1/*
2   Unix SMB/CIFS implementation.
3
4   An implementation of the arcfour algorithm
5
6   Copyright (C) Andrew Tridgell 1998
7
8   This program is free software; you can redistribute it and/or modify
9   it under the terms of the GNU General Public License as published by
10   the Free Software Foundation; either version 3 of the License, or
11   (at your option) any later version.
12
13   This program is distributed in the hope that it will be useful,
14   but WITHOUT ANY WARRANTY; without even the implied warranty of
15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16   GNU General Public License for more details.
17
18   You should have received a copy of the GNU General Public License
19   along with this program.  If not, see <http://www.gnu.org/licenses/>.
20*/
21
22#include "includes.h"
23#include "../lib/crypto/arcfour.h"
24
25/* initialise the arcfour sbox with key */
26_PUBLIC_ void arcfour_init(struct arcfour_state *state, const DATA_BLOB *key)
27{
28	int ind;
29	uint8_t j = 0;
30	for (ind = 0; ind < sizeof(state->sbox); ind++) {
31		state->sbox[ind] = (uint8_t)ind;
32	}
33
34	for (ind = 0; ind < sizeof(state->sbox); ind++) {
35		uint8_t tc;
36
37		j += (state->sbox[ind] + key->data[ind%key->length]);
38
39		tc = state->sbox[ind];
40		state->sbox[ind] = state->sbox[j];
41		state->sbox[j] = tc;
42	}
43	state->index_i = 0;
44	state->index_j = 0;
45}
46
47/* crypt the data with arcfour */
48_PUBLIC_ void arcfour_crypt_sbox(struct arcfour_state *state, uint8_t *data, int len)
49{
50	int ind;
51
52	for (ind = 0; ind < len; ind++) {
53		uint8_t tc;
54		uint8_t t;
55
56		state->index_i++;
57		state->index_j += state->sbox[state->index_i];
58
59		tc = state->sbox[state->index_i];
60		state->sbox[state->index_i] = state->sbox[state->index_j];
61		state->sbox[state->index_j] = tc;
62
63		t = state->sbox[state->index_i] + state->sbox[state->index_j];
64		data[ind] = data[ind] ^ state->sbox[t];
65	}
66}
67
68/*
69  arcfour encryption with a blob key
70*/
71_PUBLIC_ void arcfour_crypt_blob(uint8_t *data, int len, const DATA_BLOB *key)
72{
73	struct arcfour_state state;
74	arcfour_init(&state, key);
75	arcfour_crypt_sbox(&state, data, len);
76}
77
78/*
79  a variant that assumes a 16 byte key. This should be removed
80  when the last user is gone
81*/
82_PUBLIC_ void arcfour_crypt(uint8_t *data, const uint8_t keystr[16], int len)
83{
84	DATA_BLOB key = data_blob(keystr, 16);
85
86	arcfour_crypt_blob(data, len, &key);
87
88	data_blob_free(&key);
89}
90
91
92