Initial basic version of project.

pom.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+
+  <groupId>de.denisthiessen</groupId>
+  <artifactId>simpleencryptor</artifactId>
+  <version>1.0-SNAPSHOT</version>
+
+  <name>simpleencryptor</name>
+  <!-- FIXME change it to the project's website -->
+  <url>http://www.example.com</url>
+
+  <properties>
+    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    <maven.compiler.source>1.7</maven.compiler.source>
+    <maven.compiler.target>1.7</maven.compiler.target>
+  </properties>
+
+  <dependencies>
+    <dependency>
+      <groupId>junit</groupId>
+      <artifactId>junit</artifactId>
+      <version>4.11</version>
+      <scope>test</scope>
+    </dependency>
+  </dependencies>
+
+  <build>
+    <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
+      <plugins>
+        <!-- clean lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#clean_Lifecycle -->
+        <plugin>
+          <artifactId>maven-clean-plugin</artifactId>
+          <version>3.1.0</version>
+        </plugin>
+        <!-- default lifecycle, jar packaging: see https://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_jar_packaging -->
+        <plugin>
+          <artifactId>maven-resources-plugin</artifactId>
+          <version>3.0.2</version>
+        </plugin>
+        <plugin>
+          <artifactId>maven-compiler-plugin</artifactId>
+          <version>3.8.0</version>
+        </plugin>
+        <plugin>
+          <artifactId>maven-surefire-plugin</artifactId>
+          <version>2.22.1</version>
+        </plugin>
+        <plugin>
+          <artifactId>maven-jar-plugin</artifactId>
+          <version>3.0.2</version>
+        </plugin>
+        <plugin>
+          <artifactId>maven-install-plugin</artifactId>
+          <version>2.5.2</version>
+        </plugin>
+        <plugin>
+          <artifactId>maven-deploy-plugin</artifactId>
+          <version>2.8.2</version>
+        </plugin>
+        <!-- site lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#site_Lifecycle -->
+        <plugin>
+          <artifactId>maven-site-plugin</artifactId>
+          <version>3.7.1</version>
+        </plugin>
+        <plugin>
+          <artifactId>maven-project-info-reports-plugin</artifactId>
+          <version>3.0.0</version>
+        </plugin>
+      </plugins>
+    </pluginManagement>
+  </build>
+</project>

src/main/java/de/denisthiessen/AlgorithmFactory.java

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+package de.denisthiessen;
+
+import de.denisthiessen.algorithms.CaesarAlgorithm;
+import de.denisthiessen.algorithms.HashingAlgorithm;
+import de.denisthiessen.algorithms.IAlgorithm;
+import de.denisthiessen.algorithms.NoEncryptionAlgorithm;
+import de.denisthiessen.algorithms.Rot13Algorithm;
+import de.denisthiessen.algorithms.XORAlgorithm;
+
+public class AlgorithmFactory {
+    
+    public static IAlgorithm getEncryptionAlgorithm(String algorithm) {
+     
+            switch(algorithm) {
+                case "rot13": return new Rot13Algorithm();
+                case "hash": return new HashingAlgorithm();
+                case "xor": return new XORAlgorithm();
+                case "caesar": return new CaesarAlgorithm();
+                default : return new NoEncryptionAlgorithm();
+            }
+    }
+}

src/main/java/de/denisthiessen/App.java

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+package de.denisthiessen;
+
+import java.util.Scanner;
+
+import de.denisthiessen.algorithms.IAlgorithm;
+
+public class App 
+{
+    public static void main( String[] args )
+    {
+        Scanner scanner = new Scanner(System.in);
+        System.out.print("Enter your encryption algorithm: ");
+        String algorithm = scanner.nextLine();
+
+        System.out.print("Enter your source text: ");
+        String sourceText = scanner.nextLine();
+
+        scanner.close();
+
+        IAlgorithm encryptionAlgorithm = AlgorithmFactory.getEncryptionAlgorithm(algorithm);
+        String encryptedText = encryptionAlgorithm.executeAlgorithm(sourceText);
+
+        System.out.println(encryptedText);
+    }
+}

src/main/java/de/denisthiessen/algorithms/CaesarAlgorithm.java

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+package de.denisthiessen.algorithms;
+
+public class CaesarAlgorithm implements IAlgorithm {
+
+    public CaesarAlgorithm() {
+
+    }
+
+    @Override
+    public String executeAlgorithm(String sourceString) {
+        int shift = 42;
+        StringBuilder encryptedText = new StringBuilder();
+        for (char c : sourceString.toCharArray()) {
+            if (Character.isLetter(c)) {
+                char base = Character.isLowerCase(c) ? 'a' : 'A';
+                encryptedText.append((char) (((c - base + shift) % 26) + base));
+            } else {
+                encryptedText.append(c);
+            }
+        }
+        return encryptedText.toString();
+    }
+    
+}

src/main/java/de/denisthiessen/algorithms/HashingAlgorithm.java

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+package de.denisthiessen.algorithms;
+
+public class HashingAlgorithm implements IAlgorithm {
+
+    public HashingAlgorithm() {
+
+    }
+
+    @Override
+    public String executeAlgorithm(String sourceString) {
+        int hashCode = 7;
+        char[] inputCharacters = sourceString.toCharArray();
+    
+        for(char character : inputCharacters) {
+            hashCode = hashCode*31 + ((int)character);
+        }
+    
+        return String.valueOf(hashCode);
+    }
+}

src/main/java/de/denisthiessen/algorithms/IAlgorithm.java

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+package de.denisthiessen.algorithms;
+
+public interface IAlgorithm {
+    
+    public String executeAlgorithm(String sourceString);
+
+}

src/main/java/de/denisthiessen/algorithms/NoEncryptionAlgorithm.java

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+package de.denisthiessen.algorithms;
+
+public class NoEncryptionAlgorithm implements IAlgorithm {
+
+    public NoEncryptionAlgorithm() {
+
+    }
+
+    @Override
+    public String executeAlgorithm(String sourceString) {
+        return sourceString;
+    }
+}

src/main/java/de/denisthiessen/algorithms/Rot13Algorithm.java

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+package de.denisthiessen.algorithms;
+
+public class Rot13Algorithm implements IAlgorithm {
+
+    public Rot13Algorithm() {
+
+    }
+
+    @Override
+    public String executeAlgorithm(String sourceString) {
+        StringBuilder sb = new StringBuilder();
+
+        for (int i = 0; i < sourceString.length(); i++) {
+            char c = sourceString.charAt(i);
+            if (c >= 'a' && c <= 'm')
+                c += 13;
+            else if (c >= 'A' && c <= 'M')
+                c += 13;
+            else if (c >= 'n' && c <= 'z')
+                c -= 13;
+            else if (c >= 'N' && c <= 'Z')
+                c -= 13;
+            sb.append(c);
+        }
+        
+        return sb.toString();
+    }
+}

src/main/java/de/denisthiessen/algorithms/XORAlgorithm.java

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+package de.denisthiessen.algorithms;
+
+public class XORAlgorithm implements IAlgorithm {
+
+    public XORAlgorithm() {
+
+    }
+
+    @Override
+    public String executeAlgorithm(String sourceString) {
+
+        String key = "secretkey";
+        StringBuilder encryptedText = new StringBuilder();
+        for (int i = 0; i < sourceString.length(); i++) {
+            char plainChar = sourceString.charAt(i);
+            char keyChar = key.charAt(i % key.length());
+
+            // XOR the plaintext character with the corresponding key character
+            char encryptedChar = (char) (plainChar ^ keyChar);
+            encryptedText.append(encryptedChar);
+        }
+        return encryptedText.toString();
+    }
+}

src/test/java/de/denisthiessen/AppTest.java

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+package de.denisthiessen;
+
+import static org.junit.Assert.assertTrue;
+
+import org.junit.Test;
+
+import de.denisthiessen.algorithms.IAlgorithm;
+
+/**
+ * Unit test for simple encryptor.
+ */
+public class AppTest 
+{
+    @Test
+    public void testCasesarCipher()
+    {
+        IAlgorithm encryptionAlgorithm = AlgorithmFactory.getEncryptionAlgorithm("caesar");
+        String encryptedText = encryptionAlgorithm.executeAlgorithm("Helloworld");
+        System.out.println(encryptedText);
+
+        assertTrue(encryptedText.equals("Xubbemehbt"));
+    }
+
+    @Test
+    public void testXorCipher()
+    {
+        IAlgorithm encryptionAlgorithm = AlgorithmFactory.getEncryptionAlgorithm("xor");
+        String encryptedText = encryptionAlgorithm.executeAlgorithm("test");
+        System.out.println(encryptedText);
+        String expectedText = new String(new byte[]{7, 0, 16, 6});
+
+        assertTrue(encryptedText.equals(expectedText));
+    }
+
+    @Test
+    public void testHashingCipher()
+    {
+        IAlgorithm encryptionAlgorithm = AlgorithmFactory.getEncryptionAlgorithm("hash");
+        String encryptedText = encryptionAlgorithm.executeAlgorithm("Helloworld");
+
+        assertTrue(encryptedText.equals("775124327"));
+    }
+
+    @Test
+    public void testRot13Cipher()
+    {
+        IAlgorithm encryptionAlgorithm = AlgorithmFactory.getEncryptionAlgorithm("rot13");
+        String encryptedText = encryptionAlgorithm.executeAlgorithm("Helloworld");
+
+        assertTrue(encryptedText.equals("Uryybjbeyq"));
+    }
+
+    @Test
+    public void testNoCipher()
+    {
+        IAlgorithm encryptionAlgorithm = AlgorithmFactory.getEncryptionAlgorithm("nocipher");
+        String encryptedText = encryptionAlgorithm.executeAlgorithm("Helloworld");
+
+        assertTrue(encryptedText.equals("Helloworld"));
+    }
+}