It’s Not Witchcraft It’s Maths

Homomorphic encryption is coming to the mass market.

Dateline: Woking, 13th March 2025.

Apple, boldly proclaiming that it believes privacy is a fundamental human right, has announced the use of “homomorphic encryption” in its products. This means that a client device (e.g., an iPhone) encrypts a query before sending it to a server (e.g., Apple), then the server operates on the encrypted query and generates an encrypted response, which the client then decrypts. The server does not decrypt the query or even have access to the decryption key, so the client data remains private throughout the process.

Witchcraft Or Math?

I realise that to a lot of people, including regulators and legislators, that must sound like witchcraft but it is actually a tried and tested cryptographic method that has many applications and a crucial role to play in the future online economy. So let’s get into it.