Windows – Copying windows shared folder files on unix into Unix

I am on a unix box with Sun OS 5.0. Now I have a shared folder on a Windows server on my LAN. I have some files on Windows to be copied into my unix by running a script on unix itself. So windows box will not push any thing on its own and only unix has to copy from there.

I used FTP and it is successfully working. But is there any possible way which does not require FTP and you can directly copy from the windows shared folder as we do in windows to windows copying. I am asking this because we feel FTP is slower for the size of data we have to copy and history tells it is not so secure. I am ready to install and try tools on unix but my organization doesnt allow to install on windows server. If any tool which can be installed on Windows and adds value then I am ready to convince my authorities.

Please advice on any tools or methods which can be used for this cross platform copying which can make it fast. I tried googling but donno which tool will be faster.