diff --git a/app/src/main/AndroidManifest.xml b/app/src/main/AndroidManifest.xml
index e47f23f..7c69652 100644
--- a/app/src/main/AndroidManifest.xml
+++ b/app/src/main/AndroidManifest.xml
@@ -10,10 +10,14 @@
         android:roundIcon="@mipmap/ic_launcher_round"
         android:supportsRtl="true"
         android:theme="@style/AppTheme">
+        <activity
+            android:name=".ChangePassword"
+            android:label="@string/title_activity_change_password"
+            android:theme="@style/AppTheme.NoActionBar"></activity>
         <activity
             android:name=".NotebookActivity"
             android:label="@string/title_activity_notebook"
-            android:theme="@style/AppTheme.NoActionBar"></activity>
+            android:theme="@style/AppTheme.NoActionBar" />
         <activity
             android:name=".SetPasswordActivity"
             android:label="@string/title_activity_set_password"
diff --git a/app/src/main/java/com/example/encryptednotebook/ChangePassword.java b/app/src/main/java/com/example/encryptednotebook/ChangePassword.java
new file mode 100644
index 0000000..7670e22
--- /dev/null
+++ b/app/src/main/java/com/example/encryptednotebook/ChangePassword.java
@@ -0,0 +1,95 @@
+package com.example.encryptednotebook;
+
+import android.app.Activity;
+import android.content.Intent;
+import android.content.SharedPreferences;
+import android.os.Bundle;
+
+import com.google.android.material.floatingactionbutton.FloatingActionButton;
+import com.google.android.material.snackbar.Snackbar;
+
+import androidx.appcompat.app.AppCompatActivity;
+import androidx.appcompat.widget.Toolbar;
+
+import android.preference.PreferenceManager;
+import android.view.View;
+import android.widget.EditText;
+
+import javax.crypto.SecretKey;
+
+import static com.example.encryptednotebook.Cipher.decryptMsg;
+import static com.example.encryptednotebook.Cipher.encryptMsg;
+import static com.example.encryptednotebook.Cipher.generateKey;
+
+public class ChangePassword extends AppCompatActivity {
+
+    @Override
+    protected void onCreate(final Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        setContentView(R.layout.activity_change_password);
+        Toolbar toolbar = findViewById(R.id.toolbar);
+        setSupportActionBar(toolbar);
+
+        FloatingActionButton fab = findViewById(R.id.fab);
+        fab.setOnClickListener(new View.OnClickListener() {
+            @Override
+            public void onClick(View view) {
+                EditText setPass1 = findViewById(R.id.setPass1);
+                String setPass1Value = setPass1.getText().toString();
+                EditText setPass2 = findViewById(R.id.setPass2);
+                String setPass2Value = setPass2.getText().toString();
+                if (setPass1Value.equals(setPass2Value)) {
+                    try {
+                        String encryptedText = PreferenceManager.getDefaultSharedPreferences(getApplicationContext()).getString("TEXT", null);
+                        SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
+
+                        try {
+                            EditText password = findViewById(R.id.oldPass);
+                            String passValue = password.getText().toString();
+                            String savedPassValue = PreferenceManager.getDefaultSharedPreferences(getApplicationContext()).getString("PASSWORD", null);
+                            SecretKey oldSecretKey = generateKey(passValue, getApplicationContext());
+                            String savedPassValueDecrypted = decryptMsg(savedPassValue, oldSecretKey);
+                            if (passValue.equals(savedPassValueDecrypted)) {
+                                Snackbar.make(view, "Dobre hasło", Snackbar.LENGTH_LONG)
+                                        .setAction("Action", null).show();
+
+                                SecretKey newSecretKey = generateKey(setPass2Value, getApplicationContext());
+                                String encryptedText = encryptMsg(setPass2Value, newSecretKey);
+                                prefs.edit().putBoolean("PASSWORD_CREATED", true).apply();
+                                prefs.edit().putString("PASSWORD", encryptedText).apply();
+
+                                String encryptedOldText = PreferenceManager.getDefaultSharedPreferences(getApplicationContext()).getString("TEXT", null);
+                                if(encryptedOldText!=null){
+                                    String decrptedText = decryptMsg(encryptedOldText, oldSecretKey);
+                                    String encrptedNewText = encryptMsg(decrptedText, newSecretKey);
+                                    PreferenceManager.getDefaultSharedPreferences(getApplicationContext()).edit().putString("TEXT", encrptedNewText).apply();
+                                    Intent resultIntent = new Intent();
+                                    setResult(Activity.RESULT_OK, resultIntent);
+                                    finish();
+                                }
+
+                            } else {
+                                Snackbar.make(view, "Złe hasło", Snackbar.LENGTH_LONG)
+                                        .setAction("Action", null).show();
+                            }
+                        }catch(Exception e){
+                            e.printStackTrace();
+                            Snackbar.make(view, "Złe hasło", Snackbar.LENGTH_LONG)
+                                    .setAction("Action", null).show();
+                        }
+
+
+
+
+                    }catch (Exception e){
+                        e.printStackTrace();
+                    }
+                } else {
+                    Snackbar.make(view, "Hasła się różnią, wpisz takie same hasła", Snackbar.LENGTH_LONG)
+                            .setAction("Action", null).show();
+                }
+            }
+        });
+    }
+
+}
diff --git a/app/src/main/java/com/example/encryptednotebook/SetPasswordActivity.java b/app/src/main/java/com/example/encryptednotebook/SetPasswordActivity.java
index c0515b7..ba9452d 100644
--- a/app/src/main/java/com/example/encryptednotebook/SetPasswordActivity.java
+++ b/app/src/main/java/com/example/encryptednotebook/SetPasswordActivity.java
@@ -17,6 +17,7 @@ import android.widget.EditText;
 
 import javax.crypto.SecretKey;
 
+import static com.example.encryptednotebook.Cipher.decryptMsg;
 import static com.example.encryptednotebook.Cipher.encryptMsg;
 import static com.example.encryptednotebook.Cipher.generateKey;
 
@@ -57,5 +58,4 @@ public class SetPasswordActivity extends AppCompatActivity {
             }
         });
     }
-
 }
diff --git a/app/src/main/res/layout/activity_change_password.xml b/app/src/main/res/layout/activity_change_password.xml
new file mode 100644
index 0000000..5cd9056
--- /dev/null
+++ b/app/src/main/res/layout/activity_change_password.xml
@@ -0,0 +1,33 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.coordinatorlayout.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    tools:context=".ChangePassword">
+
+    <com.google.android.material.appbar.AppBarLayout
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:theme="@style/AppTheme.AppBarOverlay">
+
+        <androidx.appcompat.widget.Toolbar
+            android:id="@+id/toolbar"
+            android:layout_width="match_parent"
+            android:layout_height="?attr/actionBarSize"
+            android:background="?attr/colorPrimary"
+            app:popupTheme="@style/AppTheme.PopupOverlay" />
+
+    </com.google.android.material.appbar.AppBarLayout>
+
+    <include layout="@layout/content_change_password" />
+
+    <com.google.android.material.floatingactionbutton.FloatingActionButton
+        android:id="@+id/fab"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_gravity="bottom|end"
+        android:layout_margin="@dimen/fab_margin"
+        app:srcCompat="@android:drawable/ic_dialog_email" />
+
+</androidx.coordinatorlayout.widget.CoordinatorLayout>
\ No newline at end of file
diff --git a/app/src/main/res/layout/content_change_password.xml b/app/src/main/res/layout/content_change_password.xml
new file mode 100644
index 0000000..be600c9
--- /dev/null
+++ b/app/src/main/res/layout/content_change_password.xml
@@ -0,0 +1,61 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    app:layout_behavior="@string/appbar_scrolling_view_behavior"
+    tools:context=".ChangePassword"
+    tools:showIn="@layout/activity_change_password">
+
+    <TextView
+        android:id="@+id/setPassLabel"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:text="Stare hasło"
+        app:layout_constraintLeft_toLeftOf="parent"
+        app:layout_constraintRight_toRightOf="parent"
+        app:layout_constraintTop_toTopOf="parent"
+        android:layout_marginTop="200dp"/>
+
+    <EditText
+        android:id="@+id/oldPass"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:ems="10"
+        android:inputType="textPassword"
+        app:layout_constraintTop_toBottomOf="@+id/setPassLabel"
+        app:layout_constraintLeft_toLeftOf="parent"
+        app:layout_constraintRight_toRightOf="parent" />
+
+
+    <TextView
+        android:id="@+id/setPassLabel2"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:text="Nowe hasło"
+        app:layout_constraintTop_toBottomOf="@+id/oldPass"
+        app:layout_constraintLeft_toLeftOf="parent"
+        app:layout_constraintRight_toRightOf="parent" />
+
+    <EditText
+        android:id="@+id/setPass1"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:ems="10"
+        android:inputType="textPassword"
+        app:layout_constraintTop_toBottomOf="@+id/setPassLabel2"
+        app:layout_constraintLeft_toLeftOf="parent"
+        app:layout_constraintRight_toRightOf="parent" />
+
+    <EditText
+        android:id="@+id/setPass2"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:ems="10"
+        android:inputType="textPassword"
+        app:layout_constraintTop_toBottomOf="@+id/setPass1"
+        app:layout_constraintLeft_toLeftOf="parent"
+        app:layout_constraintRight_toRightOf="parent" />
+
+</androidx.constraintlayout.widget.ConstraintLayout>
\ No newline at end of file
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index 6d2746b..670b910 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -3,4 +3,5 @@
     <string name="action_settings">Settings</string>
     <string name="title_activity_set_password">SetPasswordActivity</string>
     <string name="title_activity_notebook">NotebookActivity</string>
+    <string name="title_activity_change_password">ChangePassword</string>
 </resources>