SymmetricEncryption


1   /*
2    * Title:        Oyster Project
3    * Description:  S/MIME email sending capabilities
4    * @Author       Vladan Obradovic
5    * @Version      2.1.5
6    */
7   
8   
9   package  org.enhydra.oyster.crypto;
10  
11  import java.security.SecureRandom  ;
12  import java.security.Key  ;
13  import javax.crypto.SecretKey;
14  import javax.crypto.KeyGenerator;
15  import javax.crypto.Cipher;
16  import javax.crypto.spec.IvParameterSpec;
17  import javax.crypto.spec.SecretKeySpec;
18  import org.enhydra.oyster.exception.SMIMEException;
19  import org.enhydra.oyster.exception.ErrorStorage;
20  
21  
22  /**
23   * SymmetricEncryption class is used for symmetric encryption large amounts
24   * of data. Algorithm names and corresponding key lengths are:<BR>
25   * DES - 56<BR>
26   * DES_EDE3_CBC - 128, 192<BR>
27   * RC2_CBC - 40, 64, 128<BR>
28   */
29  public class SymmetricEncryption {
30  
31  /**
32   * Storage for initialization vector (iv).
33   */
34    private byte[] iv = null;
35  
36  /**
37   * Storage for symmetric key.
38   */
39    private byte[] symmetricKey = null;
40  
41  /**
42   * Storage for symetric key length.
43   */
44    private int symmetricKeyLength = 0;
45  
46  /**
47   * Storage for symetric algorithm name.
48   */
49    private String   algorithmName = null;
50  
51  /**
52   * Container for encrypted message.
53   */
54    private byte[] encryptedValue = null;
55  
56  /**
57   * Container for decrypted message.
58   */
59    private byte[] decryptedValue = null;
60  
61  /**
62   * Construction with the given algorithm name and key size in bits.
63   * @param algorithmName0 is name of algorithm: "DES", "DES_EDE3_CBC" or "RC2_CBC".
64   * @param keyLength0 is key size in bits.
65   * @exception SMIMEException thrown in case of invalid algorithm names, or in
66   * case of wrong key sizes in bits.
67   */
68    public SymmetricEncryption (String   algorithmName0, int keyLength0) throws SMIMEException
69    {
70      AlgorithmChecker alg = new AlgorithmChecker(algorithmName0, keyLength0);
71      symmetricKeyLength = alg.getKeySize();
72      algorithmName = alg.getAlgorithmName();
73    }
74  
75  /**
76   * Encryption of the byte array with random generated key
77   * @param forEncrypt0 is byte array for encryption
78   * @exception SMIMEException caused by non SMIMEException which can be one of
79   * the following: NoSuchPaddingException, NoSuchProviderException,
80   * NoSuchAlgorithmException, InvalidKeyException, BadPaddingException,
81   * IllegalBlockSizeException.
82   */
83    public void encrypt (byte[] forEncrypt0) throws SMIMEException {
84      try {
85        SecureRandom   rand = SecureRandom.getInstance("SHA1PRNG", "SUN");
86        KeyGenerator keyGen = KeyGenerator.getInstance(algorithmName, "BC");      // Construct key and cipher for Symmetric Cipher and choosed algorithm
87        keyGen.init(symmetricKeyLength);
88        Key   key = keyGen.generateKey();
89        Cipher cipher = Cipher.getInstance(algorithmName + "/CBC/PKCS5Padding", "BC");
90        cipher.init(Cipher.ENCRYPT_MODE, key, rand);
91        iv = cipher.getIV();
92        symmetricKey = key.getEncoded();
93        encryptedValue = cipher.doFinal(forEncrypt0);
94      }
95      catch(Exception   e) {
96        throw SMIMEException.getInstance(this, e, "encryption" );
97      }
98    }
99  
100 /**
101  * Encryption of the byte array with the given symmetric key
102  * @param forEncrypt0 is byte array for encryption
103  * @param simKey0 symmetric key
104  * @exception SMIMEException if number of bytes in imported symmetric Key is
105  * incorect. Also, can be caused by non SMIMEException  which can be one of the following:
106  * NoSuchPaddingException, NoSuchProviderException, NoSuchAlgorithmException,
107  * InvalidKeyException, BadPaddingException, IllegalBlockSizeException.
108  */
109   public void encrypt (byte[] forEncrypt0, byte[] simKey0) throws SMIMEException{
110     try {
111       if (simKey0.length != symmetricKeyLength)
112         throw  new SMIMEException(this, 1011);
113       SecureRandom   rand = SecureRandom.getInstance("SHA1PRNG", "SUN");
114       SecretKeySpec secSpec = new SecretKeySpec(simKey0, algorithmName);
115       Cipher cipher = Cipher.getInstance(algorithmName + "/CBC/PKCS5Padding", "BC");
116       cipher.init(Cipher.ENCRYPT_MODE, (SecretKey)secSpec, rand);
117       iv = cipher.getIV();
118       symmetricKey = simKey0;
119       encryptedValue = cipher.doFinal(forEncrypt0);
120     }
121     catch(Exception   e) {
122       throw SMIMEException.getInstance(this, e, "encryption" );
123     }
124   }
125 
126 /**
127  * Returns the algorithm name used for symmetric encryption.
128  * @return Name of the chosen algorithm for symmetric encryption.
129  */
130   public String   getAlgorithmName () {
131     return  algorithmName;
132   }
133 
134 /**
135  * Returns the key size in bits used for chosen algorithm name.
136  * @return Key size in bits for the chosen algorithm for symmetric
137  * encryption.
138  */
139   public int getKeyLength () {
140     return  symmetricKeyLength;
141   }
142 
143 /**
144  * Returns the initialization vector (IV) used for Symmetric Cipher and
145  * the chosen algorithm.
146  * @return IV as a byte array.
147  */
148   public byte[] getIV () {
149     return  iv;
150   }
151 
152 /**
153  * Returns the generated symmetric key in bytes.
154  * @return Symmetric key in byte array.
155  */
156   public byte[] getSymmetricKey () {
157     return  symmetricKey;
158   }
159 
160 /**
161  * Returns the encrypted content.
162  * @return Encrypted content as byte array.
163  */
164   public byte[] getEncryptedValue () {
165     return  encryptedValue;
166   }
167 
168 /**
169  * Decription of the byte array with the symmetric key and IV previously
170  * generated by the process of encryption in the same session with the same
171  * object. This method is mainly used in testing purposes.
172  * @param forDecrypt previosly encrypted byte array
173  * @exception SMIMEException caused by non SMIMEException  which can be one of the following:
174  * NoSuchPaddingException, NoSuchProviderException, NoSuchAlgorithmException,
175  * InvalidKeyException, BadPaddingException, IllegalBlockSizeException.
176  */
177   public void decrypt (byte[] forDecrypt) throws SMIMEException {
178     try {
179       SecretKeySpec secSpec = new SecretKeySpec(symmetricKey, algorithmName);
180       Cipher symCipher = Cipher.getInstance(algorithmName + "/CBC/PKCS5Padding", "BC");
181       symCipher.init(Cipher.DECRYPT_MODE, (SecretKey)secSpec, new IvParameterSpec(iv));
182       decryptedValue = symCipher.doFinal(forDecrypt);
183     }
184     catch(Exception   e) {
185       throw SMIMEException.getInstance(this, e, "decryption" );
186     }
187   }
188 
189 /**
190  * Decription of the byte array with the given symmetric key and
191  * initialization vector (IV)
192  * @param forDecrypt byte array for encryption
193  * @param simKey0 imported symetric key
194  * @param iv0 imported initialization vector
195  * @exception SMIMEException if number of bytes in imported symmetric key is
196  * incorect, or if number of bytes in imported IV isn't 8. Also, can be caused
197  * by non SMIMEException which can be one of the following:
198  * NoSuchPaddingException, NoSuchProviderException, NoSuchAlgorithmException,
199  * InvalidKeyException, BadPaddingException, IllegalBlockSizeException.
200  */
201   public void decrypt (byte[] forDecrypt, byte[] simKey0, byte[] iv0) throws SMIMEException {
202     try {
203       if (simKey0.length*8 != symmetricKeyLength)
204         throw  new SMIMEException(this, 1011);
205       if (iv0.length != 8)
206         throw  new SMIMEException(this, 1012);
207       SecretKeySpec secSpec = new SecretKeySpec(simKey0, algorithmName);
208       Cipher symCipher = Cipher.getInstance(algorithmName + "/CBC/PKCS5Padding", "BC");
209       symCipher.init(Cipher.DECRYPT_MODE, (SecretKey)secSpec, new IvParameterSpec(iv0));
210       decryptedValue = symCipher.doFinal(forDecrypt);
211     }
212     catch(Exception   e) {
213       throw SMIMEException.getInstance(this, e, "decryption" );
214     }
215   }
216 
217 /**
218  * Returns the decrypted content
219  * @return Decrypted content as a byte array.
220  */
221   public byte[] getDecryptedValue () {
222     return  decryptedValue;
223   }
224 
225 /**
226  * Resets (sets to null) all private attributes in generated instance of
227  * the class.
228  */
229   public void reset () {
230     iv = null;
231     symmetricKey = null;
232     symmetricKeyLength = 0;
233     String   algorithmName = null;
234     encryptedValue = null;
235     decryptedValue = null;
236   }
237 }
238 
239 
240 
241
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