BAEL-4487 Add Crypto Exceptions (#13183)

core-java-modules/core-java-security-2/README.md

@@ -13,4 +13,4 @@ This module contains articles about core Java Security
 - [Get a List of Trusted Certificates in Java](https://www.baeldung.com/java-list-trusted-certificates)
 - [Security Context Basics: User, Subject and Principal](https://www.baeldung.com/security-context-basics)
 - [The java.security.egd JVM Option](https://www.baeldung.com/java-security-egd)
-- More articles: [[<-- prev]](/core-java-modules/core-java-security)
+- More articles: [[<-- prev]](/core-java-modules/core-java-security) [[next -->]](/core-java-modules/core-java-security-3)

core-java-modules/core-java-security-3/src/main/java/com/baeldung/crypto/CryptoDriver.java

@@ -1,12 +1,11 @@
 package com.baeldung.crypto;
 
+import java.security.GeneralSecurityException;
+
 import javax.crypto.Cipher;
 import javax.crypto.SecretKey;
 import javax.crypto.spec.GCMParameterSpec;
 import javax.crypto.spec.IvParameterSpec;
-import java.security.GeneralSecurityException;
-
-import com.baeldung.crypto.utils.CryptoUtils;
 
 public class CryptoDriver {
 

core-java-modules/core-java-security-3/src/main/java/com/baeldung/crypto/exception/BadPaddingExamples.java

@@ -0,0 +1,66 @@
+package com.baeldung.crypto.exception;
+
+import java.security.GeneralSecurityException;
+import java.security.InvalidKeyException;
+
+import javax.crypto.Cipher;
+import javax.crypto.SecretKey;
+import javax.crypto.spec.IvParameterSpec;
+
+import com.baeldung.crypto.utils.CryptoUtils;
+
+public class BadPaddingExamples {
+
+    public static byte[] encryptAndDecryptUsingDifferentKeys(byte[] plainTextBytes)
+            throws InvalidKeyException, GeneralSecurityException {
+        SecretKey encryptionKey = CryptoUtils.getKeyForText("BaeldungIsASuperCoolSite");
+        SecretKey differentKey = CryptoUtils.getKeyForText("ThisGivesUsAnAlternative");
+
+        Cipher cipher = Cipher.getInstance("AES/ECB/ISO10126Padding");
+
+        cipher.init(Cipher.ENCRYPT_MODE, encryptionKey);
+        byte[] cipherTextBytes = cipher.doFinal(plainTextBytes);
+
+        cipher.init(Cipher.DECRYPT_MODE, differentKey);
+
+        return cipher.doFinal(cipherTextBytes);
+    }
+
+    public static byte[] encryptAndDecryptUsingDifferentAlgorithms(SecretKey key, IvParameterSpec ivParameterSpec,
+            byte[] plainTextBytes) throws InvalidKeyException, GeneralSecurityException {
+        Cipher cipher = Cipher.getInstance("AES/CBC/ISO10126Padding");
+
+        cipher.init(Cipher.ENCRYPT_MODE, key, ivParameterSpec);
+        byte[] cipherTextBytes = cipher.doFinal(plainTextBytes);
+
+        cipher = Cipher.getInstance("AES/ECB/ISO10126Padding");
+
+        cipher.init(Cipher.DECRYPT_MODE, key);
+
+        return cipher.doFinal(cipherTextBytes);
+    }
+
+    public static byte[] encryptAndDecryptUsingDifferentPaddings(SecretKey key, byte[] plainTextBytes)
+            throws InvalidKeyException, GeneralSecurityException {
+        Cipher cipher = Cipher.getInstance("AES/ECB/ISO10126Padding");
+        cipher.init(Cipher.ENCRYPT_MODE, key);
+        byte[] cipherTextBytes = cipher.doFinal(plainTextBytes);
+
+        cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
+        cipher.init(Cipher.DECRYPT_MODE, key);
+
+        return cipher.doFinal(cipherTextBytes);
+    }
+
+    public static byte[] encryptAndDecryptUsingSamePaddingKeyAndAlgorithm(SecretKey key, byte[] plainTextBytes)
+            throws InvalidKeyException, GeneralSecurityException {
+        Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
+        cipher.init(Cipher.ENCRYPT_MODE, key);
+        byte[] cipherTextBytes = cipher.doFinal(plainTextBytes);
+
+        cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
+        cipher.init(Cipher.DECRYPT_MODE, key);
+
+        return cipher.doFinal(cipherTextBytes);
+    }
+}

core-java-modules/core-java-security-3/src/main/java/com/baeldung/crypto/exception/IllegalBlockSizeExamples.java

@@ -0,0 +1,32 @@
+package com.baeldung.crypto.exception;
+
+import java.security.InvalidKeyException;
+import java.security.NoSuchAlgorithmException;
+
+import javax.crypto.BadPaddingException;
+import javax.crypto.Cipher;
+import javax.crypto.IllegalBlockSizeException;
+import javax.crypto.NoSuchPaddingException;
+import javax.crypto.SecretKey;
+
+import com.baeldung.crypto.utils.CryptoUtils;
+
+public class IllegalBlockSizeExamples {
+
+    public static byte[] encryptWithoutPadding(SecretKey key, byte[] plainTextBytes) throws NoSuchAlgorithmException,
+            NoSuchPaddingException, InvalidKeyException, BadPaddingException, IllegalBlockSizeException {
+        Cipher cipher = Cipher.getInstance("AES/ECB/NoPadding");
+        cipher.init(Cipher.ENCRYPT_MODE, key);
+
+        return cipher.doFinal(plainTextBytes);
+    }
+
+    public static byte[] decryptTextThatIsNotEncrypted(SecretKey key) throws NoSuchAlgorithmException,
+            NoSuchPaddingException, InvalidKeyException, BadPaddingException, IllegalBlockSizeException {
+        // note that this text is not encrypted at any point in this method.
+        String sampleText = "https://www.baeldung.com/";
+        byte[] unencryptedCipherTextBytes = sampleText.getBytes();
+
+        return CryptoUtils.decryptWithPadding(key, unencryptedCipherTextBytes);
+    }
+}

core-java-modules/core-java-security-3/src/main/java/com/baeldung/crypto/exception/InvalidAlgorithmParameterExamples.java

@@ -0,0 +1,23 @@
+package com.baeldung.crypto.exception;
+
+import java.security.GeneralSecurityException;
+import java.security.InvalidKeyException;
+
+import javax.crypto.Cipher;
+import javax.crypto.SecretKey;
+import javax.crypto.spec.IvParameterSpec;
+
+public class InvalidAlgorithmParameterExamples {
+
+    public static byte[] encryptUsingIv(SecretKey key, byte[] ivBytes, String plainText)
+            throws InvalidKeyException, GeneralSecurityException {
+        IvParameterSpec ivParameterSpec = new IvParameterSpec(ivBytes);
+
+        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
+        cipher.init(Cipher.ENCRYPT_MODE, key, ivParameterSpec);
+
+        byte[] bytes = plainText.getBytes();
+
+        return cipher.doFinal(bytes);
+    }
+}

core-java-modules/core-java-security-3/src/main/java/com/baeldung/crypto/exception/InvalidKeyExamples.java

@@ -0,0 +1,56 @@
+package com.baeldung.crypto.exception;
+
+import java.security.GeneralSecurityException;
+import java.security.InvalidKeyException;
+
+import javax.crypto.Cipher;
+import javax.crypto.SecretKey;
+import javax.crypto.spec.IvParameterSpec;
+
+import com.baeldung.crypto.utils.CryptoUtils;
+
+public class InvalidKeyExamples {
+
+    public static byte[] decryptUsingCBCWithNoIV(SecretKey key, byte[] cipherTextBytes)
+            throws InvalidKeyException, GeneralSecurityException {
+        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
+        cipher.init(Cipher.DECRYPT_MODE, key);
+
+        return cipher.doFinal(cipherTextBytes);
+    }
+
+    public static byte[] decryptUsingCBCWithIV(SecretKey key, byte[] cipherTextBytes)
+            throws InvalidKeyException, GeneralSecurityException {
+        byte[] ivBytes = new byte[] { 'B', 'a', 'e', 'l', 'd', 'u', 'n', 'g', 'I', 's', 'G', 'r', 'e', 'a', 't', '!' };
+        IvParameterSpec ivParameterSpec = new IvParameterSpec(ivBytes);
+
+        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
+        cipher.init(Cipher.DECRYPT_MODE, key, ivParameterSpec);
+
+        return cipher.doFinal(cipherTextBytes);
+    }
+
+    public static byte[] encryptWithKeyTooShort() throws InvalidKeyException, GeneralSecurityException {
+        SecretKey encryptionKey = CryptoUtils.getKeyForText("ThisIsTooShort");
+
+        String plainText = "https://www.baeldung.com/";
+        byte[] bytes = plainText.getBytes();
+
+        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
+
+        cipher.init(Cipher.ENCRYPT_MODE, encryptionKey);
+        return cipher.doFinal(bytes);
+    }
+
+    public static byte[] encryptWithKeyTooLong() throws InvalidKeyException, GeneralSecurityException {
+        SecretKey encryptionKey = CryptoUtils.getKeyForText("ThisTextIsTooLong");
+
+        String plainText = "https://www.baeldung.com/";
+        byte[] bytes = plainText.getBytes();
+
+        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
+
+        cipher.init(Cipher.ENCRYPT_MODE, encryptionKey);
+        return cipher.doFinal(bytes);
+    }
+}

core-java-modules/core-java-security-3/src/main/java/com/baeldung/crypto/exception/NoSuchAlgorithmExamples.java

@@ -0,0 +1,29 @@
+package com.baeldung.crypto.exception;
+
+import java.security.NoSuchAlgorithmException;
+
+import javax.crypto.Cipher;
+import javax.crypto.NoSuchPaddingException;
+
+public class NoSuchAlgorithmExamples {
+
+    public static Cipher getCipherInstanceWithBadAlgorithm()
+            throws NoSuchAlgorithmException, NoSuchPaddingException {
+        return Cipher.getInstance("ABC");
+    }
+
+    public static Cipher getCipherInstanceWithBadAlgorithmMode()
+            throws NoSuchAlgorithmException, NoSuchPaddingException {
+        return Cipher.getInstance("AES/ABC");
+    }
+
+    public static Cipher getCipherInstanceWithBadPadding()
+            throws NoSuchAlgorithmException, NoSuchPaddingException {
+        return Cipher.getInstance("AES/CBC/ABC");
+    }
+
+    public static Cipher getCipherInstanceWithValidAlgorithm()
+            throws NoSuchAlgorithmException, NoSuchPaddingException {
+        return Cipher.getInstance("AES/CBC/PKCS5Padding");
+    }
+}

core-java-modules/core-java-security-3/src/main/java/com/baeldung/crypto/utils/CryptoUtils.java

@@ -1,16 +1,21 @@
 package com.baeldung.crypto.utils;
 
+import java.nio.charset.StandardCharsets;
 import java.security.AlgorithmParameters;
 import java.security.GeneralSecurityException;
+import java.security.InvalidKeyException;
 import java.security.NoSuchAlgorithmException;
 import java.security.SecureRandom;
 import java.security.spec.InvalidParameterSpecException;
 
+import javax.crypto.BadPaddingException;
 import javax.crypto.Cipher;
+import javax.crypto.IllegalBlockSizeException;
 import javax.crypto.KeyGenerator;
 import javax.crypto.NoSuchPaddingException;
 import javax.crypto.SecretKey;
 import javax.crypto.spec.IvParameterSpec;
+import javax.crypto.spec.SecretKeySpec;
 
 public class CryptoUtils {
 
@@ -20,6 +25,21 @@ public class CryptoUtils {
         return keyGenerator.generateKey();
     }
 
+    public static SecretKey getKeyForText(String secretText) throws GeneralSecurityException {
+        byte[] keyBytes = secretText.getBytes(StandardCharsets.UTF_8);
+        return new SecretKeySpec(keyBytes, "AES");
+    }
+
+    /*
+     * Allows us to generate a deterministic key, for the purposes of producing
+     * reliable and consistent demo code & tests! For a random key, consider using
+     * the generateKey method above.
+     */
+    public static SecretKey getFixedKey() throws GeneralSecurityException {
+        String secretText = "BaeldungIsASuperCoolSite";
+        return getKeyForText(secretText);
+    }
+
     public static IvParameterSpec getIV() {
         SecureRandom secureRandom = new SecureRandom();
         byte[] iv = new byte[128 / 8];
@@ -29,18 +49,17 @@ public class CryptoUtils {
         return new IvParameterSpec(nonce);
     }
 
-    public static IvParameterSpec getIVSecureRandom(String algorithm) throws NoSuchAlgorithmException, NoSuchPaddingException {
+    public static IvParameterSpec getIVSecureRandom(String algorithm)
+            throws NoSuchAlgorithmException, NoSuchPaddingException {
         SecureRandom random = SecureRandom.getInstanceStrong();
-        byte[] iv = new byte[Cipher.getInstance(algorithm)
-            .getBlockSize()];
+        byte[] iv = new byte[Cipher.getInstance(algorithm).getBlockSize()];
         random.nextBytes(iv);
         return new IvParameterSpec(iv);
     }
 
     public static IvParameterSpec getIVInternal(Cipher cipher) throws InvalidParameterSpecException {
         AlgorithmParameters params = cipher.getParameters();
-        byte[] iv = params.getParameterSpec(IvParameterSpec.class)
-            .getIV();
+        byte[] iv = params.getParameterSpec(IvParameterSpec.class).getIV();
         return new IvParameterSpec(iv);
     }
 
@@ -50,4 +69,20 @@ public class CryptoUtils {
         return nonce;
     }
 
+    public static byte[] encryptWithPadding(SecretKey key, byte[] bytes) throws NoSuchAlgorithmException,
+            NoSuchPaddingException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException {
+        Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
+        cipher.init(Cipher.ENCRYPT_MODE, key);
+
+        byte[] cipherTextBytes = cipher.doFinal(bytes);
+        return cipherTextBytes;
+    }
+
+    public static byte[] decryptWithPadding(SecretKey key, byte[] cipherTextBytes) throws NoSuchAlgorithmException,
+            NoSuchPaddingException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException {
+        Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
+        cipher.init(Cipher.DECRYPT_MODE, key);
+
+        return cipher.doFinal(cipherTextBytes);
+    }
 }

core-java-modules/core-java-security-3/src/test/java/com/baeldung/crypto/exception/BadPaddingExamplesUnitTest.java

@@ -0,0 +1,61 @@
+package com.baeldung.crypto.exception;
+
+import java.security.GeneralSecurityException;
+
+import javax.crypto.BadPaddingException;
+import javax.crypto.SecretKey;
+import javax.crypto.spec.IvParameterSpec;
+
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+
+import com.baeldung.crypto.utils.CryptoUtils;
+
+public class BadPaddingExamplesUnitTest {
+
+    private SecretKey key;
+    private IvParameterSpec ivParameterSpec;
+    private String plainText;
+    private byte[] plainTextBytes;
+
+    @Before
+    public void before() throws GeneralSecurityException {
+        key = CryptoUtils.getFixedKey();
+
+        byte[] ivBytes = new byte[] { 'B', 'a', 'e', 'l', 'd', 'u', 'n', 'g', 'I', 's', 'G', 'r', 'e', 'a', 't', '!' };
+        ivParameterSpec = new IvParameterSpec(ivBytes);
+
+        plainText = "https://www.baeldung.com/";
+        plainTextBytes = plainText.getBytes();
+    }
+
+    @Test
+    public void givenTwoDifferentAlgorithmPaddings_whenDecrypting_thenBadPaddingExceptionIsThrown()
+            throws GeneralSecurityException {
+        Assert.assertThrows(BadPaddingException.class,
+                () -> BadPaddingExamples.encryptAndDecryptUsingDifferentPaddings(key, plainTextBytes));
+    }
+
+    @Test
+    public void givenTwoDifferentKeys_whenDecrypting_thenBadPaddingExceptionIsThrown() throws GeneralSecurityException {
+        Assert.assertThrows(BadPaddingException.class,
+                () -> BadPaddingExamples.encryptAndDecryptUsingDifferentKeys(plainTextBytes));
+    }
+
+    @Test
+    public void givenTwoDifferentAlgorithms_whenDecrypting_thenBadPaddingExceptionIsThrown()
+            throws GeneralSecurityException {
+        Assert.assertThrows(BadPaddingException.class, () -> BadPaddingExamples
+                .encryptAndDecryptUsingDifferentAlgorithms(key, ivParameterSpec, plainTextBytes));
+    }
+
+    @Test
+    public void givenSameVariablesUsedForEncryptingAndDecrypting_whenDecrypting_thenNoExceptionIsThrown()
+            throws GeneralSecurityException {
+        byte[] decryptedBytes = BadPaddingExamples.encryptAndDecryptUsingSamePaddingKeyAndAlgorithm(key,
+                plainTextBytes);
+
+        Assert.assertEquals(plainText, new String(decryptedBytes));
+    }
+}

core-java-modules/core-java-security-3/src/test/java/com/baeldung/crypto/exception/IllegalBlockSizeExamplesUnitTest.java

@@ -0,0 +1,56 @@
+package com.baeldung.crypto.exception;
+
+import java.security.GeneralSecurityException;
+import java.security.InvalidKeyException;
+import java.security.NoSuchAlgorithmException;
+
+import javax.crypto.BadPaddingException;
+import javax.crypto.IllegalBlockSizeException;
+import javax.crypto.NoSuchPaddingException;
+import javax.crypto.SecretKey;
+
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+
+import com.baeldung.crypto.utils.CryptoUtils;
+
+public class IllegalBlockSizeExamplesUnitTest {
+
+    private SecretKey key;
+    private byte[] plainTextBytes;
+    private String plainText;
+
+    @Before
+    public void before() throws GeneralSecurityException {
+        key = CryptoUtils.getFixedKey();
+
+        plainText = "https://www.baeldung.com/";
+        plainTextBytes = plainText.getBytes();
+    }
+
+    @Test
+    public void whenEncryptingPlainTextWithoutPadding_thenIllegalBlockSizeExceptionIsThrown()
+            throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, IllegalBlockSizeException,
+            BadPaddingException {
+        Assert.assertThrows(IllegalBlockSizeException.class,
+                () -> IllegalBlockSizeExamples.encryptWithoutPadding(key, plainTextBytes));
+    }
+
+    @Test
+    public void whenDecryptingCipherTextThatWasNotEncrypted_thenIllegalBlockSizeExceptionIsThrown()
+            throws GeneralSecurityException {
+        Assert.assertThrows(IllegalBlockSizeException.class,
+                () -> IllegalBlockSizeExamples.decryptTextThatIsNotEncrypted(key));
+    }
+
+    @Test
+    public void whenEncryptingAndDecryptingWithPadding_thenNoExceptionThrown() throws NoSuchAlgorithmException,
+            NoSuchPaddingException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException {
+        byte[] cipherTextBytes = CryptoUtils.encryptWithPadding(key, plainTextBytes);
+
+        byte[] decryptedBytes = CryptoUtils.decryptWithPadding(key, cipherTextBytes);
+
+        Assert.assertEquals(plainText, new String(decryptedBytes));
+    }
+}

core-java-modules/core-java-security-3/src/test/java/com/baeldung/crypto/exception/InvalidAlgorithmParameterExamplesUnitTest.java

@@ -0,0 +1,59 @@
+package com.baeldung.crypto.exception;
+
+import java.security.GeneralSecurityException;
+import java.security.InvalidAlgorithmParameterException;
+
+import javax.crypto.Cipher;
+import javax.crypto.SecretKey;
+import javax.crypto.spec.IvParameterSpec;
+
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+
+import com.baeldung.crypto.utils.CryptoUtils;
+
+public class InvalidAlgorithmParameterExamplesUnitTest {
+
+    private SecretKey key;
+    private String plainText;
+
+    @Before
+    public void before() throws GeneralSecurityException {
+        key = CryptoUtils.getFixedKey();
+
+        plainText = "https://www.baeldung.com/";
+    }
+
+    @Test
+    public void givenIvIsTooShort_whenEncryptingUsingCBC_thenInvalidAlgorithmParameterExceptionIsThrown()
+            throws GeneralSecurityException {
+        byte[] ivBytes = new byte[] { 'B', 'a', 'e', 'l', 'd', 'u', 'n', 'g', 'I', 's', 'G', 'r', 'e', 'a', 't' };
+        Assert.assertThrows(InvalidAlgorithmParameterException.class,
+                () -> InvalidAlgorithmParameterExamples.encryptUsingIv(key, ivBytes, plainText));
+    }
+
+    @Test
+    public void givenIvIsTooLong_whenEncryptingUsingCBC_thenInvalidAlgorithmParameterExceptionIsThrown()
+            throws GeneralSecurityException {
+        byte[] ivBytes = new byte[] { 'B', 'a', 'e', 'l', 'd', 'u', 'n', 'g', 'I', 's', 'G', 'r', 'e', 'a', 't', '!',
+                '?' };
+        Assert.assertThrows(InvalidAlgorithmParameterException.class,
+                () -> InvalidAlgorithmParameterExamples.encryptUsingIv(key, ivBytes, plainText));
+    }
+
+    @Test
+    public void givenIvIsCorrectSize_whenEncryptingUsingCBC_thenNoExceptionIsThrown() throws GeneralSecurityException {
+        byte[] ivBytes = new byte[] { 'B', 'a', 'e', 'l', 'd', 'u', 'n', 'g', 'I', 's', 'G', 'r', 'e', 'a', 't', '!' };
+        byte[] cipherTextBytes = InvalidAlgorithmParameterExamples.encryptUsingIv(key, ivBytes, plainText);
+
+        IvParameterSpec ivParameterSpec = new IvParameterSpec(ivBytes);
+
+        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
+        cipher.init(Cipher.DECRYPT_MODE, key, ivParameterSpec);
+
+        byte[] decryptedBytes = cipher.doFinal(cipherTextBytes);
+
+        Assert.assertEquals(plainText, new String(decryptedBytes));
+    }
+}

core-java-modules/core-java-security-3/src/test/java/com/baeldung/crypto/exception/InvalidKeyExamplesUnitTest.java

@@ -0,0 +1,62 @@
+package com.baeldung.crypto.exception;
+
+import java.security.GeneralSecurityException;
+import java.security.InvalidKeyException;
+
+import javax.crypto.Cipher;
+import javax.crypto.SecretKey;
+import javax.crypto.spec.IvParameterSpec;
+
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+
+import com.baeldung.crypto.utils.CryptoUtils;
+
+public class InvalidKeyExamplesUnitTest {
+
+    private SecretKey key;
+    private String plainText;
+    private byte[] cipherTextBytes;
+
+    @Before
+    public void before() throws GeneralSecurityException {
+        key = CryptoUtils.getFixedKey();
+
+        byte[] ivBytes = new byte[] { 'B', 'a', 'e', 'l', 'd', 'u', 'n', 'g', 'I', 's', 'G', 'r', 'e', 'a', 't', '!' };
+        IvParameterSpec ivParameterSpec = new IvParameterSpec(ivBytes);
+
+        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
+        cipher.init(Cipher.ENCRYPT_MODE, key, ivParameterSpec);
+
+        plainText = "https://www.baeldung.com/";
+        byte[] plainTextBytes = plainText.getBytes();
+
+        cipherTextBytes = cipher.doFinal(plainTextBytes);
+    }
+
+    @Test
+    public void givenTextEncryptedWithCBC_whenDecryptingWithNoIv_thenInvalidKeyExceptionIsThrown() {
+        Assert.assertThrows(InvalidKeyException.class,
+                () -> InvalidKeyExamples.decryptUsingCBCWithNoIV(key, cipherTextBytes));
+    }
+
+    @Test
+    public void givenTextEncryptedWithCBC_whenDecryptingWithIv_thenTextIsDecrypted()
+            throws InvalidKeyException, GeneralSecurityException {
+        byte[] decryptedBytes = InvalidKeyExamples.decryptUsingCBCWithIV(key, cipherTextBytes);
+
+        Assert.assertEquals(plainText, new String(decryptedBytes));
+    }
+
+    @Test
+    public void whenKeyIsTooShort_thenInvalidKeyExceptionIsThrown() {
+        Assert.assertThrows(InvalidKeyException.class, () -> InvalidKeyExamples.encryptWithKeyTooShort());
+    }
+
+    @Test
+    public void whenKeyIsTooLong_thenInvalidKeyExceptionIsThrown() {
+        Assert.assertThrows(InvalidKeyException.class, () -> InvalidKeyExamples.encryptWithKeyTooLong());
+    }
+
+}

core-java-modules/core-java-security-3/src/test/java/com/baeldung/crypto/exception/NoSuchAlgorithmExamplesUnitTest.java

@@ -0,0 +1,38 @@
+package com.baeldung.crypto.exception;
+
+import java.security.GeneralSecurityException;
+import java.security.NoSuchAlgorithmException;
+
+import javax.crypto.Cipher;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+public class NoSuchAlgorithmExamplesUnitTest {
+
+    @Test
+    public void whenInitingCipherWithUnknownAlgorithm_thenNoSuchAlgorithmExceptionIsThrown()
+            throws GeneralSecurityException {
+        Assert.assertThrows(NoSuchAlgorithmException.class,
+                () -> NoSuchAlgorithmExamples.getCipherInstanceWithBadAlgorithm());
+    }
+
+    @Test
+    public void whenInitingCipherWithUnknownAlgorithmMode_thenNoSuchAlgorithmExceptionIsThrown()
+            throws GeneralSecurityException {
+        Assert.assertThrows(NoSuchAlgorithmException.class,
+                () -> NoSuchAlgorithmExamples.getCipherInstanceWithBadAlgorithmMode());
+    }
+
+    @Test
+    public void whenInitingCipherWithUnknownPadding_thenNoSuchAlgorithmExceptionIsThrown()
+            throws GeneralSecurityException {
+        Assert.assertThrows(NoSuchAlgorithmException.class,
+                () -> NoSuchAlgorithmExamples.getCipherInstanceWithBadPadding());
+    }
+
+    @Test
+    public void whenInitingCipherWithValidAlgorithm_thenCipherInstanceIsReturned() throws GeneralSecurityException {
+        Assert.assertTrue(NoSuchAlgorithmExamples.getCipherInstanceWithValidAlgorithm() instanceof Cipher);
+    }
+}