Simple String Encryption in Java for Barcode Security

General Discussions
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1

What is the simplest way to encrypt a string in Java so that it appears unreadable when scanned from a 2D barcode (PDF-417)? I don’t need anything overly complex—no RSA, PKI infrastructure, or key pairs—just a straightforward Java encryption method that deters casual snooping while remaining easy to decrypt for authorized companies. Ideally, it should follow a standard approach that isn’t tied to a specific platform or technology.

Is there a Java class that provides encrypt() and decrypt() functions without requiring high-security setups? What would be the best approach for this?

2

If you want something widely used and standard, AES (Advanced Encryption Standard) is a great option for java encryption. It’s easy to implement, secure enough to deter casual snooping, and compatible across different platforms.

Here’s a simple AES encryption & decryption example in Java:

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import java.util.Base64;

public class SimpleAESEncryption {
    private static SecretKey secretKey;

    static {
        try {
            KeyGenerator keyGenerator = KeyGenerator.getInstance("AES");
            keyGenerator.init(128);
            secretKey = keyGenerator.generateKey();
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    public static String encrypt(String data) throws Exception {
        Cipher cipher = Cipher.getInstance("AES");
        cipher.init(Cipher.ENCRYPT_MODE, secretKey);
        return Base64.getEncoder().encodeToString(cipher.doFinal(data.getBytes()));
    }

    public static String decrypt(String encryptedData) throws Exception {
        Cipher cipher = Cipher.getInstance("AES");
        cipher.init(Cipher.DECRYPT_MODE, secretKey);
        return new String(cipher.doFinal(Base64.getDecoder().decode(encryptedData)));
    }

    public static void main(String[] args) throws Exception {
        String original = "Hello, World!";
        String encrypted = encrypt(original);
        String decrypted = decrypt(encrypted);

        System.out.println("Original: " + original);
        System.out.println("Encrypted: " + encrypted);
        System.out.println("Decrypted: " + decrypted);
    }
}

:small_blue_diamond: Why use AES for java encryption?

  • Easy to implement with built-in Java libraries.
  • Widely accepted standard, so it works across different technologies.
  • Simple encryption & decryption using a single key.
3

While AES is a robust choice, if you just need basic obfuscation (not high security), XOR encryption could be a lighter option. It’s a great fit for cases where you want to obscure the data without the complexity of AES. It’s not secure for high-risk environments but can be useful for casual protection.

Here’s an example of how you can implement XOR-based java encryption:

public class XOREncryption {
    private static final String KEY = "simplekey"; // Keep it secret

    public static String encryptDecrypt(String input) {
        char[] key = KEY.toCharArray();
        char[] data = input.toCharArray();
        char[] output = new char[data.length];

        for (int i = 0; i < data.length; i++) {
            output[i] = (char) (data[i] ^ key[i % key.length]);
        }
        return new String(output);
    }

    public static void main(String[] args) {
        String original = "Hello, World!";
        String encrypted = encryptDecrypt(original);
        String decrypted = encryptDecrypt(encrypted);

        System.out.println("Original: " + original);
        System.out.println("Encrypted: " + encrypted);
        System.out.println("Decrypted: " + decrypted);
    }
}

:small_blue_diamond: Why use XOR encryption for java encryption?

  • Super lightweight—no external libraries needed.
  • Easy to implement and decrypt.
  • Not very secure, but good for obfuscation when high security is not required.

:bulb: If you don’t need strong security but just want to make text unreadable, this is the simplest approach.

4

If your goal is not encryption but simply to hide the text in a way that deters casual observation (especially in something like a 2D barcode), you might consider Base64 encoding. It’s quick and easy, though it’s not true encryption. It simply makes the text appear garbled and obfuscated.

Here’s an example using Base64 encoding in java encryption:

import java.util.Base64;

public class Base64Example {
    public static String encrypt(String data) {
        return Base64.getEncoder().encodeToString(data.getBytes());
    }

    public static String decrypt(String encryptedData) {
        return new String(Base64.getDecoder().decode(encryptedData));
    }

    public static void main(String[] args) {
        String original = "Hello, World!";
        String encrypted = encrypt(original);
        String decrypted = decrypt(encrypted);

        System.out.println("Original: " + original);
        System.out.println("Encrypted: " + encrypted);
        System.out.println("Decrypted: " + decrypted);
    }
}

:small_blue_diamond: Why use Base64 encoding in java encryption?

  • Fastest method for hiding text.
  • Easy to decode, so authorized companies can retrieve the data.
  • Not encryption, but simply an encoding method that makes text unreadable in scans.