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
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
|
/* Copyright (C) 2022 Dinglan Peng
*
* This is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this software; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
* USA.
*/
package com.tigervnc.rdr;
import java.util.Arrays;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.InvalidAlgorithmParameterException;
import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import javax.crypto.BadPaddingException;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
public class AESEAXCipher {
private static final byte[] zeroBlock = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
private static final byte[] prefixBlock0 = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
private static final byte[] prefixBlock1 = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1};
private static final byte[] prefixBlock2 = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2};
private static final int[] lut = {0x0,0x87,0x0e,0x89};
public AESEAXCipher(byte[] key)
{
try {
Cipher blockCipher = Cipher.getInstance("AES");
cbcCipher = Cipher.getInstance("AES/CBC/NOPADDING");
ctrCipher = Cipher.getInstance("AES/CTR/NOPADDING");
keySpec = new SecretKeySpec(key, "AES");
blockCipher.init(Cipher.ENCRYPT_MODE, keySpec);
cbcCipher.init(Cipher.ENCRYPT_MODE, keySpec,
new IvParameterSpec(zeroBlock));
subKey1 = Arrays.copyOfRange(blockCipher.doFinal(zeroBlock), 0, 16);
subKey2 = new byte[16];
int v = (subKey1[0] & 0xff) >>> 6;
for (int i = 0; i < 15; i++) {
subKey2[i] = (byte)(((subKey1[i + 1] & 0xff) >>> 6) |
((subKey1[i] & 0xff) << 2));
subKey1[i] = (byte)(((subKey1[i + 1] & 0xff) >>> 7) |
((subKey1[i] & 0xff) << 1));
}
subKey2[14] ^= v >>> 1;
subKey2[15] = (byte)(((subKey1[15] & 0xff) << 2) ^ lut[v]);
subKey1[15] = (byte)(((subKey1[15] & 0xff) << 1) ^ lut[v >>> 1]);
} catch (NoSuchAlgorithmException | NoSuchPaddingException e) {
throw new Exception("AESEAXCipher: AES algorithm is not supported");
} catch (IllegalBlockSizeException | BadPaddingException |
InvalidKeyException | InvalidAlgorithmParameterException e) {
throw new Exception("AESEAXCipher: invalid key");
}
}
private void encryptCTR(byte[] input, int inputOffset, int inputLength,
byte[] output, int outputOffset, byte[] iv)
{
try {
ctrCipher.init(Cipher.ENCRYPT_MODE, keySpec, new IvParameterSpec(iv));
ctrCipher.doFinal(input, inputOffset, inputLength, output, outputOffset);
} catch (java.lang.Exception e) {
throw new Exception("AESEAXCipher: " + e.toString());
}
}
private byte[] computeCMAC(byte[] input, int offset,
int length, byte[] prefix)
{
int n = length / 16;
int m = (length + 15) / 16;
int r = length - n * 16;
byte[] cbcData = new byte[(m + 1) * 16];
System.arraycopy(prefix, 0, cbcData, 0, 16);
System.arraycopy(input, offset, cbcData, 16, length);
if (r == 0) {
for (int i = 0; i < 16; i++) {
cbcData[n * 16 + i] ^= subKey1[i] & 0xff;
}
} else {
cbcData[(n + 1) * 16 + r] = (byte)0x80;
for (int i = 0; i < 16; i++) {
cbcData[(n + 1) * 16 + i] ^= subKey2[i] & 0xff;
}
}
try {
byte[] encrypted = cbcCipher.doFinal(cbcData);
return Arrays.copyOfRange(encrypted, encrypted.length - 16, encrypted.length - 0);
} catch (java.lang.Exception e) {
throw new Exception("AESEAXCipher: " + e.getMessage());
}
}
public void encrypt(byte[] input, int inputOffset, int inputLength,
byte[] ad, int adOffset, int adLength,
byte[] nonce,
byte[] output, int outputOffset,
byte[] mac, int macOffset)
{
byte[] nCMAC = computeCMAC(nonce, 0, nonce.length, prefixBlock0);
encryptCTR(input, inputOffset, inputLength, output, outputOffset, nCMAC);
byte[] adCMAC = computeCMAC(ad, adOffset, adLength, prefixBlock1);
byte[] m = computeCMAC(output, outputOffset, inputLength, prefixBlock2);
for (int i = 0; i < 16; i++) {
mac[macOffset + i] = (byte)((m[i] & 0xff) ^
(nCMAC[i] & 0xff) ^
(adCMAC[i] & 0xff));
}
}
public void decrypt(byte[] input, int inputOffset, int inputLength,
byte[] ad, int adOffset, int adLength,
byte[] nonce,
byte[] output, int outputOffset,
byte[] mac, int macOffset)
{
byte[] nCMAC = computeCMAC(nonce, 0, nonce.length, prefixBlock0);
byte[] adCMAC = computeCMAC(ad, adOffset, adLength, prefixBlock1);
byte[] m = computeCMAC(input, inputOffset, inputLength, prefixBlock2);
for (int i = 0; i < 16; i++) {
byte x = (byte)((m[i] & 0xff) ^ (nCMAC[i] & 0xff) ^ (adCMAC[i] & 0xff));
if (x != mac[macOffset + i])
throw new Exception("AESEAXCipher: failed to authenticate message");
}
encryptCTR(input, inputOffset, inputLength, output, outputOffset, nCMAC);
}
private SecretKeySpec keySpec;
private Cipher ctrCipher;
private Cipher cbcCipher;
private byte[] subKey1;
private byte[] subKey2;
}
|
