Modify a JavaScript freeware adding a few options

The Script: Already freeware here [login to view URL] The Issue: Download link after file encryption is in base64 url (too long) and cant handle file size greater than 1 MB (can see comments on the link pasted above). Requirement: Need the script modified to handle files greater than 1MB and add a few optional checkboxes where user can choose other encryption methods (right now its default is AES ) by including other .js libraries (possibly if you know of another more secure open source encryption library) Note: Please read the whole article and comments on that page to get a better idea on what you are working on. thanks. The script does Javascript encryption client side WITHOUT user needing to send file to server.