1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
|
/*
* Copyright (c) 2020-2023, yzrh <yzrh@noema.org>
*
* SPDX-License-Identifier: Apache-2.0
*/
#include "cnki.h"
int
cnki_kdh(cnki_t **param)
{
if (*param == NULL)
return 1;
if ((*param)->stat > 0)
printf("Begin 'KDH' decryption\n");
long cur = ADDRESS_KDH_BODY;
long end;
fseek((*param)->fp_i, 0, SEEK_END);
end = ftell((*param)->fp_i);
fseek((*param)->fp_i, cur, SEEK_SET);
const char key[] = KEY_KDH;
const int key_len = KEY_KDH_LENGTH;
long key_cur = 0;
int buf_size;
char buf[(*param)->size_buf];
FILE *tmp = tmpfile();
if (tmp == NULL)
return 1;
for (;;) {
if (cur + (*param)->size_buf < end)
buf_size = (*param)->size_buf;
else
buf_size = end - cur;
fread(buf, buf_size, 1, (*param)->fp_i);
for (int i = 0; i < buf_size; i++)
buf[i] ^= key[key_cur++ % key_len];
fwrite(buf, buf_size, 1, tmp);
if ((cur = ftell((*param)->fp_i)) >= end)
break;
}
if ((*param)->stat > 0)
printf("Decrypted %ld byte(s)\n", ftell(tmp));
fclose((*param)->fp_i);
fseek(tmp, 0, SEEK_SET);
(*param)->fp_i = tmp;
cnki_pdf(param);
if ((*param)->stat > 0)
printf("Conversion ended\n");
return 0;
}
|
