diff --git a/src/main/java/Credential.java b/src/main/java/Credential.java
new file mode 100644
index 0000000..506fdb7
--- /dev/null
+++ b/src/main/java/Credential.java
@@ -0,0 +1,31 @@
+public class Credential {
+
+    private String name, password;
+    private int id;
+
+
+    public Credential(String name, String password, int id) throws Exception {
+        if(name == null || password == null)
+            throw new Exception("kein leeres Objekt erstellen");
+
+        this.name = name;
+        this.password = password;
+    }
+
+    public String getName()
+    {
+        return this.name;
+    }
+    public String getPassword() { return this.password; }
+    public int getId() { return this.id; }
+
+    public void upDatePassword(String newPassword)
+    {
+        this.password = newPassword;
+    }
+
+    public void updateUsername(String newUsername)
+    {
+        this.name = newUsername;
+    }
+}
diff --git a/src/main/java/CredentialInterface.java b/src/main/java/CredentialInterface.java
deleted file mode 100644
index f6e0ead..0000000
--- a/src/main/java/CredentialInterface.java
+++ /dev/null
@@ -1,11 +0,0 @@
-public interface CredentialInterface {
-
-    public void show();
-    public void edit();
-    public void delete();
-    public void getCredentials();
-    public void setCredentials();
-    public void getAsJSON();
-    public void loadCredentialsFromJSON();
-
-}
diff --git a/src/main/java/CredentialRepository.java b/src/main/java/CredentialRepository.java
new file mode 100644
index 0000000..6a048cc
--- /dev/null
+++ b/src/main/java/CredentialRepository.java
@@ -0,0 +1,116 @@
+import java.util.ArrayList;
+
+public class CredentialRepository implements CredentialRepositoryInterface{
+
+    private int idCounter = 0;
+    private ArrayList<Credential> credentials;
+
+    public CredentialRepository()
+    {
+        this.credentials = new ArrayList<Credential>();
+    }
+
+    public int createNewCredential(String name, String password)
+    {
+        try {
+            this.credentials.add(new Credential(name, password, this.idCounter++));
+        }
+        catch(Exception fail)
+        {
+            System.err.println(fail.getMessage());
+        }
+
+        return this.getListSize();
+    }
+
+    @Override
+    public Credential getCredentialsViaName(String needle) {
+
+        for(int c = 0; c < this.getListSize(); c++)
+        {
+            Credential credential = this.credentials.get(c);
+
+            if(credential.getName().equals(needle))
+                return credential;
+        }
+
+        return null;
+    }
+
+
+    @Override
+    public Credential getCredentialsViaId(int id) {
+
+        try{
+            return this.credentials.get(id);
+        }
+        catch (IndexOutOfBoundsException outOfBoundsException)
+        {
+           return null;
+        }
+
+    }
+
+    /*
+            The next 3 functions assume you already have successfully
+            pulled a credential from the repository and now want to edit it.
+            Thus, these functions require you to pass the desired credential's index
+     */
+
+
+    @Override
+    public void updatePassword(int index, String newPassword) {
+
+        try{
+            this.credentials.get(index).upDatePassword(newPassword);
+        }
+        catch (IndexOutOfBoundsException outOfBoundsException)
+        {
+            System.err.println("No Credential with Index" + index + " found");
+        }
+
+    }
+
+    public void updateUsername(int index, String newUsername){
+
+        try{
+            this.credentials.get(index).updateUsername(newUsername);
+        }
+        catch (IndexOutOfBoundsException outOfBoundsException)
+        {
+            System.err.println("No Credential with Index" + index + " found");
+        }
+    }
+
+    @Override
+    public void delete(int index) {
+
+        this.credentials.remove(index);
+
+    }
+
+/*
+    this function will be required in the future for catching the left-shift in the arrayList
+    after one entry was deleted. welp, maybe it won't. can't tell and i've no time atm to
+    finish this
+
+
+    private int mapIndexToListCounter(int needle) {
+        for(int c = 0; c<this.credentials.size(); c++)
+        {
+            if(this.credentials.get(c).getId() == needle)
+            {
+                return c;
+            }
+        }
+        return -1;
+    }
+*/
+    private int getListSize()
+    {
+        return this.credentials.size();
+    }
+
+}
+
+
diff --git a/src/main/java/CredentialRepositoryInterface.java b/src/main/java/CredentialRepositoryInterface.java
new file mode 100644
index 0000000..afff4b0
--- /dev/null
+++ b/src/main/java/CredentialRepositoryInterface.java
@@ -0,0 +1,10 @@
+public interface CredentialRepositoryInterface {
+
+    int createNewCredential(String name, String password);
+    Credential getCredentialsViaName(String needle);
+    Credential getCredentialsViaId(int id);
+    void updatePassword(int index, String newPassword);
+    void updateUsername(int indexl, String newUsername);
+    void delete(int index);
+
+}
diff --git a/src/main/java/Credentials.java b/src/main/java/Credentials.java
deleted file mode 100644
index 028f58b..0000000
--- a/src/main/java/Credentials.java
+++ /dev/null
@@ -1,38 +0,0 @@
-public class Credentials implements CredentialInterface{
-    @Override
-    public void show() {
-
-    }
-
-    @Override
-    public void edit() {
-
-    }
-
-    @Override
-    public void delete() {
-
-    }
-
-    @Override
-    public void getCredentials() {
-
-    }
-
-    @Override
-    public void setCredentials() {
-
-    }
-
-    @Override
-    public void getAsJSON() {
-
-    }
-
-    @Override
-    public void loadCredentialsFromJSON() {
-
-    }
-}
-
-
diff --git a/src/test/java/CredentialRepositoryTest.java b/src/test/java/CredentialRepositoryTest.java
new file mode 100644
index 0000000..9feb527
--- /dev/null
+++ b/src/test/java/CredentialRepositoryTest.java
@@ -0,0 +1,84 @@
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.Assertions;
+
+class CredentialRepositoryTest {
+
+
+    private CredentialRepository credentialRepository;
+
+    @BeforeEach
+    public void setUp()
+    {
+        credentialRepository = new CredentialRepository();
+    }
+
+    @Test
+    void createNewCredentialAndAddToList() {
+
+        Assertions.assertEquals(1, this.credentialRepository.createNewCredential("mock", "mock"));
+        Assertions.assertEquals(2, this.credentialRepository.createNewCredential("kek", "mate"));
+    }
+
+    @Test
+    void searchForUserInRepository() {
+
+         this.credentialRepository.createNewCredential("mock", "mock");
+         this.credentialRepository.createNewCredential("kek", "mate");
+
+         Credential c = this.credentialRepository.getCredentialsViaName("kek");
+         Assertions.assertEquals("mate", c.getPassword());
+    }
+
+    @Test
+    void searchForIdInRepository() {
+
+        this.credentialRepository.createNewCredential("mock", "mock");
+        this.credentialRepository.createNewCredential("kek", "mate");
+
+        Credential c = this.credentialRepository.getCredentialsViaId(1);
+        Assertions.assertEquals("mate", c.getPassword());
+    }
+
+    @Test
+    void testSearchWithInvalidIndex() {
+
+        this.credentialRepository.createNewCredential("mock", "mock");
+
+        Assertions.assertEquals(null, this.credentialRepository.getCredentialsViaId(2));
+
+    }
+
+    @Test
+    void testUpdatePassword(){
+
+        this.credentialRepository.createNewCredential("mock", "mock");
+        this.credentialRepository.updatePassword(0, "newPassword");
+
+        Credential c = this.credentialRepository.getCredentialsViaId(0);
+
+        Assertions.assertEquals("newPassword", c.getPassword());
+
+    }
+
+    @Test
+    void testUpdateUsername(){
+
+        this.credentialRepository.createNewCredential("mock", "mock");
+        this.credentialRepository.updateUsername(0, "newUsername");
+
+        Credential c = this.credentialRepository.getCredentialsViaId(0);
+
+        Assertions.assertEquals("newUsername", c.getName());
+    }
+
+    @Test
+    void testDeleteEntry(){
+
+        this.credentialRepository.createNewCredential("mock", "mock");
+        this.credentialRepository.delete(0);
+
+        Assertions.assertEquals(null, this.credentialRepository.getCredentialsViaId(0));
+    }
+
+}