src/Gateways/CitrusGateway.php
protected function encrypt()
    {

        $hash_string = $this->vanityUrl.$this->parameters['orderAmount'].$this->parameters['merchantTxnId'].$this->parameters['currency'];

        $this->hash = hash_hmac('sha1', $hash_string, $this->secretKey);

    }
protected function encrypt()
    {

        $hash_string = $this->vanityUrl.$this->parameters['orderAmount'].$this->parameters['merchantTxnId'].$this->parameters['currency'];

        $this->hash = hash_hmac('sha1', $hash_string, $this->secretKey);

    }
Citrus Encrypt Function