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1 package com.openedit.users;
2
3 import java.io.UnsupportedEncodingException  ;
4 import java.security.InvalidKeyException ;
5 import java.security.NoSuchAlgorithmException ;
6 import java.security.spec.KeySpec ;
7
8 import javax.crypto.Cipher;
9 import javax.crypto.NoSuchPaddingException;
10 import javax.crypto.SecretKey;
11 import javax.crypto.SecretKeyFactory;
12 import javax.crypto.spec.DESKeySpec;
13 import javax.crypto.spec.DESedeKeySpec;
14
15 import org.apache.commons.codec.binary.Base64;
16
17 import com.openedit.OpenEditException;
18
19 public class StringEncrypter
20 {
21 public static final String DESEDE_ENCRYPTION_SCHEME = "DESede";
22 public static final String DES_ENCRYPTION_SCHEME = "DES";
23 public static final String DEFAULT_ENCRYPTION_KEY = "This is a fairly long phrase used to encrypt";
24
25 private KeySpec keySpec;
26 private SecretKeyFactory keyFactory;
27 private Cipher cipher;
28
29 private static final String UNICODE_FORMAT = "UTF8";
30
31 public StringEncrypter( String encryptionScheme ) throws OpenEditException
32 {
33 this( encryptionScheme, DEFAULT_ENCRYPTION_KEY );
34 }
35
36 public StringEncrypter( String encryptionScheme, String encryptionKey )
37 throws OpenEditException
38 {
39
40 if ( encryptionKey == null )
41 throw new IllegalArgumentException ( "encryption key was null" );
42 if ( encryptionKey.trim().length() < 24 )
43 throw new IllegalArgumentException (
44 "encryption key was less than 24 characters" );
45
46 try
47 {
48 byte[] keyAsBytes = encryptionKey.getBytes( UNICODE_FORMAT );
49
50 if ( encryptionScheme.equals( DESEDE_ENCRYPTION_SCHEME) )
51 {
52 keySpec = new DESedeKeySpec( keyAsBytes );
53 }
54 else if ( encryptionScheme.equals( DES_ENCRYPTION_SCHEME ) )
55 {
56 keySpec = new DESKeySpec( keyAsBytes );
57 }
58 else
59 {
60 throw new IllegalArgumentException ( "Encryption scheme not supported: "
61 + encryptionScheme );
62 }
63
64 keyFactory = SecretKeyFactory.getInstance( encryptionScheme );
65 cipher = Cipher.getInstance( encryptionScheme );
66
67 }
68 catch (InvalidKeyException e)
69 {
70 throw new OpenEditException( e );
71 }
72 catch (UnsupportedEncodingException e)
73 {
74 throw new OpenEditException( e );
75 }
76 catch (NoSuchAlgorithmException e)
77 {
78 throw new OpenEditException( e );
79 }
80 catch (NoSuchPaddingException e)
81 {
82 throw new OpenEditException( e );
83 }
84
85 }
86
87 public String encrypt( String unencryptedString ) throws OpenEditException
88 {
89 if ( unencryptedString == null || unencryptedString.trim().length() == 0 )
90 throw new IllegalArgumentException (
91 "unencrypted string was null or empty" );
92
93 try
94 {
95 SecretKey key = keyFactory.generateSecret( keySpec );
96 cipher.init( Cipher.ENCRYPT_MODE, key );
97 byte[] cleartext = unencryptedString.getBytes( UNICODE_FORMAT );
98 byte[] ciphertext = cipher.doFinal( cleartext );
99
100 Base64 base64encoder = new Base64();
101 return new String ( base64encoder.encode( ciphertext ), UNICODE_FORMAT );
102 }
103 catch (Exception e)
104 {
105 throw new OpenEditException( e );
106 }
107 }
108
109 public String decrypt( String encryptedString ) throws OpenEditException
110 {
111 if ( encryptedString == null || encryptedString.trim().length() <= 0 )
112 throw new IllegalArgumentException ( "encrypted string was null or empty" );
113
114 try
115 {
116 SecretKey key = keyFactory.generateSecret( keySpec );
117 cipher.init( Cipher.DECRYPT_MODE, key );
118 Base64 base64decoder = new Base64();
119 byte[] cleartext = base64decoder.decode( encryptedString.getBytes( UNICODE_FORMAT ) );
120 byte[] ciphertext = cipher.doFinal( cleartext );
121
122 return bytes2String( ciphertext );
123 }
124 catch (Exception e)
125 {
126 throw new OpenEditException( e );
127 }
128 }
129
130 private static String bytes2String( byte[] bytes )
131 {
132 StringBuffer stringBuffer = new StringBuffer ();
133 for (int i = 0; i < bytes.length; i++)
134 {
135 stringBuffer.append( (char) bytes[i] );
136 }
137 return stringBuffer.toString();
138 }
139
140 } |
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