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1
2 package ch.ethz.ssh2.crypto.digest;
3
4
10 public final class MAC
11 {
12 Digest mac;
13 int size;
14
15 public final static String  [] getMacList()
16 {
17
18
19 return new String [] { "hmac-sha1-96", "hmac-sha1", "hmac-md5-96", "hmac-md5" };
20 }
21
22 public final static void checkMacList(String [] macs)
23 {
24 for (int i = 0; i < macs.length; i++)
25 getKeyLen(macs[i]);
26 }
27
28 public final static int getKeyLen(String type)
29 {
30 if (type.equals("hmac-sha1"))
31 return 20;
32 if (type.equals("hmac-sha1-96"))
33 return 20;
34 if (type.equals("hmac-md5"))
35 return 16;
36 if (type.equals("hmac-md5-96"))
37 return 16;
38 throw new IllegalArgumentException ("Unkown algorithm " + type);
39 }
40
41 public MAC(String type, byte[] key)
42 {
43 if (type.equals("hmac-sha1"))
44 {
45 mac = new HMAC(new SHA1(), key, 20);
46 }
47 else if (type.equals("hmac-sha1-96"))
48 {
49 mac = new HMAC(new SHA1(), key, 12);
50 }
51 else if (type.equals("hmac-md5"))
52 {
53 mac = new HMAC(new MD5(), key, 16);
54 }
55 else if (type.equals("hmac-md5-96"))
56 {
57 mac = new HMAC(new MD5(), key, 12);
58 }
59 else
60 throw new IllegalArgumentException ("Unkown algorithm " + type);
61
62 size = mac.getDigestLength();
63 }
64
65 public final void initMac(int seq)
66 {
67 mac.reset();
68 mac.update((byte) (seq >> 24));
69 mac.update((byte) (seq >> 16));
70 mac.update((byte) (seq >> 8));
71 mac.update((byte) (seq));
72 }
73
74 public final void update(byte[] packetdata, int off, int len)
75 {
76 mac.update(packetdata, off, len);
77 }
78
79 public final void getMac(byte[] out, int off)
80 {
81 mac.digest(out, off);
82 }
83
84 public final int size()
85 {
86 return size;
87 }
88 }
89 |
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