code: private final void encrypt() throws Exception {
          String signStr = Base64Coder.toString(Base64Coder.base64Encode(signature));
          String ud = userData.toString();
  
          if (TraceComponent.isAnyTracingEnabled() && tc.isEventEnabled()) {
              Tr.event(this, tc, "encrypt: userData" + ud);
          }
  
          byte[] accessID = Base64Coder.getBytes(ud);
          StringBuilder sb = new StringBuilder(DELIM);
          sb.append(getExpiration()).append(DELIM).append(signStr);
          byte[] timeAndSign = getSimpleBytes(sb.toString());
          byte[] toBeEnc = new byte[accessID.length + timeAndSign.length];
          for (int i = 0; i < accessID.length; i++) {
              toBeEnc[i] = accessID[i];
          }
          for (int i = accessID.length; i < toBeEnc.length; i++) {
              toBeEnc[i] = timeAndSign[i - accessID.length];
          }
          try {
              encryptedBytes = LTPAKeyUtil.encrypt(toBeEnc, sharedKey, cipher);
          } catch (Exception e) {
              if (TraceComponent.isAnyTracingEnabled() && tc.isEventEnabled()) {
                  Tr.event(this, tc, "Error encrypting; " + e);
              }
              throw e;
          }
  
          if (TraceComponent.isAnyTracingEnabled() && tc.isEventEnabled()) {
              Tr.event(this, tc, "Encrypted bytes are: " + (encryptedBytes == null ? "" : Base64Coder.toString(Base64Coder.base64Encode(encryptedBytes))));
          }
      }
docs: Encrypt the token passed into the token.
  
  @throws TokenException