Readded PswdHashing and saltgeneration

src/main/java/dao/UserDAO.java

@@ -184,7 +184,8 @@ public class UserDAO {
      * @return a random salt
      */
     public byte[] generateSalt() {
-        return null;
+        SecureRandom random = new SecureRandom();
+        return random.generateSeed(16);
     }
 
     /**
@@ -194,9 +195,22 @@ public class UserDAO {
      * @return hashedPassword, null if unsuccessful
      */
     public String hashPassword(String password, byte[] salt) {
+        try {
+            MessageDigest md = java.security.MessageDigest.getInstance("SHA-256");
+            md.update(salt);
+            byte[] digest = (md.digest(password.getBytes()));
+            StringBuilder stringBuilder = new StringBuilder();
+            for(int i = 0; i < digest.length; i++){
+                stringBuilder.append(Integer.toString((digest[i] & 0xff) + 0x100,
+                    16).substring(1));
+            }
+            return stringBuilder.toString();
+        } catch (Exception e) {
             return null;
         }
 
+    }
+
     /**
      * Edits the users username or password
      * @param userId userId as int