diff --git a/CryptClass/AbstractSKA.hpp b/CryptClass/AbstractSKA.hpp
index b632149..791c1f6 100644
--- a/CryptClass/AbstractSKA.hpp
+++ b/CryptClass/AbstractSKA.hpp
@@ -9,12 +9,13 @@
  */
 
 
+
 /**
  * @class AbstractSKA AbstractSKA.hpp "/CryptClass/AbstractSKA.hpp"
  * @brief Class for Symmetric-Key Algorithm (SKA)
  * @author manzerbredes
  *
- * This should not be instanciate directly.
+ * This class should not be instanciate directly.
  *
  */
 
@@ -24,6 +25,25 @@ class AbstractSKA {
         AbstractSKA();
         ~AbstractSKA();
 
-        virtual void encrypt();
-        virtual void decrypt();
+       /**
+        * @brief Encrypt data.
+        *
+        * @param data : contain data to encrypt.
+        *
+        * This method must be overwritten.
+        * **Warning** data will be modified.
+        *
+        */
+        virtual void encrypt(char* data) = 0;
+
+       /**
+        * @brief Decrypt data.
+        *
+        * @param data : contain data to decrypt.
+        *
+        * This method must be overwritten.
+        * **Warning** data will be modified.
+        *
+        */
+        virtual void decrypt(char* data) = 0;
 };