CryptUtils: multi-thread check

diff --git a/src/be/nikiroo/utils/CryptUtils.java b/src/be/nikiroo/utils/CryptUtils.java
index 681692a00e6323531b1dae680bf5d0b774c8190a..ed6f9e08a04cb623823863e5ded858ad6b6d9748 100644 (file)
--- a/src/be/nikiroo/utils/CryptUtils.java
+++ b/src/be/nikiroo/utils/CryptUtils.java
@@ -20,16 +20,25 @@ import javax.net.ssl.SSLException;
 /**
  * Small utility class to do AES encryption/decryption.
  * <p>
+ * For the moment, it is multi-thread compatible, but beware:
+ * <ul>
+ * <li>The encrypt/decrypt calls are serialized</li>
+ * <li>The streams are independent and thus parallel</li>
+ * </ul>
+ * <p>
  * Do not assume it is actually secure until you checked the code...
  * 
  * @author niki
  */
 public class CryptUtils {
+       static private final String AES_NAME = "AES/ECB/PKCS5Padding";
+       
        private Cipher ecipher;
        private Cipher dcipher;
+       private SecretKey key;
 
        /**
-        * Small and leazy way to initialize a 128 bits key with {@link CryptUtils}.
+        * Small and lazy-easy way to initialize a 128 bits key with {@link CryptUtils}.
         * <p>
         * <b>Some</b> part of the key will be used to generate a 128 bits key and
         * initialize the {@link CryptUtils}; even NULL will generate something.
@@ -42,11 +51,7 @@ public class CryptUtils {
         */
        public CryptUtils(String key) {
                try {
-                       byte[] bytes32 = key2key(key);
-                       init(bytes32);
-                       for (int i = 0 ; i < bytes32.length ; i++) {
-                               bytes32[i] = 0;
-                       }
+                       init(key2key(key));
                } catch (InvalidKeyException e) {
                        // We made sure that the key is correct, so nothing here
                        e.printStackTrace();
@@ -66,9 +71,6 @@ public class CryptUtils {
         */
        public CryptUtils(byte[] bytes32) throws InvalidKeyException {
                init(bytes32);
-               for (int i = 0 ; i < bytes32.length ; i++) {
-                       bytes32[i] = 0;
-               }
        }
 
        /**
@@ -80,6 +82,7 @@ public class CryptUtils {
         * @return the auto-encode {@link InputStream}
         */
        public InputStream encryptInputStream(InputStream in) {
+               Cipher ecipher = newCipher(Cipher.ENCRYPT_MODE);
                return new CipherInputStream(in, ecipher);
        }
 
@@ -92,6 +95,7 @@ public class CryptUtils {
         * @return the auto-encode {@link OutputStream}
         */
        public OutputStream encryptOutpuStream(OutputStream out) {
+               Cipher ecipher = newCipher(Cipher.ENCRYPT_MODE);
                return new CipherOutputStream(out, ecipher);
        }
 
@@ -104,6 +108,7 @@ public class CryptUtils {
         * @return the auto-decode {@link InputStream}
         */
        public InputStream decryptInputStream(InputStream in) {
+               Cipher dcipher = newCipher(Cipher.DECRYPT_MODE);
                return new CipherInputStream(in, dcipher);
        }
 
@@ -116,6 +121,7 @@ public class CryptUtils {
         * @return the auto-decode {@link OutputStream}
         */
        public OutputStream decryptOutputStream(OutputStream out) {
+               Cipher dcipher = newCipher(Cipher.DECRYPT_MODE);
                return new CipherOutputStream(out, dcipher);
        }
 
@@ -136,12 +142,26 @@ public class CryptUtils {
                                                        + " bytes");
                }
 
-               SecretKey key = new SecretKeySpec(bytes32, "AES");
+               key = new SecretKeySpec(bytes32, "AES");
+               ecipher = newCipher(Cipher.ENCRYPT_MODE);
+               dcipher = newCipher(Cipher.DECRYPT_MODE);
+       }
+       
+       /**
+        * Create a new {@link Cipher}of the given mode (see
+        * {@link Cipher#ENCRYPT_MODE} and {@link Cipher#ENCRYPT_MODE}).
+        * 
+        * @param mode
+        *            the mode ({@link Cipher#ENCRYPT_MODE} or
+        *            {@link Cipher#ENCRYPT_MODE})
+        * 
+        * @return the new {@link Cipher}
+        */
+       private Cipher newCipher(int mode) {
                try {
-                       ecipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
-                       dcipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
-                       ecipher.init(Cipher.ENCRYPT_MODE, key);
-                       dcipher.init(Cipher.DECRYPT_MODE, key);
+                       Cipher cipher = Cipher.getInstance(AES_NAME);
+                       cipher.init(mode, key);
+                       return cipher;
                } catch (NoSuchAlgorithmException e) {
                        // Every implementation of the Java platform is required to support
                        // this standard Cipher transformation with 128 bits keys
@@ -155,6 +175,8 @@ public class CryptUtils {
                        // this standard Cipher transformation with 128 bits keys
                        e.printStackTrace();
                }
+               
+               return null;
        }
 
        /**
@@ -170,12 +192,14 @@ public class CryptUtils {
         *             it was)
         */
        public byte[] encrypt(byte[] data) throws SSLException {
-               try {
-                       return ecipher.doFinal(data);
-               } catch (IllegalBlockSizeException e) {
-                       throw new SSLException(e);
-               } catch (BadPaddingException e) {
-                       throw new SSLException(e);
+               synchronized (ecipher) {
+                       try {
+                               return ecipher.doFinal(data);
+                       } catch (IllegalBlockSizeException e) {
+                               throw new SSLException(e);
+                       } catch (BadPaddingException e) {
+                               throw new SSLException(e);
+                       }
                }
        }
 
@@ -265,12 +289,14 @@ public class CryptUtils {
         *             in case of I/O error
         */
        public byte[] decrypt(byte[] data) throws SSLException {
-               try {
-                       return dcipher.doFinal(data);
-               } catch (IllegalBlockSizeException e) {
-                       throw new SSLException(e);
-               } catch (BadPaddingException e) {
-                       throw new SSLException(e);
+               synchronized (dcipher) {
+                       try {
+                               return dcipher.doFinal(data);
+                       } catch (IllegalBlockSizeException e) {
+                               throw new SSLException(e);
+                       } catch (BadPaddingException e) {
+                               throw new SSLException(e);
+                       }
                }
        }