public function createHash($data) {
        $string = $this->recursiveHash($data);
        $secret = $this->getClientSignSecret();
        return self::base64UrlEncode(hash_hmac("sha256", $string, $secret, true));
    }
public function createHash($data) {
        $string = $this->recursiveHash($data);
        $secret = $this->getClientSignSecret();
        return self::base64UrlEncode(hash_hmac("sha256", $string, $secret, true));
    }
public function createHash ( $ data ) { $ string = $ this -> recursiveHash ( $ data ) ; $ secret = $ this -> getClientSignSecret ( ) ; return self :: base64UrlEncode ( hash_hmac ( "sha256" , $ string , $ secret , true ) ) ; }
Creates a post data array hash that must be added to outgoing API requests
that require it.

@param  array $data
@return  string
Creates a post data array hash that must be added to outgoing API requests that require it .