Use node crypto instead of sjcl

LICENSE

@@ -402,39 +402,6 @@
    Library.
 
 
-   sjcl
-   --------------------
-   License: BSD
-
-   http://opensource.org/licenses/BSD-2-Clause
-
-   Copyright (c) 2009-2015, Emily Stark, Mike Hamburg and Dan Boneh at
-   Stanford University. All rights reserved.
-
-   Redistribution and use in source and binary forms, with or without
-   modification, are permitted provided that the following conditions are
-   met:
-
-   1. Redistributions of source code must retain the above copyright
-   notice, this list of conditions and the following disclaimer.
-
-   2. Redistributions in binary form must reproduce the above copyright
-   notice, this list of conditions and the following disclaimer in the
-   documentation and/or other materials provided with the distribution.
-
-   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
-   IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
-   TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
-   PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-   HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
-   TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
-   PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
-   LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
-   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
-   SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-
-
    window
    --------------------
    License: MIT

lib/FetchRequest.js

@@ -1,5 +1,5 @@
 const fetch = require('make-fetch-happen');
-const sjcl = require("sjcl");
+const crypto = require("crypto");
 const URL = require('url').URL;
 
 function FetchRequest(param) {
@@ -91,8 +91,7 @@ function FetchRequest(param) {
     }
 
     let signMessage = function(messageString) {
-        let hmacFunction = new sjcl.misc.hmac(sjcl.codec.utf8String.toBits(myself.apiKeySecret), sjcl.hash.sha256);// Key, Hash
-        return sjcl.codec.hex.fromBits(hmacFunction.encrypt(messageString));
+        return crypto.createHmac('sha256', myself.apiKeySecret).update(messageString).digest('hex');
     }
 }