Learn How Encryption Works

We’ve mentioned encryption and its impact on your privacy and security in other guides and guidebooks, but what exactly is it, and how does it protect us?

The definition of encryption is ‘the process of converting information or data into a code, to prevent unauthorised access’. To better understand encryption it’s worth taking a moment to learn about its origins, how it’s been developed over the years and how it applies to our modern communications.

The word encryption comes from the ancient Greek word Kryptos, which means hidden or secret. Interestingly, the use of hiding messages from others can be traced back to early Egyptian scribes who inserted non-standard hieroglyphs within other communications in order to hide the message from casual viewers. According to historians the Spartans used strips of leather with messages engraved. When the strips were read they were meaningless but when wrapped around a staff of a certain diameter the characters would be decipherable.

Of course, the modern forms of encryption are far more advanced but the overall core concept has remained the same: to be able to send a message to others without anyone else being able to decipher it. However, modern encryption now requires more than simply sending coded messages. Not only is confidentiality required, encryption must perform a level of authentication, so the origin of the communication can be verified; integrity of the communications, where both the sender and those who receive the communication can be ensured that the message hasn’t been altered in between; and some form of nonrepudiation, where the sender cannot deny having sent the communication in the first place.

During the early digital age the only users of encryption were the government and military, and as such between them they created a set of algorithms and standards to protect the communication on the battlefield and from one government agency to the next. These algorithms grew in complexity as technology advanced and it wasn’t long before the military-based forms of encryption were being used in commercial modes of communications. Within a few short years, bank transfers, cash withdrawals and data sent to and from modems began utilising these new protocols to protect sensitive information.


Today we’re regularly seeing and using devices that boast ‘military grade 256-bit AES’ forms of encryption, a standard that is regarded as nearly impossible to break without spending billions on specialist hardware and software. In plain English, the modern form of encryption takes data and passes it through an algorithm together with a key. This creates a garbled file of characters that can only be clearly read if the correct key is applied to decrypt the data. Algorithms today are divided into two categories: symmetric and asymmetric.

Symmetric key ciphers use the same key to both encrypt and decrypt data. The most popular symmetric cipher is AES (Advanced Encryption Standard), developed by the military and government to protect communications and data. This is a fast form of decryption that requires the sender to exchange the key used to encrypt the data with the recipient before they’re able to read it.

Asymmetric key ciphers are also known as public-key cryptography and utilise two mathematically linked keys, public and private. The public key can be shared with everyone and is usually generated by software or provided by a designated authority. The private key is something that’s usually only known by the individual user. Interestingly both types of keys can be applied, where one user has a public key and another a private key, which can be combined to form a shared encryption level.

These keys are many characters in length, proving it nigh impossible for someone to Brute Force hack them. The Brute Force method involves using a program on a computer to try every possible combination of a key until the correct one is found. In the case of the 256-bit encryption, it would take an unbelievably huge number of different combinations to break the key.

If you were able to force one trillion key combinations per second, it would still take you somewhere in the region of 1057 years in order to crack 256-bit encryption (that’s 1 followed by 57 zeros). However, a powerful computer can probably manage around two billion calculations per second, so in theory it would take 9.250 years for your standard desktop to crack it. Take in mind that the universe has theoretically only been in existence for 1.410 years.

Numbers as big as that are generally far too mind-boggling to comprehend. Suffice to say that if you’re able to use 256-bit encryption for your communications or to protect your data, then you’re going to be protected for at least seven times the current age of the universe.

David Hayward

David has spent most of his life tinkering with technology, from the ZX Spectrum, getting his hands on a Fujitsu VPP5000/100 supercomputer, and coding on an overheating Raspberry Pi. He's written for the likes of Micro Mart, Den of Geek, and countless retro sites and publications, covering reviews, creating code and bench testing the latest tech. He also has a huge collection of cables.

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