01: /*
02: * Copyright (c) 2007, intarsys consulting GmbH
03: *
04: * Redistribution and use in source and binary forms, with or without
05: * modification, are permitted provided that the following conditions are met:
06: *
07: * - Redistributions of source code must retain the above copyright notice,
08: * this list of conditions and the following disclaimer.
09: *
10: * - Redistributions in binary form must reproduce the above copyright notice,
11: * this list of conditions and the following disclaimer in the documentation
12: * and/or other materials provided with the distribution.
13: *
14: * - Neither the name of intarsys nor the names of its contributors may be used
15: * to endorse or promote products derived from this software without specific
16: * prior written permission.
17: *
18: * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
19: * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21: * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
22: * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
23: * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
24: * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
25: * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
26: * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
27: * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
28: * POSSIBILITY OF SUCH DAMAGE.
29: */
30: package de.intarsys.pdf.crypt;
31:
32: import java.security.MessageDigest;
33: import java.security.NoSuchAlgorithmException;
34:
35: import javax.crypto.Cipher;
36: import javax.crypto.NoSuchPaddingException;
37: import javax.crypto.SecretKey;
38: import javax.crypto.spec.SecretKeySpec;
39:
40: /**
41: * An {@link ICryptHandler} implementing the RC4 algorithm.
42: *
43: */
44: public class ArcFourCryptHandler extends StandardCryptHandler {
45:
46: public static final String CIPHER_ALGORITHM = "RC4"; //$NON-NLS-1$
47:
48: public static final String KEY_ALGORITHM = "RC4"; //$NON-NLS-1$
49:
50: public static final String DIGEST_ALGORITHM = "MD5"; //$NON-NLS-1$
51:
52: public void init(byte[] pCryptKey) throws COSSecurityException {
53: super .init(pCryptKey);
54: try {
55: md = MessageDigest.getInstance(DIGEST_ALGORITHM);
56: cipher = Cipher.getInstance(CIPHER_ALGORITHM);
57: } catch (NoSuchAlgorithmException e) {
58: throw new COSSecurityException(e);
59: } catch (NoSuchPaddingException e) {
60: throw new COSSecurityException(e);
61: }
62: }
63:
64: synchronized protected byte[] basicDecrypt(byte[] data,
65: byte[] encryptionKey, int objectNum, int genNum)
66: throws COSSecurityException {
67: try {
68: updateHash(encryptionKey, objectNum, genNum);
69: byte[] keyBase = md.digest();
70: SecretKey skeySpec = new SecretKeySpec(keyBase, 0, length,
71: KEY_ALGORITHM);
72: cipher.init(Cipher.DECRYPT_MODE, skeySpec);
73: return cipher.doFinal(data);
74: } catch (Exception e) {
75: throw new COSSecurityException(e);
76: }
77: }
78:
79: synchronized protected byte[] basicEncrypt(byte[] data,
80: byte[] encryptionKey, int objectNum, int genNum)
81: throws COSSecurityException {
82: try {
83: updateHash(encryptionKey, objectNum, genNum);
84: byte[] keyBase = md.digest();
85: SecretKey skeySpec = new SecretKeySpec(keyBase, 0, length,
86: CIPHER_ALGORITHM);
87: cipher.init(Cipher.DECRYPT_MODE, skeySpec);
88: return cipher.doFinal(data);
89: } catch (Exception e) {
90: throw new COSSecurityException(e);
91: }
92: }
93:
94: }
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