annotate src/com/trilead/ssh2/crypto/cipher/CBCMode.java @ 285:486df527ddc5 ganymed

start conversion from trilead to ganymed
author Carl Byington <carl@five-ten-sg.com>
date Fri, 18 Jul 2014 18:33:40 -0700
parents 0ce5cc452d02
children
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
rev   line source
0
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
1 package com.trilead.ssh2.crypto.cipher;
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
2
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
3 /**
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
4 * CBCMode.
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
5 *
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
6 * @author Christian Plattner, plattner@trilead.com
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
7 * @version $Id: CBCMode.java,v 1.1 2007/10/15 12:49:55 cplattne Exp $
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
8 */
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
9 public class CBCMode implements BlockCipher {
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
10 BlockCipher tc;
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
11 int blockSize;
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
12 boolean doEncrypt;
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
13
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
14 byte[] cbc_vector;
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
15 byte[] tmp_vector;
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
16
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
17 public void init(boolean forEncryption, byte[] key) {
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
18 }
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
19
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
20 public CBCMode(BlockCipher tc, byte[] iv, boolean doEncrypt)
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
21 throws IllegalArgumentException {
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
22 this.tc = tc;
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
23 this.blockSize = tc.getBlockSize();
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
24 this.doEncrypt = doEncrypt;
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
25
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
26 if (this.blockSize != iv.length)
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
27 throw new IllegalArgumentException("IV must be " + blockSize
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
28 + " bytes long! (currently " + iv.length + ")");
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
29
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
30 this.cbc_vector = new byte[blockSize];
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
31 this.tmp_vector = new byte[blockSize];
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
32 System.arraycopy(iv, 0, cbc_vector, 0, blockSize);
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
33 }
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
34
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
35 public int getBlockSize() {
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
36 return blockSize;
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
37 }
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
38
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
39 private void encryptBlock(byte[] src, int srcoff, byte[] dst, int dstoff) {
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
40 for (int i = 0; i < blockSize; i++)
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
41 cbc_vector[i] ^= src[srcoff + i];
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
42
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
43 tc.transformBlock(cbc_vector, 0, dst, dstoff);
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
44 System.arraycopy(dst, dstoff, cbc_vector, 0, blockSize);
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
45 }
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
46
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
47 private void decryptBlock(byte[] src, int srcoff, byte[] dst, int dstoff) {
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
48 /* Assume the worst, src and dst are overlapping... */
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
49 System.arraycopy(src, srcoff, tmp_vector, 0, blockSize);
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
50 tc.transformBlock(src, srcoff, dst, dstoff);
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
51
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
52 for (int i = 0; i < blockSize; i++)
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
53 dst[dstoff + i] ^= cbc_vector[i];
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
54
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
55 /* ...that is why we need a tmp buffer. */
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
56 byte[] swap = cbc_vector;
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
57 cbc_vector = tmp_vector;
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
58 tmp_vector = swap;
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
59 }
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
60
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
61 public void transformBlock(byte[] src, int srcoff, byte[] dst, int dstoff) {
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
62 if (doEncrypt)
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
63 encryptBlock(src, srcoff, dst, dstoff);
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
64 else
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
65 decryptBlock(src, srcoff, dst, dstoff);
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
66 }
0ce5cc452d02 initial version
Carl Byington <carl@five-ten-sg.com>
parents:
diff changeset
67 }