1 package org.ibex.crypto;
5 private static final byte[] encodingTable =
7 (byte)'A', (byte)'B', (byte)'C', (byte)'D', (byte)'E', (byte)'F', (byte)'G',
8 (byte)'H', (byte)'I', (byte)'J', (byte)'K', (byte)'L', (byte)'M', (byte)'N',
9 (byte)'O', (byte)'P', (byte)'Q', (byte)'R', (byte)'S', (byte)'T', (byte)'U',
10 (byte)'V', (byte)'W', (byte)'X', (byte)'Y', (byte)'Z',
11 (byte)'a', (byte)'b', (byte)'c', (byte)'d', (byte)'e', (byte)'f', (byte)'g',
12 (byte)'h', (byte)'i', (byte)'j', (byte)'k', (byte)'l', (byte)'m', (byte)'n',
13 (byte)'o', (byte)'p', (byte)'q', (byte)'r', (byte)'s', (byte)'t', (byte)'u',
15 (byte)'w', (byte)'x', (byte)'y', (byte)'z',
16 (byte)'0', (byte)'1', (byte)'2', (byte)'3', (byte)'4', (byte)'5', (byte)'6',
17 (byte)'7', (byte)'8', (byte)'9',
22 * encode the input data producong a base 64 encoded byte array.
24 * @return a byte array containing the base 64 encoded data.
26 public static byte[] encode(
31 int modulus = data.length % 3;
34 bytes = new byte[4 * data.length / 3];
38 bytes = new byte[4 * ((data.length / 3) + 1)];
41 int dataLength = (data.length - modulus);
43 for (int i = 0, j = 0; i < dataLength; i += 3, j += 4)
46 a2 = data[i + 1] & 0xff;
47 a3 = data[i + 2] & 0xff;
49 bytes[j] = encodingTable[(a1 >>> 2) & 0x3f];
50 bytes[j + 1] = encodingTable[((a1 << 4) | (a2 >>> 4)) & 0x3f];
51 bytes[j + 2] = encodingTable[((a2 << 2) | (a3 >>> 6)) & 0x3f];
52 bytes[j + 3] = encodingTable[a3 & 0x3f];
56 * process the tail end.
63 case 0: /* nothing left to do */
66 d1 = data[data.length - 1] & 0xff;
67 b1 = (d1 >>> 2) & 0x3f;
68 b2 = (d1 << 4) & 0x3f;
70 bytes[bytes.length - 4] = encodingTable[b1];
71 bytes[bytes.length - 3] = encodingTable[b2];
72 bytes[bytes.length - 2] = (byte)'=';
73 bytes[bytes.length - 1] = (byte)'=';
76 d1 = data[data.length - 2] & 0xff;
77 d2 = data[data.length - 1] & 0xff;
79 b1 = (d1 >>> 2) & 0x3f;
80 b2 = ((d1 << 4) | (d2 >>> 4)) & 0x3f;
81 b3 = (d2 << 2) & 0x3f;
83 bytes[bytes.length - 4] = encodingTable[b1];
84 bytes[bytes.length - 3] = encodingTable[b2];
85 bytes[bytes.length - 2] = encodingTable[b3];
86 bytes[bytes.length - 1] = (byte)'=';
94 * set up the decoding table.
96 private static final byte[] decodingTable;
100 decodingTable = new byte[128];
102 for (int i = 'A'; i <= 'Z'; i++)
104 decodingTable[i] = (byte)(i - 'A');
107 for (int i = 'a'; i <= 'z'; i++)
109 decodingTable[i] = (byte)(i - 'a' + 26);
112 for (int i = '0'; i <= '9'; i++)
114 decodingTable[i] = (byte)(i - '0' + 52);
117 decodingTable['+'] = 62;
118 decodingTable['/'] = 63;
122 * decode the base 64 encoded input data.
124 * @return a byte array representing the decoded data.
126 public static byte[] decode(
132 if (data[data.length - 2] == '=')
134 bytes = new byte[(((data.length / 4) - 1) * 3) + 1];
136 else if (data[data.length - 1] == '=')
138 bytes = new byte[(((data.length / 4) - 1) * 3) + 2];
142 bytes = new byte[((data.length / 4) * 3)];
145 for (int i = 0, j = 0; i < data.length - 4; i += 4, j += 3)
147 b1 = decodingTable[data[i]];
148 b2 = decodingTable[data[i + 1]];
149 b3 = decodingTable[data[i + 2]];
150 b4 = decodingTable[data[i + 3]];
152 bytes[j] = (byte)((b1 << 2) | (b2 >> 4));
153 bytes[j + 1] = (byte)((b2 << 4) | (b3 >> 2));
154 bytes[j + 2] = (byte)((b3 << 6) | b4);
157 if (data[data.length - 2] == '=')
159 b1 = decodingTable[data[data.length - 4]];
160 b2 = decodingTable[data[data.length - 3]];
162 bytes[bytes.length - 1] = (byte)((b1 << 2) | (b2 >> 4));
164 else if (data[data.length - 1] == '=')
166 b1 = decodingTable[data[data.length - 4]];
167 b2 = decodingTable[data[data.length - 3]];
168 b3 = decodingTable[data[data.length - 2]];
170 bytes[bytes.length - 2] = (byte)((b1 << 2) | (b2 >> 4));
171 bytes[bytes.length - 1] = (byte)((b2 << 4) | (b3 >> 2));
175 b1 = decodingTable[data[data.length - 4]];
176 b2 = decodingTable[data[data.length - 3]];
177 b3 = decodingTable[data[data.length - 2]];
178 b4 = decodingTable[data[data.length - 1]];
180 bytes[bytes.length - 3] = (byte)((b1 << 2) | (b2 >> 4));
181 bytes[bytes.length - 2] = (byte)((b2 << 4) | (b3 >> 2));
182 bytes[bytes.length - 1] = (byte)((b3 << 6) | b4);
189 * decode the base 64 encoded String data.
191 * @return a byte array representing the decoded data.
193 public static byte[] decode(
199 if (data.charAt(data.length() - 2) == '=')
201 bytes = new byte[(((data.length() / 4) - 1) * 3) + 1];
203 else if (data.charAt(data.length() - 1) == '=')
205 bytes = new byte[(((data.length() / 4) - 1) * 3) + 2];
209 bytes = new byte[((data.length() / 4) * 3)];
212 for (int i = 0, j = 0; i < data.length() - 4; i += 4, j += 3)
214 b1 = decodingTable[data.charAt(i)];
215 b2 = decodingTable[data.charAt(i + 1)];
216 b3 = decodingTable[data.charAt(i + 2)];
217 b4 = decodingTable[data.charAt(i + 3)];
219 bytes[j] = (byte)((b1 << 2) | (b2 >> 4));
220 bytes[j + 1] = (byte)((b2 << 4) | (b3 >> 2));
221 bytes[j + 2] = (byte)((b3 << 6) | b4);
224 if (data.charAt(data.length() - 2) == '=')
226 b1 = decodingTable[data.charAt(data.length() - 4)];
227 b2 = decodingTable[data.charAt(data.length() - 3)];
229 bytes[bytes.length - 1] = (byte)((b1 << 2) | (b2 >> 4));
231 else if (data.charAt(data.length() - 1) == '=')
233 b1 = decodingTable[data.charAt(data.length() - 4)];
234 b2 = decodingTable[data.charAt(data.length() - 3)];
235 b3 = decodingTable[data.charAt(data.length() - 2)];
237 bytes[bytes.length - 2] = (byte)((b1 << 2) | (b2 >> 4));
238 bytes[bytes.length - 1] = (byte)((b2 << 4) | (b3 >> 2));
242 b1 = decodingTable[data.charAt(data.length() - 4)];
243 b2 = decodingTable[data.charAt(data.length() - 3)];
244 b3 = decodingTable[data.charAt(data.length() - 2)];
245 b4 = decodingTable[data.charAt(data.length() - 1)];
247 bytes[bytes.length - 3] = (byte)((b1 << 2) | (b2 >> 4));
248 bytes[bytes.length - 2] = (byte)((b2 << 4) | (b3 >> 2));
249 bytes[bytes.length - 1] = (byte)((b3 << 6) | b4);