diff --git a/src/identiconpp.hpp b/src/identiconpp.hpp
index 8170234..f5517e7 100644
--- a/src/identiconpp.hpp
+++ b/src/identiconpp.hpp
@@ -42,6 +42,7 @@ using std::array;
 class Identiconpp
 {
 public:
+    friend class Testiconpp;
     /*!
      * @brief  List of identicon algorithms
      */
@@ -89,7 +90,7 @@ public:
      */
     Magick::Image generate(const string &digest, const uint16_t width = 100);
 
-protected:
+private:
     const uint8_t _rows;
     const uint8_t _columns;
     const algorithm _type;
diff --git a/src/tests/test_checks_entropy.cpp b/src/tests/test_checks_entropy.cpp
index 72000da..c15d3c4 100644
--- a/src/tests/test_checks_entropy.cpp
+++ b/src/tests/test_checks_entropy.cpp
@@ -6,7 +6,7 @@
 
 using std::string;
 
-class Testiconpp : protected Identiconpp
+class Testiconpp : private Identiconpp
 {
 public:
     explicit Testiconpp(const uint8_t columns, const uint8_t rows,
diff --git a/src/tests/test_checks_hex.cpp b/src/tests/test_checks_hex.cpp
index 27c0c6e..c438b06 100644
--- a/src/tests/test_checks_hex.cpp
+++ b/src/tests/test_checks_hex.cpp
@@ -6,7 +6,7 @@
 
 using std::string;
 
-class Testiconpp : protected Identiconpp
+class Testiconpp : private Identiconpp
 {
 public:
     explicit Testiconpp()