15.3.2. Prerequisites: OpenSSL and the clock

Two pieces have to be in place before any of the hands-on pages will work: the OpenSSL command-line tool on your development machine, and a correct clock on the camera at the moment of every TLS handshake.

15.3.2.1. Installing OpenSSL

The commands in this section use the openssl command-line tool, run on your development machine – not on the camera. It is often already installed; check with:

openssl version

If it is missing, install it for your operating system:

  • Linux – use the package manager, e.g. sudo apt install openssl (Debian/Ubuntu), sudo dnf install openssl (Fedora/RHEL) or sudo pacman -S openssl (Arch).

  • macOS – brew install openssl using Homebrew.

  • Windows – install a build such as Win32/Win64 OpenSSL, use a package manager (winget install ShiningLight.OpenSSL.Light or choco install openssl), or use the openssl that ships with Git for Windows (run it from Git Bash).

15.3.2.2. Setting the clock

ssl.CERT_REQUIRED checks each certificate’s validity period, so the camera’s clock must be correct or verification fails (a freshly powered-up camera has no idea what time it is). With a working network connection, the ntptime module fetches the time over NTP and sets the on-board RTC (machine.RTC), in UTC:

import ntptime

ntptime.settime()                 # query NTP and set machine.RTC (UTC)

After this, time.localtime() and machine.RTC reflect the current UTC time. Bringing the network interface up is board-specific and is not shown here; the examples on the following pages assume the camera is already connected.