrypto.h"
#include "crypt_key.h"
#include "aes_crypt.h"
const uint32_t key::VERSION_MAGIC_1=0xD657EA1Cul;
const uint32_t key::VERSION_MAGIC_CUR=VERSION_MAGIC_1;
key *key::read_key( const unsigned char *buffer )
{
const ext_key_header *buff=reinterpret_cast<const ext_key_header *>(buffer);
if( buff->version!=htonl(VERSION_MAGIC_1) )
throw rscerror("Invalid version magic");
std::auto_ptr<key> ret;
switch( static_cast<CYPHER_TYPES>(buff->cypher) )
{
case CYPHER_AES:
ret=std::auto_ptr<key>(new aes_key( ntohs(buff->key_size), ntohl(buff->sum_span), ntohl(buff->sum_mod),
ntohl(buff->sum_min_dist), buffer+sizeof(*buff) ));
break;
default:
throw rscerror("Invalid block cypher");
}
return ret.release();
}
key *key::new_key( CYPHER_TYPES cypher, size_t keybits, uint32_t sum_span, uint32_t sum_mod,
uint32_t sum_min_dist )
{
std::auto_ptr<key> ret;
switch( static_cast<CYPHER_TYPES>(cypher) ) {
case CYPHER_AES:
ret=std::auto_ptr<key>(new aes_key( keybits, sum_span, sum_mod, sum_min_dist ));
break;
default:
throw rscerror("Invalid block cypher");
}
return ret.release();
}
size_t key::export_key( void *buffer ) const
{
struct ext_key_header *export_buff=static_cast<ext_key_header *>(buffer);
bzero(export_buff, sizeof(*export_buff));
export_buff->version=htonl(header.version);
export_buff->cypher=htons(header.cypher);
export_buff->key_size=htons(header.key_size);
export_buff->sum_span=htonl(header.sum_span);
export_buff->sum_mod=htonl(header.sum_mod);
export_buff->sum_min_dist=htonl(header.sum_min_dist);
return key::exported_length();
}
void key::pad_area( unsigned char *buffer, size_t size ) const
{
std::auto_ptr<key> pad_key(gen_pad_key());
bzero( buffer, size );
pad_key->init_encrypt();
const size_t blocksize=block_size();
for( unsigned int i=0; i<size; i+=blocksize )
pad_key->encrypt_block( buffer+i, blocksize );
}
void key::init_encrypt()
{
ptbuf_loc=0;
ptbuf_sum=0;
ptbuf_count=0;
ptbuf_sub=false;
ptbuf_may_rotate=false;
}
bool key::calc_boundry( unsigned char data )
{
ptbuf_sum+=data;
if( ptbuf_sub )
ptbuf_sum-=plaintext_buffer[ptbuf_loc];
plaintext_buffer[ptbuf_loc]=data;
if( (++ptbuf_loc)==header.sum_span ) {
ptbuf_loc=0;
ptbuf_sub=true;
}
if( (ptbuf_count++)==header.sum_min_dist ) {
ptbuf_may_rotate=true;
}
if( ptbuf_may_rotate && (ptbuf_sum%header.sum_mod)==0 ) {
if( ARG(verbosity).count>=3 ) {
std::cerr<<"Rotated "<<ptbuf_count<<std::endl;
}
return true;
}
return false;
}
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