code: private SessionTicketKey deriveKeyFromSeed(String seed) {
          byte[] seedBin = decodeHex(seed);
          byte[] keyName = hkdf(seedBin, salt, NAME_BYTES, SessionTicketKey.NAME_SIZE);
          byte[] aesKey = hkdf(seedBin, salt, AES_BYTES, SessionTicketKey.AES_KEY_SIZE);
          byte[] hmacKey = hkdf(seedBin, salt, HMAC_BYTES, SessionTicketKey.HMAC_KEY_SIZE);
          return new SessionTicketKey(keyName, hmacKey, aesKey);
      }
docs: Derives a {@link SessionTicketKey} from the given ticket seed using the {@link CryptoUtil#hkdf} function.
  
  @param seed the ticket seed.
  @return the ticket key.