public static void main(String[] args) throws Exception {
//
// check args and get plaintext
if (args.length != 1) {
System.err.println("Usage: java MessageAuthenticationCodeExample text");
System.exit(1);
}
byte[] plainText = args[0].getBytes("UTF8");
//
// get a key for the HmacMD5 algorithm
System.out.println("\nStart generating key");
KeyGenerator keyGen = KeyGenerator.getInstance("HmacMD5");
SecretKey MD5key = keyGen.generateKey();
System.out.println("Finish generating key");
//
// get a MAC object and update it with the plaintext
Mac mac = Mac.getInstance("HmacMD5");
mac.init(MD5key);
mac.update(plainText);
//
// print out the provider used and the MAC
System.out.println("\n" + mac.getProvider().getInfo());
System.out.println("\nMAC: ");
System.out.println(new String(mac.doFinal(), "UTF8"));
}
