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/*
Unix SMB/CIFS implementation.
An implementation of the arcfour algorithm
Copyright (C) Andrew Tridgell 1998
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., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include "includes.h"
#include "lib/crypto/crypto.h"
/* initialise the arcfour sbox with key */
void arcfour_init(struct arcfour_state *state, const DATA_BLOB *key)
{
int ind;
uint8_t j = 0;
for (ind = 0; ind < sizeof(state->sbox); ind++) {
state->sbox[ind] = (uint8_t)ind;
}
for (ind = 0; ind < sizeof(state->sbox); ind++) {
uint8_t tc;
j += (state->sbox[ind] + key->data[ind%key->length]);
tc = state->sbox[ind];
state->sbox[ind] = state->sbox[j];
state->sbox[j] = tc;
}
state->index_i = 0;
state->index_j = 0;
}
/* crypt the data with arcfour */
void arcfour_crypt_sbox(struct arcfour_state *state, uint8_t *data, int len)
{
int ind;
for (ind = 0; ind < len; ind++) {
uint8_t tc;
uint8_t t;
state->index_i++;
state->index_j += state->sbox[state->index_i];
tc = state->sbox[state->index_i];
state->sbox[state->index_i] = state->sbox[state->index_j];
state->sbox[state->index_j] = tc;
t = state->sbox[state->index_i] + state->sbox[state->index_j];
data[ind] = data[ind] ^ state->sbox[t];
}
}
/*
arcfour encryption with a blob key
*/
void arcfour_crypt_blob(uint8_t *data, int len, const DATA_BLOB *key)
{
struct arcfour_state state;
arcfour_init(&state, key);
arcfour_crypt_sbox(&state, data, len);
}
/*
a variant that assumes a 16 byte key. This should be removed
when the last user is gone
*/
void arcfour_crypt(uint8_t *data, const uint8_t keystr[16], int len)
{
DATA_BLOB key = data_blob(keystr, 16);
arcfour_crypt_blob(data, len, &key);
data_blob_free(&key);
}
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