1) If it was terrorism, since there have been no claims of responsibility, it was a proof-of-concept attack for a broader attack. I’d thought of some new sort of bomb that could be brought past security, but a software attack on the avionics would also fit.
2) Again *if* it was terrorism, Al Qaeda—their Algerian branch is a continuation of the Algerian Islamist movement that grew out of the anti-colonialist (anti-French) rebellion.
3) See 1).
But if it was a bomb, the results would be immediate and catastrophic..not a systematic shutdown of computer systems, IMHO..