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
|
/* Copyright (C) 2015-2017 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
*
* This is a specialized constant-time base64 implementation that resists side-channel attacks.
*/
package com.wireguard.crypto;
public class KeyEncoding {
public static final int WG_KEY_LEN = 32;
public static final int WG_KEY_LEN_BASE64 = 44;
private static void encodeBase64(char dest[], final int dest_offset, final byte src[], final int src_offset) {
final byte input[] = { (byte)((src[0 + src_offset] >>> 2) & 63),
(byte)(((src[0 + src_offset] << 4) | ((src[1 + src_offset] & 0xff) >>> 4)) & 63),
(byte)(((src[1 + src_offset] << 2) | ((src[2 + src_offset] & 0xff) >>> 6)) & 63),
(byte)(src[2 + src_offset] & 63) };
for (int i = 0; i < 4; ++i)
dest[i + dest_offset] = (char)(input[i] + 'A'
+ (((25 - input[i]) >>> 8) & 6)
- (((51 - input[i]) >>> 8) & 75)
- (((61 - input[i]) >>> 8) & 15)
+ (((62 - input[i]) >>> 8) & 3));
}
public static String keyToBase64(final byte key[]) {
if (key.length != WG_KEY_LEN)
throw new IllegalArgumentException("WireGuard keys must be 32 bytes");
final char base64[] = new char[WG_KEY_LEN_BASE64];
int i;
for (i = 0; i < WG_KEY_LEN / 3; ++i)
encodeBase64(base64, i * 4, key, i * 3);
final byte endSegment[] = { key[i * 3 + 0], key[i * 3 + 1], 0 };
encodeBase64(base64, i * 4, endSegment, 0);
base64[WG_KEY_LEN_BASE64 - 1] = '=';
return new String(base64);
}
private static int decodeBase64(final char src[], int src_offset) {
int val = 0;
for (int i = 0; i < 4; ++i)
val |= (-1
+ ((((('A' - 1) - src[i + src_offset]) & (src[i + src_offset] - ('Z' + 1))) >>> 8) & (src[i + src_offset] - 64))
+ ((((('a' - 1) - src[i + src_offset]) & (src[i + src_offset] - ('z' + 1))) >>> 8) & (src[i + src_offset] - 70))
+ ((((('0' - 1) - src[i + src_offset]) & (src[i + src_offset] - ('9' + 1))) >>> 8) & (src[i + src_offset] + 5))
+ ((((('+' - 1) - src[i + src_offset]) & (src[i + src_offset] - ('+' + 1))) >>> 8) & 63)
+ ((((('/' - 1) - src[i + src_offset]) & (src[i + src_offset] - ('/' + 1))) >>> 8) & 64)
) << (18 - 6 * i);
return val;
}
public static byte[] keyFromBase64(final String input) {
final char base64[] = input.toCharArray();
if (base64.length != WG_KEY_LEN_BASE64 || base64[WG_KEY_LEN_BASE64 - 1] != '=')
throw new IllegalArgumentException("WireGuard base64 keys must be 44 characters encoding 32 bytes");
final byte key[] = new byte[WG_KEY_LEN];
int i;
int val;
for (i = 0; i < WG_KEY_LEN / 3; ++i) {
val = decodeBase64(base64, i * 4);
if (val < 0)
throw new IllegalArgumentException("WireGuard base64 keys must be 44 characters encoding 32 bytes");
key[i * 3 + 0] = (byte)((val >>> 16) & 0xff);
key[i * 3 + 1] = (byte)((val >>> 8) & 0xff);
key[i * 3 + 2] = (byte)(val & 0xff);
}
final char endSegment[] = { base64[i * 4 + 0], base64[i * 4 + 1], base64[i * 4 + 2], 'A' };
val = decodeBase64(endSegment, 0);
if (val < 0 || (val & 0xff) != 0)
throw new IllegalArgumentException("WireGuard base64 keys must be 44 characters encoding 32 bytes");
key[i * 3 + 0] = (byte)((val >>> 16) & 0xff);
key[i * 3 + 1] = (byte)((val >>> 8) & 0xff);
return key;
}
}
|
