Encryption is nothing new: cryptographic messages that needed special tools to be decoded date back to ancient times. But the age of electronic communications and the widespread use of encrypted messaging apps has led to a new debate on the technology’s safety – and whether it should be allowed.
Encrypted communications are everywhere on the internet, from online banking to secure website connections to WhatsApp and iMessage. But the technology has also been criticised for allowing terrorists to communicate secretly, plotting attacks in safety that wouldn’t have been possible when they communicated by post or telephone.
What is encryption?
Fundamentally, encryption is the act of scrambling communication to stop people other than its intended recipient from reading it.
In various forms, the technique dates back millennia – Julius Caesar used basic encryption in messages to his generals – but modern warfare saw its use expanded. British codebreaking decryption of encrypted Nazi messages was seen as one of the defining moments in the war.
In the late 1960s the British intelligence organisation GCHQ started to develop the system of modern computer cryptography that is widely used today to secure online transactions and messages.
A decent analogy for encryption is the digital version of sending something in a locked safe. Only those with the right key can get in.
So what’s end-to-end encryption?
Encryption just means that communication is scrambled in some way. A message could still be encrypted and deciphered by the third party – a government or tech company – if they had a way to unlock it.
End-to-end encryption, on the other hand, means that a message is encoded in such a way that only the sender and receiver can see it.
To go back to the safe analogy, encryption simply means the safe is locked – someone with a key could get in. End-to-end encryption means nobody apart from the sender and receiver can open the safe.
Messaging apps such as WhatsApp and Signal now apply end-to-end encryption so that although messages may travel over their servers, they cannot read them even if they wanted to.
How does encryption work?
When you send a message to a recipient on WhatsApp, your app encodes it using a special key that can only be unlocked by the recipient. The actual process of encrypting the message is a complicated series of digital handshakes but all you need to know is that it is near-impossible to crack.
A fresh set of keys and locks is produced whenever two phones communicate, making the process safe each time.