1 /* 2 * Copyright (c) 2006-2011 Christian Plattner. All rights reserved. 3 * Please refer to the LICENSE.txt for licensing details. 4 */ 5 package ch.ethz.ssh2.crypto.digest; 6 7 /** 8 * MAC. 9 * 10 * @author Christian Plattner 11 * @version 2.50, 03/15/10 12 */ 13 public final class MAC 14 { 15 Digest mac; 16 int size; 17 getMacList()18 public static String[] getMacList() 19 { 20 /* Higher Priority First */ 21 22 return new String[]{"hmac-sha1-96", "hmac-sha1", "hmac-md5-96", "hmac-md5"}; 23 } 24 checkMacList(String[] macs)25 public static void checkMacList(String[] macs) 26 { 27 for (int i = 0; i < macs.length; i++) 28 getKeyLen(macs[i]); 29 } 30 getKeyLen(String type)31 public static int getKeyLen(String type) 32 { 33 if (type.equals("hmac-sha1")) 34 return 20; 35 if (type.equals("hmac-sha1-96")) 36 return 20; 37 if (type.equals("hmac-md5")) 38 return 16; 39 if (type.equals("hmac-md5-96")) 40 return 16; 41 throw new IllegalArgumentException("Unkown algorithm " + type); 42 } 43 MAC(String type, byte[] key)44 public MAC(String type, byte[] key) 45 { 46 if (type.equals("hmac-sha1")) 47 { 48 mac = new HMAC(new SHA1(), key, 20); 49 } 50 else if (type.equals("hmac-sha1-96")) 51 { 52 mac = new HMAC(new SHA1(), key, 12); 53 } 54 else if (type.equals("hmac-md5")) 55 { 56 mac = new HMAC(new MD5(), key, 16); 57 } 58 else if (type.equals("hmac-md5-96")) 59 { 60 mac = new HMAC(new MD5(), key, 12); 61 } 62 else 63 throw new IllegalArgumentException("Unkown algorithm " + type); 64 65 size = mac.getDigestLength(); 66 } 67 initMac(int seq)68 public void initMac(int seq) 69 { 70 mac.reset(); 71 mac.update((byte) (seq >> 24)); 72 mac.update((byte) (seq >> 16)); 73 mac.update((byte) (seq >> 8)); 74 mac.update((byte) (seq)); 75 } 76 update(byte[] packetdata, int off, int len)77 public void update(byte[] packetdata, int off, int len) 78 { 79 mac.update(packetdata, off, len); 80 } 81 getMac(byte[] out, int off)82 public void getMac(byte[] out, int off) 83 { 84 mac.digest(out, off); 85 } 86 size()87 public int size() 88 { 89 return size; 90 } 91 } 92