Generating a Message Authentication Code (MAC)
A MAC is like hash code for a sequence of bytes. Unlike a hash code,
a MAC uses a secret key to generate the hash code, or more
specifically, the message digest. A MAC is generally used to
check the integrity or validity of information based on a secret key.
try {
// Generate a key for the HMAC-MD5 keyed-hashing algorithm; see RFC 2104
// In practice, you would save this key.
KeyGenerator keyGen = KeyGenerator.getInstance("HmacMD5");
SecretKey key = keyGen.generateKey();
// Create a MAC object using HMAC-MD5 and initialize with key
Mac mac = Mac.getInstance(key.getAlgorithm());
mac.init(key);
String str = "This message will be digested";
// Encode the string into bytes using utf-8 and digest it
byte[] utf8 = str.getBytes("UTF8");
byte[] digest = mac.doFinal(utf8);
// If desired, convert the digest into a string
String digestB64 = new sun.misc.BASE64Encoder().encode(digest);
} catch (InvalidKeyException e) {
} catch (NoSuchAlgorithmException e) {
} catch (UnsupportedEncodingException e) {
}
Post a comment