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comparison src/com/trilead/ssh2/crypto/KeyMaterial.java @ 0:0ce5cc452d02

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initial version
author Carl Byington <carl@five-ten-sg.com>
date Thu, 22 May 2014 10:41:19 -0700
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-1:000000000000 0:0ce5cc452d02
1
2 package com.trilead.ssh2.crypto;
3
4
5 import java.math.BigInteger;
6
7 import com.trilead.ssh2.crypto.digest.HashForSSH2Types;
8
9 /**
10 * Establishes key material for iv/key/mac (both directions).
11 *
12 * @author Christian Plattner, plattner@trilead.com
13 * @version $Id: KeyMaterial.java,v 1.1 2007/10/15 12:49:56 cplattne Exp $
14 */
15 public class KeyMaterial {
16 public byte[] initial_iv_client_to_server;
17 public byte[] initial_iv_server_to_client;
18 public byte[] enc_key_client_to_server;
19 public byte[] enc_key_server_to_client;
20 public byte[] integrity_key_client_to_server;
21 public byte[] integrity_key_server_to_client;
22
23 private static byte[] calculateKey(HashForSSH2Types sh, BigInteger K, byte[] H, byte type, byte[] SessionID,
24 int keyLength) {
25 byte[] res = new byte[keyLength];
26 int dglen = sh.getDigestLength();
27 int numRounds = (keyLength + dglen - 1) / dglen;
28 byte[][] tmp = new byte[numRounds][];
29 sh.reset();
30 sh.updateBigInt(K);
31 sh.updateBytes(H);
32 sh.updateByte(type);
33 sh.updateBytes(SessionID);
34 tmp[0] = sh.getDigest();
35 int off = 0;
36 int produced = Math.min(dglen, keyLength);
37 System.arraycopy(tmp[0], 0, res, off, produced);
38 keyLength -= produced;
39 off += produced;
40
41 for (int i = 1; i < numRounds; i++) {
42 sh.updateBigInt(K);
43 sh.updateBytes(H);
44
45 for (int j = 0; j < i; j++)
46 sh.updateBytes(tmp[j]);
47
48 tmp[i] = sh.getDigest();
49 produced = Math.min(dglen, keyLength);
50 System.arraycopy(tmp[i], 0, res, off, produced);
51 keyLength -= produced;
52 off += produced;
53 }
54
55 return res;
56 }
57
58 public static KeyMaterial create(String hashAlgo, byte[] H, BigInteger K, byte[] SessionID, int keyLengthCS,
59 int blockSizeCS, int macLengthCS, int keyLengthSC, int blockSizeSC, int macLengthSC)
60 throws IllegalArgumentException {
61 KeyMaterial km = new KeyMaterial();
62 HashForSSH2Types sh = new HashForSSH2Types(hashAlgo);
63 km.initial_iv_client_to_server = calculateKey(sh, K, H, (byte) 'A', SessionID, blockSizeCS);
64 km.initial_iv_server_to_client = calculateKey(sh, K, H, (byte) 'B', SessionID, blockSizeSC);
65 km.enc_key_client_to_server = calculateKey(sh, K, H, (byte) 'C', SessionID, keyLengthCS);
66 km.enc_key_server_to_client = calculateKey(sh, K, H, (byte) 'D', SessionID, keyLengthSC);
67 km.integrity_key_client_to_server = calculateKey(sh, K, H, (byte) 'E', SessionID, macLengthCS);
68 km.integrity_key_server_to_client = calculateKey(sh, K, H, (byte) 'F', SessionID, macLengthSC);
69 return km;
70 }
71 }