If you are attempting to use this service, here is what the workflow usually looks like:
The server creates a QR code image file (usually in PNG or SVG format) that contains the encrypted data. This image is what you see printed on your physical NID card or displayed on your screen.
When you request a copy of your NID (via the official portal services.nidw.gov.bd ), your NID number is sent to the server. The server queries the central database of the Bangladesh Election Commission.