A Social Distanced Santa Sends Secure Presents
It seems like a lifetime away, but I remember the time when there was great debate about the track-and-trace method. So while most of the world went for a decentralised approach, the English system used a centralised method — Integrated Encryption Scheme (IES). It made sense for the as the NHS as it used a public key for the track and trace system and a random value on the phone, and then encrypted a contact. The NHS — with their private key — were then able to decrypt this. It thus used good old public key and secret key encrytion — a hybrid encryption scheme. So, as it’s as it’s nearly Christmas, let’s have a crypto Christmas.
Santa needs to send presents securely
Well, because of social distancing, Santa can’t deliver presents this year, so he’ll have to send them electronically. So how does Santa (Alice) send a secret present to a child (Bob)? Well, Santa’s little Elves have been prototyping two forms of IES: discrete logs and elliptic curve.
As part of the Elve’s research they found that IES is a hybrid encryption scheme which allows Santa (Alice) to get Bob’s public key, and then generate an encryption key based on Bob’s public key and Santa’s private key. Initially Bob and Santa (Alice) agree on a generate value (g) and a prime number (p). The elves setup each person with a…