Re-implement hashing class

1 files changed, 70 insertions, 12 deletions

diff --git a/src/org/traccar/helper/Hashing.java b/src/org/traccar/helper/Hashing.java
index 3f3e30e6e..000821451 100644
--- a/src/org/traccar/helper/Hashing.java
+++ b/src/org/traccar/helper/Hashing.java
@@ -1,21 +1,79 @@
+/*
+ * Copyright 2015 Anton Tananaev (anton.tananaev@gmail.com)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
 package org.traccar.helper;
 
-import java.io.UnsupportedEncodingException;
-import java.security.MessageDigest;
-import java.security.NoSuchAlgorithmException;
+import javax.crypto.SecretKeyFactory;
+import javax.crypto.spec.PBEKeySpec;
+import java.security.GeneralSecurityException;
+import java.security.SecureRandom;
 
 public class Hashing {
-    
-    public static byte[] sha256(String text) {
+
+    public static final int ITERATIONS = 1000;
+    public static final int SALT_SIZE = 24;
+    public static final int HASH_SIZE = 24;
+
+    public static class HashingResult {
+
+        public final String hash;
+        public final String salt;
+
+        public HashingResult(String hash, String salt) {
+            this.hash = hash;
+            this.salt = salt;
+        }
+    }
+
+    private static byte[] function(char[] password, byte[] salt) {
         try {
-            MessageDigest md = MessageDigest.getInstance("SHA-256");
-            md.update(text.getBytes("UTF-8"));
-            return md.digest();
-        } catch (NoSuchAlgorithmException e) {
-            throw new RuntimeException(e);
-        } catch (UnsupportedEncodingException e) {
-            throw new RuntimeException(e);
+            PBEKeySpec spec = new PBEKeySpec(password, salt, ITERATIONS, HASH_SIZE * Byte.SIZE);
+            SecretKeyFactory factory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1");
+            return factory.generateSecret(spec).getEncoded();
+        } catch (GeneralSecurityException error) {
+            throw new SecurityException(error);
+        }
+    }
+
+    private static SecureRandom random = new SecureRandom();
+
+    public static HashingResult createHash(String password) {
+        byte[] salt = new byte[SALT_SIZE]; random.nextBytes(salt);
+        byte[] hash = function(password.toCharArray(), salt);
+        return new HashingResult(
+                ChannelBufferTools.convertByteArray(hash),
+                ChannelBufferTools.convertByteArray(salt));
+    }
+
+    public static boolean validatePassword(String password, String hashHex, String saltHex) {
+        byte[] hash = ChannelBufferTools.convertHexString(hashHex);
+        byte[] salt = ChannelBufferTools.convertHexString(saltHex);
+        return slowEquals(hash, function(password.toCharArray(), salt));
+    }
+
+    /**
+     * Compares two byte arrays in length-constant time. This comparison method
+     * is used so that password hashes cannot be extracted from an on-line
+     * system using a timing attack and then attacked off-line.
+     */
+    private static boolean slowEquals(byte[] a, byte[] b) {
+        int diff = a.length ^ b.length;
+        for (int i = 0; i < a.length && i < b.length; i++) {
+            diff |= a[i] ^ b[i];
         }
+        return diff == 0;
     }
 
 }