Hey SN,
If you happen to be in Paris this evening, we're having the second edition of our Parisian BitDevs in French. Mode details (including location and time) on this Telegram channel: https://t.me/BitdevsFR.
Satishi Nakamoto came up with mining via hashing. Due to hashfunctions unique properties (1.collision resistance 2.preimage resistance 3.secind preimage resistance) the security of the Blockchain can be derived from the raw computing power. This is what we call ”proof of work”