Submit form to download software

Our website wants to implement a php form that users complete, which then lets them download some software, get emailed a license key and inserts their record into a MySQL database. My proposed pseudo code is as follows: function to santize cleanup input data function to generate a key based on an algorithm (for the purposes of this project, returning a fixed string of '01234567890' is fine) function to insert firstname, surname, company, email, newsletter optin? and key into database function to send email if (action=='submit') { ? ? ? ? cleanup the data to protect against SQL injection and bad characters and error check for format ? ? ? ? generatekey ? ? ? ? insert into database ? ? ? ? sendemail to customer ? ? ? ? show a "thankyou page" ? ? ? ? autodownload the executable } else { ? ? ? ? < form> ? ? ? ? ? ? ? ? First Name: text ? ? ? ? ? ? ? ? Last Name: text ? ? ? ? ? ? ? ? Company: text ? ? ? ? ? ? ? ? Email Address: text ? ? ? ? ? ? ? ? Newsletter: checkbox ? ? ? ? < / form> }