https://katalog.knihovna-vratimov.cz/themes/bootstrap3/js/vendor/rc4.js?_=1461344400

1/* RC4 symmetric cipher encryption/decryption
2 * Copyright (c) 2006 by Ali Farhadi.
3 * released under the terms of the Gnu Public License.
4 * see the GPL for details.
5 *
6 * Email: ali[at]farhadi[dot]ir
7 * Website: http://farhadi.ir/
8 */
9
10/**
11 * Encrypt given plain text using the key with RC4 algorithm.
12 * All parameters and return value are in binary format.
13 *
14 * @param string key - secret key for encryption
15 * @param string pt - plain text to be encrypted
16 * @return string
17 */
18function rc4Encrypt(key, pt) {
19  s = new Array();
20  for (var i=0; i<256; i++) {
21    s[i] = i;
22  }
23  var j = 0;
24  var x;
25  for (i=0; i<256; i++) {
26    j = (j + s[i] + key.charCodeAt(i % key.length)) % 256;
27    x = s[i];
28    s[i] = s[j];
29    s[j] = x;
30  }
31  i = 0;
32  j = 0;
33  var ct = '';
34  for (var y=0; y<pt.length; y++) {
35    i = (i + 1) % 256;
36    j = (j + s[i]) % 256;
37    x = s[i];
38    s[i] = s[j];
39    s[j] = x;
40    ct += String.fromCharCode(pt.charCodeAt(y) ^ s[(s[i] + s[j]) % 256]);
41  }
42  return ct;
43}
44
45/**
46 * Decrypt given cipher text using the key with RC4 algorithm.
47 * All parameters and return value are in binary format.
48 *
49 * @param string key - secret key for decryption
50 * @param string ct - cipher text to be decrypted
51 * @return string
52*/
53function rc4Decrypt(key, ct) {
54  return rc4Encrypt(key, ct);
55}
56
57/* Hexadecimal conversion methods.
58 * Copyright (c) 2006 by Ali Farhadi.
59 * released under the terms of the Gnu Public License.
60 * see the GPL for details.
61 *
62 * Email: ali[at]farhadi[dot]ir
63 * Website: http://farhadi.ir/
64 */
65
66//Encodes data to Hex(base16) format
67function hexEncode(data){
68  var b16_digits = '0123456789abcdef';
69  var b16_map = new Array();
70  for (var i=0; i<256; i++) {
71    b16_map[i] = b16_digits.charAt(i >> 4) + b16_digits.charAt(i & 15);
72  }
73
74  var result = new Array();
75  for (var i=0; i<data.length; i++) {
76    result[i] = b16_map[data.charCodeAt(i)];
77  }
78
79  return result.join('');
80}
81
82//Decodes Hex(base16) formated data
83function hexDecode(data){
84  var b16_digits = '0123456789abcdef';
85  var b16_map = new Array();
86  for (var i=0; i<256; i++) {
87    b16_map[b16_digits.charAt(i >> 4) + b16_digits.charAt(i & 15)] = String.fromCharCode(i);
88  }
89  if (!data.match(/^[a-f0-9]*$/i)) return false;// return false if input data is not a valid Hex string
90
91  if (data.length % 2) data = '0'+data;
92
93  var result = new Array();
94  var j=0;
95  for (var i=0; i<data.length; i+=2) {
96    result[j++] = b16_map[data.substr(i,2)];
97  }
98
99  return result.join('');
100}