diff --git a/core-java-modules/core-java-security-algorithms/src/test/java/com/baeldung/blowfish/BlowFishUnitTest.java b/core-java-modules/core-java-security-algorithms/src/test/java/com/baeldung/blowfish/BlowFishUnitTest.java
new file mode 100644
index 0000000000..5b5a3b2055
--- /dev/null
+++ b/core-java-modules/core-java-security-algorithms/src/test/java/com/baeldung/blowfish/BlowFishUnitTest.java
@@ -0,0 +1,92 @@
+package com.baeldung.blowfish;
+
+import java.io.BufferedReader;
+import java.io.BufferedWriter;
+import java.io.FileOutputStream;
+import java.io.FileReader;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.Base64;
+
+import javax.crypto.Cipher;
+import javax.crypto.spec.SecretKeySpec;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+class BlowFishUnitTest {
+
+    @Test
+    public void givenBlowfishAlogrithm_whenEncryptAndDecryptString_thenCompareResults() throws Exception {
+        String secretMessage = "Secret message to encrypt";
+        String secretKey = "MyKey123";
+        byte[] keyData = secretKey.getBytes();
+
+        // Encryption
+        SecretKeySpec secretKeySpec = new SecretKeySpec(keyData, "Blowfish");
+        Cipher encryptCipher = Cipher.getInstance("Blowfish");
+        encryptCipher.init(Cipher.ENCRYPT_MODE, secretKeySpec);
+        byte[] encryptedBytes = encryptCipher.doFinal(secretMessage.getBytes(StandardCharsets.UTF_8));
+        String encryptedtext = Base64.getEncoder().encodeToString(encryptedBytes);
+
+        // Decryption
+        byte[] ecryptedtexttobytes = Base64.getDecoder().decode(encryptedtext);
+        Cipher decryptCipher = Cipher.getInstance("Blowfish");
+        decryptCipher.init(Cipher.DECRYPT_MODE, secretKeySpec);
+        byte[] decrypted = decryptCipher.doFinal(ecryptedtexttobytes);
+        String decrypedText = new String(decrypted, StandardCharsets.UTF_8);
+
+        Assertions.assertEquals(secretMessage, decrypedText);
+    }
+
+    @Test
+    public void givenBlowfishAlogrithm_whenEncryptAndDecryptFile_thenCompareResults() throws Exception {
+        String secretKey = "MyKey123";
+        byte[] keyData = secretKey.getBytes();
+        SecretKeySpec secretKeySpec = new SecretKeySpec(keyData, "Blowfish");
+
+        String originalContent = "some secret text file";
+        Path tempFile = Files.createTempFile("temp", "txt");
+        writeFile(tempFile, originalContent);
+
+        // Encryption
+        byte[] fileBytes = Files.readAllBytes(tempFile);
+        Cipher encryptCipher = Cipher.getInstance("Blowfish");
+        encryptCipher.init(Cipher.ENCRYPT_MODE, secretKeySpec);
+        byte[] encryptedFileBytes = encryptCipher.doFinal(fileBytes);
+        try (FileOutputStream stream = new FileOutputStream(tempFile.toFile())) {
+            stream.write(encryptedFileBytes);
+        }
+
+        // Decryption
+        encryptedFileBytes = Files.readAllBytes(tempFile);
+        Cipher decryptCipher = Cipher.getInstance("Blowfish");
+        decryptCipher.init(Cipher.DECRYPT_MODE, secretKeySpec);
+        byte[] decryptedFileBytes = decryptCipher.doFinal(encryptedFileBytes);
+        try (FileOutputStream stream = new FileOutputStream(tempFile.toFile())) {
+            stream.write(decryptedFileBytes);
+        }
+
+        String fileContent = readFile(tempFile);
+
+        Assertions.assertEquals(originalContent, fileContent);
+    }
+
+    private void writeFile(Path path, String content) throws Exception {
+        try (BufferedWriter writer = Files.newBufferedWriter(path)) {
+            writer.write(content);
+        }
+    }
+
+    private String readFile(Path path) throws Exception {
+        StringBuilder resultStringBuilder = new StringBuilder();
+        try (BufferedReader br = new BufferedReader(new FileReader(path.toFile()))) {
+            String line;
+            while ((line = br.readLine()) != null) {
+                resultStringBuilder.append(line);
+            }
+        }
+        return resultStringBuilder.toString();
+    }
+}