Encryption with AES-256 Java

Question

I have this simple code, that i found on the internet.. im learning this stuff of encryption/decryption.. this code seems to work fine, but i don't understand something... why after the "c.doFinal()" (which is for encrypt/decrypt with AES-256) this guy encode/decode that encrypted value, with BASE64? its not enough only by using AES?

`private static final String ALGO = "AES";
 private static final byte[] keyValue = 
 new byte[] { 'T', 'h', 'e', 'B', 'e', 's', 't', 'S', 'e', 'c', 'r','e', 't', 'K', 'e', 'y' };


 public static String encrypt(String Data) throws Exception {
    Key key = generateKey();
    Cipher c = Cipher.getInstance("AES");
    c.init(Cipher.ENCRYPT_MODE, key);
    byte[] encVal = c.doFinal(Data.getBytes());
    String encryptedValue = new BASE64Encoder().encode(encVal);
    return encryptedValue;
}

public static String decrypt(String encryptedData) throws Exception {
    Key key = generateKey();
    Cipher c = Cipher.getInstance(ALGO);
    c.init(Cipher.DECRYPT_MODE, key);
    byte[] decordedValue = new BASE64Decoder().decodeBuffer(encryptedData);
    byte[] decValue = c.doFinal(decordedValue);
    String decryptedValue = new String(decValue);
    return decryptedValue;
}
private static Key generateKey() throws Exception {
    Key key = new SecretKeySpec(keyValue, ALGO);
    return key;
}

public static void main(String[] args) throws Exception {

    String data = "SOME TEXT";
    String dataEnc = AES.encrypt(data);
    String dataDec = AES.decrypt(dataEnc);

    System.out.println("Plain Text : " + data);
    System.out.println("Encrypted Text : " + dataEnc);
    System.out.println("Decrypted Text : " + dataDec);
}`

Thanks!!

This is actually using 128-bit AES, not 256. The key is 16 bytes; 16 bytes * 8 bits per byte = 128 bit key. — daiscog

Syon Syon · Accepted Answer · 2013-08-21T16:00:33

The encrypted data returned by doFinal is binary, and so it cannot be printed (it'll appear as a bunch of gibberish.) The Base64 encoding converts the binary to a set of ASCII characters, this makes it easily readable and also makes it possible to use the encrypted data in situations where only plaintext data can be used.

The Base64 encoding doesn't add any extra encryption or security, it simply makes the encrypted data usable in situations where you can't use binary.

Encryption with AES-256 Java

3 Answers