System and method for massive controlled and secured update of devices firmware

System for securely updating a firmware of a mail processing device from a remote data server comprising:

• file download servers connected to the remote data server for receiving from the remote data server encrypted files encrypted from a list of binary files corresponding to a firmware of the mail processing device to update,
• web servers providing a web service application for downloading files and connected both to the remote data server and the files download servers for retrieving the encrypted files associated with a personalized files catalogue retrieved from the remote data server, and
• a user computer system connected to the web servers for receiving the encrypted files for download onto a mass storage device to plug into the mail processing device,
• the mail processing device decrypting the encrypted files with file decryption keys previously provided with the personalized files catalogue by the remote data server and installing the files before connecting to the remote data server for report the outcome of the installation.