#358 Start refactoring PasswordSecurity

- Add new methods temporarily to NewEncrMethod interface
   - No data source access within EncryptionMethod implementations
   - Generate the salt within the EncryptionMethod implementation
- Deprecate static methods on PasswordSecurity
- Adjust AbstractEncryptionMethodTest to test the classes with the new interface
- Add getter for data source instead of accessing field directly

src/main/java/fr/xephi/authme/security/crypts/EncryptionMethod.java

@@ -29,11 +29,8 @@ public interface EncryptionMethod {
      *
      * @return True if the password matches, false otherwise
      */
+    @Deprecated
     boolean comparePassword(String hash, String password, String playerName)
         throws NoSuchAlgorithmException;
 
-    // String generateSalt();
-
-    // String computeHash(String password, String name);
-
 }

src/main/java/fr/xephi/authme/security/crypts/HashResult.java

@@ -0,0 +1,26 @@
+package fr.xephi.authme.security.crypts;
+
+/**
+ * The result of a hash computation.
+ */
+public class HashResult {
+    
+    /** The generated hash. */
+    private final String hash;
+    /** The generated salt; may be null if no salt is used or if the salt is included in the hash output. */
+    private final String salt;
+    
+    public HashResult(String hash, String salt) {
+        this.hash = hash;
+        this.salt = salt;
+    }
+    
+    public String getHash() {
+        return hash;
+    }
+    
+    public String getSalt() {
+        return salt;
+    }
+    
+}

src/main/java/fr/xephi/authme/security/crypts/NewEncrMethod.java

@@ -0,0 +1,17 @@
+package fr.xephi.authme.security.crypts;
+
+/**
+ * Temporary interface for additional methods that will be added to {@link EncryptionMethod}.
+ * TODO #358: Move methods to EncryptionMethod interface and delete this.
+ */
+public interface NewEncrMethod extends EncryptionMethod {
+
+    HashResult computeHash(String password, String name);
+
+    String generateSalt();
+
+    boolean hasSeparateSalt();
+
+    boolean comparePassword(String hash, String password, String salt, String name);
+
+}

src/main/java/fr/xephi/authme/security/crypts/SALTED2MD5.java

@@ -1,14 +1,20 @@
 package fr.xephi.authme.security.crypts;
 
 import fr.xephi.authme.AuthMe;
+import fr.xephi.authme.security.RandomString;
+import fr.xephi.authme.security.crypts.description.HasSalt;
+import fr.xephi.authme.security.crypts.description.Recommendation;
+import fr.xephi.authme.security.crypts.description.SaltType;
+import fr.xephi.authme.security.crypts.description.Usage;
+import fr.xephi.authme.settings.Settings;
 
 import java.math.BigInteger;
 import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;
 
-/**
- */
-public class SALTED2MD5 implements EncryptionMethod {
+@Recommendation(Usage.ACCEPTABLE) // presuming that length is something sensible (>= 8)
+@HasSalt(value = SaltType.TEXT)   // length defined by Settings.saltLength
+public class SALTED2MD5 implements NewEncrMethod {
 
     private static String getMD5(String message)
         throws NoSuchAlgorithmException {
@@ -25,10 +31,41 @@ public class SALTED2MD5 implements EncryptionMethod {
         return getMD5(getMD5(password) + salt);
     }
 
+    @Override
+    public HashResult computeHash(String password, String name) {
+        try {
+            String salt = generateSalt();
+            return new HashResult(computeHash(password, salt, name), salt);
+        } catch (NoSuchAlgorithmException e) {
+            throw new RuntimeException(e); // TODO #358: Remove try-catch clause
+        }
+    }
+
     @Override
     public boolean comparePassword(String hash, String password,
                                    String playerName) throws NoSuchAlgorithmException {
         String salt = AuthMe.getInstance().database.getAuth(playerName).getSalt();
         return hash.equals(getMD5(getMD5(password) + salt));
     }
+
+    @Override
+    public boolean comparePassword(String hash, String password, String salt, String name) {
+        try {
+            return hash.equals(computeHash(password, salt, name));
+        } catch (NoSuchAlgorithmException e) {
+            throw new RuntimeException(e);
+            // TODO #358: Remove try-catch
+        }
+    }
+
+    @Override
+    public String generateSalt() {
+        return RandomString.generateHex(Settings.saltLength);
+    }
+
+    @Override
+    public boolean hasSeparateSalt() {
+        return true;
+    }
+
 }