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1 package com.quikj.server.framework;
2
3 import lava.security.des.*;
4 import java.util.*;
5
6
11 public final class DESEncryption
12 {
13 private static final String  PAD8 = " ";
14
15
18 public DESEncryption()
19 {
20 }
21
27 public static String byteToString(byte[] inp)
28 {
29 StringBuffer buffer = new StringBuffer ();
30 for (int i = 0; i < inp.length; i++)
31 {
32 String n = Byte.toString(inp[i]);
33 int len = n.length();
34
35 if (len == 1)
36 {
37 buffer.append("$$$" + n);
38 }
39 else if (len == 2)
40 {
41 buffer.append("$$" + n);
42 }
43 else if (len == 3)
44 {
45 buffer.append("$" + n);
46 }
47 else
48 {
49 buffer.append(n);
50 }
51 }
52
53 return buffer.toString();
54
55 }
56
62 public String decode(String text, String secret)
63 {
64 try
65 {
66 byte[] input = stringToByte(text);
67 if (input == null)
68 {
69 return null;
70 }
71
72 byte[] output = new byte[input.length];
73
74 DesKey des_key = new DesKey(secret.getBytes(), 0);
75 DesEngine engine = new DesEngine(des_key);
76
77 engine.decrypt(input, output, input.length);
78 return new String (output);
79 }
80 catch (Exception ex)
81 {
82 return null;
83 }
84 }
85
91 public String encode(String text, String secret)
92 {
93 try
94 {
95 int pad_length = 8 - (text.length() % 8);
96
97 String padded_text = text + PAD8.substring(0, pad_length);
98 byte[] input = padded_text.getBytes();
99
100 byte[] output = new byte[input.length];
101
102 DesKey des_key = new DesKey(secret.getBytes(), 0);
103 DesEngine engine = new DesEngine(des_key);
104
105 engine.encrypt(input, output, text.length());
106 return byteToString(output);
107 }
108 catch (Exception ex)
109 {
110 return null;
111 }
112 }
113
118 public static void main(String [] args)
119 {
120 try
121 {
122 if (args.length < 3)
123 {
124 System.err.println("Usage <-e/-d> text secret");
125 System.exit(1);
126 }
127
128 DESEncryption enc = new DESEncryption();
129 if (args[0].equals("-e") == true)
130 {
131 System.out.println("Result: " + enc.encrypt(args[1], args[2]));
132
133 }
134 else if (args[0].equals("-d") == true)
135 {
136 System.out.println("Result: --" + enc.decrypt(args[1], args[2])
137 +"--");
138 }
139 else
140 {
141 System.err.println("Unknown option " + args[0]);
142 System.exit(2);
143 }
144 }
145 catch (Exception ex)
146 {
147 System.err.println(ex.getClass().getName() + ": " + ex.getMessage());
148 System.exit(3);
149 }
150
151 System.exit(0);
152 }
153
159 public static byte[] stringToByte(String text)
160 {
161 int len = text.length();
162 if ((len % 4) > 0)
163 {
164 return null;
165 }
166
167 byte[] input = new byte[len / 4];
168 for (int i = 0; i < len; i += 4)
169 {
170 String element = text.substring(i, i + 4);
171
172 if (element.startsWith("$$$") == true)
173 {
174 element = element.substring(3);
175 }
176 else if (element.startsWith("$$") == true)
177 {
178 element = element.substring(2);
179 }
180 else if (element.startsWith("$") == true)
181 {
182 element = element.substring(1);
183 }
184
185 try
186 {
187 input[i / 4] = Byte.parseByte(element);
188 }
189 catch (NumberFormatException ex)
190 {
191 return null;
192 }
193 }
194 return input;
195 }
196
197 public String encrypt(String text, String secret)
198 {
199 return text.length() + ":" + encode(text, secret);
200 }
201
202 public String decrypt(String text, String secret)
203 {
204 StringTokenizer tokens = new StringTokenizer(text, ":");
205 int num_tokens = tokens.countTokens();
206
207 if (num_tokens < 2)
208 {
209 return null;
210 }
211
212 String size_s = tokens.nextToken();
213 int size = 0;
214 try
215 {
216 size = Integer.parseInt(size_s);
217 }
218 catch (NumberFormatException ex)
219 {
220 return null;
221 }
222
223 String encrypted_message = text.substring(size_s.length() + 1);
224 String decrypted_str = decode(encrypted_message, secret);
225 if (decrypted_str == null)
226 {
227 return null;
228 }
229
230 return decrypted_str.substring(0, size);
231 }
232 }
233 |
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