Basic symmetric encryption example : Symmetric Encryption « Security « Java Tutorial


import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;

public class MainClass {
  public static void main(String[] args) throws Exception {
    Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider());
    byte[] input = "input123".getBytes();
    byte[]        keyBytes = new byte[] {
        0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
        0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f };

    SecretKeySpec key = new SecretKeySpec(keyBytes, "AES");
    Cipher cipher = Cipher.getInstance("AES/ECB/NoPadding", "BC");

    byte[] cipherText = new byte[input.length];
    cipher.init(Cipher.ENCRYPT_MODE, key);
    int ctLength = cipher.update(input, 0, input.length, cipherText, 0);

    ctLength += cipher.doFinal(cipherText, ctLength);

    System.out.println("cipher text: " + new String(cipherText) + " bytes: " + ctLength);

    byte[] plainText = new byte[ctLength];

    cipher.init(Cipher.DECRYPT_MODE, key);

    int ptLength = cipher.update(cipherText, 0, ctLength, plainText, 0);

    ptLength += cipher.doFinal(plainText, ptLength);

    System.out.println("plain text : " + new String(plainText) + " bytes: " + ptLength);

36.46.Symmetric Encryption
36.46.1.Basic symmetric encryption example
36.46.2.Basic symmetric encryption example with padding
36.46.3.Basic symmetric encryption example with padding and ECB using DES
36.46.4.Basic symmetric encryption example with padding and CBC using DES
36.46.5.Symmetric encryption example with padding and CBC using DES with the initialization vector inline.