A 6 minute
introduction to
homomorphic
encryption
Introduction
Encryption has been around for thousands of years, used across the ages to send secret messages to one another. For example the Caesar cipher, which consists of simply swapping letters in the alphabet, is one of the earliest encryption techniques, dating back to 60BC!
With the advent of the internet, the amount of private data we generate has increased exponentially — and with it a massive rise in data breaches and mass surveillance. In response we’ve invented new encryption techniques, culminating in the mainstream adoption of end to end encryption in our everyday apps.
But how does end to end encryption actually work? And how will it change the way we use the internet?
How your data is protected today
The reason our data is still being stolen is because it isn't encrypted during processing.
Data theft is growing at an unprecedented rate — we need end to end encryption now more than ever.
Introducing: Homomorphic Encryption
Fully Homomorphic Encryption — or FHE for short — is a technology that enables processing data without decrypting it. This means companies can offer their services without ever seeing their users’ data — and users will never notice a difference in functionality.
With data encrypted both in transit and during processing, everything we do online could now be encrypted end to end, not just sending messages!
How it works
Let’s have a look at how FHE works by applying a filter to an encrypted image.
Step 1: Pick one of your favourite pictures
Step 1: Pick one of your favourite pictures
Upload one of your favorite pictures to see how you can apply a filter while keeping it encrypted.
Step 2: Create a unique password to encrypt your picture
Step 2: Create a unique password to encrypt your picture
By encrypting your picture with a secret password, you ensure the owner of the cloud service cannot see it while processing it.
Step 3: Apply a filter to your encrypted picture
Step 3: Apply a filter to your encrypted picture
Applying a filter on your encrypted picture will result in another encrypted picture. Random pixels in, random pixels out!
Step 4: Enter your password again to decrypt the result
Step 4: Enter your password again to decrypt the result
By decrypting the result using the same password that encrypted the original picture, you get the actual picture with the filters applied to it!
What just happened?
This is the power of homomorphic encryption! You just used an online service without revealing any of your personal data.
From your point of view, the service hasn’t changed: you sent a photo to the cloud and applied a filter to it. But from the cloud's point of view, everything was encrypted — no company, government or hacker could ever see your data!
How FHE will change the future
Preventive Medicine
Imagine knowing in advance what you need to do to stay healthy throughout your life. This is increasingly possible with AI, but requires sharing all your health data — everything from your DNA, to your medical history, to your lifestyle habits. With FHE, you could send all this data while keeping it encrypted, and the AI would respond with encrypted health recommendations that you alone have the ability to see.
Facial Recognition
From science fiction to the palm of your hand, facial recognition is now a part of our everyday experience. We use facial recognition to enter buildings, to unlock our phones, to tag people in pictures and soon to login to websites everywhere. This however requires someone to have your biometric fingerprint, which in the wrong hands can be used to impersonate you. With FHE, you could authenticate yourself securely, without anybody being able to steal your biometric data.
Voice
Every time your family speaks to a voice assistant, they send personal information to the companies behind them, increasing the risk that someone can steal this data. With FHE, you could send encrypted voice queries to AI assistants, who would have no way of knowing what you just asked, while still being able to respond. It wouldn’t matter that you have a microphone in your house, because nobody would be able to listen to what you say!
How FHE will change the Internet
When the internet first appeared, we accessed websites via an HTTP address. Nothing was encrypted, and anybody could listen to what you sent online. Then came HTTPS, which encrypts data in transit. We believe FHE will enable a new internet protocol, HTTPZ, where everything is encrypted end to end. Privacy wouldn't matter anymore, not because it isn't important, but because it would be guaranteed by design in the internet itself!
WANT TO SEE FHE IN ACTION?
We are a team of cryptographers and engineers passionate about privacy. We build open source FHE technologies to help companies make their products encrypted end to end. Our hope is to one day see this HTTPZ vision come to life, so that we can put an end to mass surveillance and data breaches!
