332 lines
8.1 KiB
C
332 lines
8.1 KiB
C
/*
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* Copyright (C) 1998,1999,2000,2001 Nikos Mavroyanopoulos
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*
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* This library is free software; you can redistribute it and/or modify it
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* under the terms of the GNU Library General Public License as published
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* by the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 02111-1307, USA.
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*/
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#include <libdefs.h>
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#include <mcrypt_modules.h>
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#define _init_mcrypt ncfb_LTX__init_mcrypt
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#define _mcrypt_set_state ncfb_LTX__mcrypt_set_state
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#define _mcrypt_get_state ncfb_LTX__mcrypt_get_state
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#define _end_mcrypt ncfb_LTX__end_mcrypt
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#define _mcrypt ncfb_LTX__mcrypt
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#define _mdecrypt ncfb_LTX__mdecrypt
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#define _has_iv ncfb_LTX__has_iv
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#define _is_block_mode ncfb_LTX__is_block_mode
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#define _is_block_algorithm_mode ncfb_LTX__is_block_algorithm_mode
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#define _mcrypt_get_modes_name ncfb_LTX__mcrypt_get_modes_name
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#define _mcrypt_mode_get_size ncfb_LTX__mcrypt_mode_get_size
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#define _mcrypt_mode_version ncfb_LTX__mcrypt_mode_version
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typedef struct ncfb_buf {
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byte* enc_s_register;
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byte* s_register;
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int s_register_pos;
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int blocksize;
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} nCFB_BUFFER;
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/* nCFB MODE */
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int _init_mcrypt( nCFB_BUFFER* buf, void *key, int lenofkey, void *IV, int size)
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{
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buf->enc_s_register = buf->s_register = NULL;
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buf->s_register_pos = 0;
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buf->blocksize = size;
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/* For cfb */
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buf->enc_s_register=malloc( size);
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if (buf->enc_s_register==NULL) goto freeall;
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buf->s_register=malloc( size);
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if (buf->s_register==NULL) goto freeall;
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if (IV!=NULL) {
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memcpy(buf->enc_s_register, IV, size);
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memcpy(buf->s_register, IV, size);
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} else {
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memset(buf->enc_s_register, 0, size);
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memset(buf->s_register, 0, size);
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}
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/* End ncfb */
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return 0;
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freeall:
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free(buf->enc_s_register);
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free(buf->s_register);
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return -1;
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}
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int _mcrypt_set_state( nCFB_BUFFER* buf, byte *IV, int size)
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{
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buf->s_register_pos = IV[0];
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memcpy(buf->enc_s_register, &IV[1], size-1);
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memcpy(buf->s_register, &IV[1], size-1);
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return 0;
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}
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int _mcrypt_get_state( nCFB_BUFFER* buf, byte *IV, int *size)
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{
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if (*size < buf->blocksize + 1) {
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*size = buf->blocksize + 1;
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return -1;
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}
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*size = buf->blocksize + 1;
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IV[0] = buf->s_register_pos;
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memcpy( &IV[1], buf->s_register, buf->blocksize);
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return 0;
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}
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void _end_mcrypt( nCFB_BUFFER* buf) {
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free(buf->enc_s_register);
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free(buf->s_register);
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}
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inline static
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void xor_stuff_en( nCFB_BUFFER *buf, void* akey, void (*func)(void*,void*), byte* plain, int blocksize, int xor_size)
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{
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void (*_mcrypt_block_encrypt) (void *, void *);
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_mcrypt_block_encrypt = func;
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if (xor_size == blocksize) {
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if (buf->s_register_pos == 0) {
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memcpy(buf->enc_s_register, buf->s_register, blocksize);
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_mcrypt_block_encrypt(akey, buf->enc_s_register);
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memxor( plain, buf->enc_s_register, blocksize);
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memcpy(buf->s_register, plain, blocksize);
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} else {
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int size = blocksize - buf->s_register_pos;
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memxor( plain, &buf->enc_s_register[buf->s_register_pos],
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size);
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memcpy(buf->enc_s_register, buf->s_register, blocksize);
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_mcrypt_block_encrypt(akey, buf->enc_s_register);
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memxor( &plain[size], buf->enc_s_register,
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buf->s_register_pos);
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memcpy( &buf->s_register[size],
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plain, buf->s_register_pos);
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/* buf->s_register_pos remains the same */
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}
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} else { /* xor_size != blocksize */
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if (buf->s_register_pos == 0) {
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memcpy(buf->enc_s_register, buf->s_register, blocksize);
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_mcrypt_block_encrypt(akey, buf->enc_s_register);
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memxor( plain, buf->enc_s_register, xor_size);
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memcpy(buf->s_register, plain, xor_size);
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buf->s_register_pos = xor_size;
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} else {
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int size = blocksize - buf->s_register_pos;
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int min_size = size < xor_size ? size: xor_size;
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memxor( plain, &buf->enc_s_register[buf->s_register_pos],
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min_size);
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memcpy( &buf->s_register[buf->s_register_pos], plain, min_size);
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buf->s_register_pos += min_size;
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if (min_size >= xor_size)
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return;
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memcpy(buf->enc_s_register, buf->s_register, blocksize);
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_mcrypt_block_encrypt(akey, buf->enc_s_register);
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memxor( &plain[min_size], buf->s_register,
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xor_size - min_size);
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buf->s_register_pos = xor_size - min_size;
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memcpy(buf->s_register, plain, xor_size - min_size);
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}
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}
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return;
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}
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inline static
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void xor_stuff_de( nCFB_BUFFER *buf, void* akey, void (*func)(void*,void*), byte* cipher, int blocksize, int xor_size)
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{
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void (*_mcrypt_block_encrypt) (void *, void *);
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_mcrypt_block_encrypt = func;
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if (xor_size == blocksize) {
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if (buf->s_register_pos == 0) {
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memcpy(buf->enc_s_register, buf->s_register, blocksize);
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_mcrypt_block_encrypt(akey, buf->enc_s_register);
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memcpy(buf->s_register, cipher, blocksize);
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memxor( cipher, buf->enc_s_register, blocksize);
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} else {
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int size = blocksize - buf->s_register_pos;
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memxor( cipher, &buf->enc_s_register[buf->s_register_pos],
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size);
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memcpy(buf->enc_s_register, buf->s_register, blocksize);
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_mcrypt_block_encrypt(akey, buf->enc_s_register);
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memcpy( &buf->s_register[size],
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cipher, buf->s_register_pos);
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memxor( &cipher[size], buf->enc_s_register,
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buf->s_register_pos);
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/* buf->s_register_pos remains the same */
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}
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} else { /* xor_size != blocksize */
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if (buf->s_register_pos == 0) {
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memcpy(buf->enc_s_register, buf->s_register, blocksize);
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_mcrypt_block_encrypt(akey, buf->enc_s_register);
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memcpy(buf->s_register, cipher, xor_size);
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memxor( cipher, buf->enc_s_register, xor_size);
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buf->s_register_pos = xor_size;
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} else {
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int size = blocksize - buf->s_register_pos;
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int min_size = size < xor_size ? size: xor_size;
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memxor( cipher, &buf->enc_s_register[buf->s_register_pos],
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min_size);
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memcpy( &buf->s_register[buf->s_register_pos], cipher, min_size);
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buf->s_register_pos += min_size;
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if (min_size >= xor_size)
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return;
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memcpy(buf->enc_s_register, buf->s_register, blocksize);
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_mcrypt_block_encrypt(akey, buf->enc_s_register);
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memcpy(buf->s_register, cipher, xor_size - min_size);
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memxor( &cipher[min_size], buf->s_register,
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xor_size - min_size);
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buf->s_register_pos = xor_size - min_size;
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}
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}
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return;
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}
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int _mcrypt( nCFB_BUFFER* buf,void *plaintext, int len, int blocksize, void* akey, void (*func)(void*,void*), void (*func2)(void*,void*))
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{ /* plaintext is n*blocksize bytes (nbit cfb) */
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byte* plain;
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int i, j=0;
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void (*_mcrypt_block_encrypt) (void *, void *);
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int modlen;
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_mcrypt_block_encrypt = func;
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plain = plaintext;
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for (j = 0; j < len / blocksize; j++) {
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xor_stuff_en( buf, akey, func, plain, blocksize, blocksize);
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plain += blocksize;
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}
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modlen = len % blocksize;
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if (modlen > 0) {
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xor_stuff_en( buf, akey, func, plain, blocksize, modlen);
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}
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return 0;
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}
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int _mdecrypt( nCFB_BUFFER* buf,void *plaintext, int len, int blocksize, void* akey, void (*func)(void*,void*), void (*func2)(void*,void*))
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{ /* plaintext is n*blocksize bytes (nbit cfb) */
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byte* plain;
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int i, j=0;
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void (*_mcrypt_block_encrypt) (void *, void *);
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int modlen;
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_mcrypt_block_encrypt = func;
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plain = plaintext;
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for (j = 0; j < len / blocksize; j++) {
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xor_stuff_de( buf, akey, func, plain, blocksize, blocksize);
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plain += blocksize;
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}
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modlen = len % blocksize;
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if (modlen > 0) {
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xor_stuff_de( buf, akey, func, plain, blocksize, modlen);
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}
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return 0;
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}
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int _has_iv() { return 1; }
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int _is_block_mode() { return 0; }
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int _is_block_algorithm_mode() { return 1; }
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const char *_mcrypt_get_modes_name() { return "nCFB";}
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int _mcrypt_mode_get_size () {return sizeof(nCFB_BUFFER);}
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word32 _mcrypt_mode_version() {
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return 20020307;
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}
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#ifdef WIN32
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# ifdef USE_LTDL
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WIN32DLL_DEFINE int main (void)
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{
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/* empty main function to avoid linker error (see cygwin FAQ) */
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}
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# endif
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#endif
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