Hello! I've read your documents and came up with a low price for a large system. I have all the skills necessary to cover your requirements. I plan to use CodeIgniter (PHP) as the back-end framework, MySQL for the database, and JavaScript for the front-end scripting. I know all the steps needed for security, such as hashing, sessions, privileges. My experience in a large system was in my corporate work at HP where I developed a tool that would survey the users, track their results, and report it through charts and Excel. Communication between us won't be a problem, I'm fluent in English. My past clients loved me, and you will too! Please feel free to contact me for any inquires/request. I hope to hear from you again, thank you for reading my bid.