Introduce a PublicKeyEncryptionService for easier ShadowFlow configur…

…ation through starter

src/main/java/io/github/rabobank/shadow_tool/DefaultEncryptionService.java

@@ -3,19 +3,27 @@
 import org.bouncycastle.util.encoders.Base64;
 
 import javax.crypto.Cipher;
+import java.security.GeneralSecurityException;
 
-class DefaultEncryptionService implements EncryptionService {
+import static java.nio.charset.StandardCharsets.UTF_8;
+
+/**
+ * The default Encryption Service used by Shadow Tool. It uses a {@link Cipher} to encrypt values.
+ *
+ * @see Cipher
+ */
+public class DefaultEncryptionService implements EncryptionService {
     private final Cipher cipher;
 
-    DefaultEncryptionService(final Cipher cipher) {
+    public DefaultEncryptionService(final Cipher cipher) {
         this.cipher = cipher;
     }
 
     @Override
     public String encrypt(final String value) {
         try {
-            return Base64.toBase64String(cipher.doFinal(value.getBytes()));
-        } catch (final Exception e) {
+            return Base64.toBase64String(cipher.doFinal(value.getBytes(UTF_8)));
+        } catch (final GeneralSecurityException e) {
             throw new SecurityException(e);
         }
     }

src/main/java/io/github/rabobank/shadow_tool/PublicKeyEncryptionService.java

@@ -0,0 +1,30 @@
+package io.github.rabobank.shadow_tool;
+
+import javax.crypto.Cipher;
+import java.security.GeneralSecurityException;
+import java.security.PublicKey;
+
+import static javax.crypto.Cipher.ENCRYPT_MODE;
+
+/**
+ * A version of the Encryption Service that uses a {@link PublicKey} to encrypt the values.
+ */
+public class PublicKeyEncryptionService extends DefaultEncryptionService {
+    private static final String DEFAULT_ALGORITHM = "RSA";
+    private static final String DEFAULT_ALGORITHM_MODE_PADDING =
+            DEFAULT_ALGORITHM + "/ECB/OAEPWITHSHA-256ANDMGF1PADDING";
+
+    public PublicKeyEncryptionService(final PublicKey publicKey) {
+        super(createCipher(publicKey));
+    }
+
+    private static Cipher createCipher(final PublicKey publicKey) {
+        try {
+            final var cipher = Cipher.getInstance(DEFAULT_ALGORITHM_MODE_PADDING);
+            cipher.init(ENCRYPT_MODE, publicKey);
+            return cipher;
+        } catch (final GeneralSecurityException e) {
+            throw new IllegalArgumentException(e);
+        }
+    }
+}

src/main/java/io/github/rabobank/shadow_tool/ShadowFlow.java

@@ -37,9 +37,6 @@ public class ShadowFlow<T> {
     private static final String DEFAULT_INSTANCE_NAME = "default";
     private static final String CALLING_NEW_FLOW = "{} Calling new flow: {}";
     private static final String FAILED_TO_COMPARE = "{} Failed to run the shadow flow";
-    private static final String DEFAULT_ALGORITHM = "RSA";
-    private static final String DEFAULT_ALGORITHM_MODE_PADDING =
-            DEFAULT_ALGORITHM + "/ECB/OAEPWITHSHA-256ANDMGF1PADDING";
     private final int percentage;
     private final ExecutorService executorService;
     private final EncryptionService encryptionService;
@@ -285,13 +282,7 @@ public ShadowFlowBuilder<T> withExecutorService(final ExecutorService executorSe
          */
         public ShadowFlowBuilder<T> withEncryption(final PublicKey publicKey) {
             requireNull();
-            try {
-                final var cipher = Cipher.getInstance(DEFAULT_ALGORITHM_MODE_PADDING);
-                cipher.init(Cipher.ENCRYPT_MODE, publicKey);
-                withCipher(cipher);
-            } catch (final Exception e) {
-                logger.error("Invalid encryption setup. Encryption and logging of values is disabled", e);
-            }
+            withEncryptionService(new PublicKeyEncryptionService(publicKey));
             return this;
         }
 
@@ -306,7 +297,7 @@ public ShadowFlowBuilder<T> withEncryption(final PublicKey publicKey) {
          */
         public ShadowFlowBuilder<T> withCipher(final Cipher cipher) {
             requireNull();
-            encryptionService = new DefaultEncryptionService(cipher);
+            withEncryptionService(new DefaultEncryptionService(cipher));
             return this;
         }
 
@@ -320,7 +311,11 @@ public ShadowFlowBuilder<T> withCipher(final Cipher cipher) {
          */
         public ShadowFlowBuilder<T> withEncryptionService(final EncryptionService encryptionService) {
             requireNull();
-            this.encryptionService = encryptionService;
+            try {
+                this.encryptionService = encryptionService;
+            } catch (final Exception e) {
+                logger.error("Invalid encryption setup. Encryption and logging of values is disabled", e);
+            }
             return this;
         }
 

src/test/java/io/github/rabobank/shadow_tool/EncryptionServiceTest.java

@@ -4,14 +4,13 @@
 import org.junit.jupiter.api.Test;
 
 import javax.crypto.Cipher;
+import java.security.GeneralSecurityException;
 import java.security.KeyPairGenerator;
-import java.security.NoSuchAlgorithmException;
 import java.security.PrivateKey;
 import java.security.PublicKey;
 
 import static java.nio.charset.StandardCharsets.UTF_8;
 import static javax.crypto.Cipher.DECRYPT_MODE;
-import static javax.crypto.Cipher.ENCRYPT_MODE;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 
@@ -26,16 +25,14 @@ class EncryptionServiceTest {
             final var pair = keyPairGen.generateKeyPair();
             PRIVATE_KEY = pair.getPrivate();
             PUBLIC_KEY = pair.getPublic();
-        } catch (NoSuchAlgorithmException e) {
+        } catch (final GeneralSecurityException e) {
             throw new RuntimeException(e);
         }
     }
 
     @Test
     void encryptAndDecrypt() throws Exception {
-        final var encryptCipher = Cipher.getInstance("RSA/ECB/OAEPWITHSHA-256ANDMGF1PADDING");
-        encryptCipher.init(ENCRYPT_MODE, PUBLIC_KEY);
-        final var encryptionService = new DefaultEncryptionService(encryptCipher);
+        final var encryptionService = new PublicKeyEncryptionService(PUBLIC_KEY);
         final var plainDifferences = "'place' changed: 'Dintelooord' -> 'Dinteloord'\n" +
                                      "'madrigals' collection changes :\n" +
                                      "   1. 'Bruno' changed to 'Mirabel'\n" +
@@ -58,7 +55,7 @@ void encryptAndForgotToInitCipher() throws Exception {
                                      "'madrigals' collection changes :\n" +
                                      "   1. 'Bruno' changed to 'Mirabel'\n" +
                                      "   0. 'Bruno' added";
-        final var exception = assertThrows(SecurityException.class, () -> encryptionService.encrypt(plainDifferences));
-        assertEquals("java.lang.IllegalStateException: Cipher not initialized", exception.getMessage());
+        final var exception = assertThrows(IllegalStateException.class, () -> encryptionService.encrypt(plainDifferences));
+        assertEquals("Cipher not initialized", exception.getMessage());
     }
 }