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What is encryption? 5 types of encryptions explained

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Intrusion Detection System: Benefits, types and modes of operation

Encryption, as we know it today, is embedded in everything. From your WhatsApp messages to your bank account, any data that is exchanged between two terminals on the internet needs to be encrypted.

What is encryption? When was it born? How does it work and why such a dire need for it? Read on to find out.

History of Encryption

Cryptography, the art of using codes to communicate has been around for thousands of years. In computers, however, it only evolved in the early 20th century.

During World War II, various countries came up with different technologies to encrypt their communications to avoid them being intercepted and read by the enemy.

In modern times, we use stronger, more reliable digital encryption algorithms to protect our data on the internet. The mid-1970s saw two significant public advances.

Number one being a draft on Data Encryption Standard published in the U.S Federal Register on 17th March 1975. This was a DES cipher which was proposed by a team of researchers working at IBM. These researchers were trying to come up with secure data communication facilities for large financial organisations such as banks.

The second development was another publication in 1976. This was a paper named ‘New Directions in Cryptography’ and was written by Whitfield Diffie and Martin Hellman. This paper fundamentally changed the way cryptosystems work by introducing a completely new method of distributing cryptographic keys.

It revolutionised the way cryptographic keys were distributed, which solved an age-old problem in cryptography – key distribution.

This article also caused an almost immediate and completely public development of a new class of data encryption algorithms which are now known as asymmetric algorithms. Before the release of this paper, all encryption systems were based on symmetric key systems which made them easier to crack.

Also read: Why is Cyber Security important? 5 tips to protect yourself

How does modern encryption work?

Encryption, in a nutshell, is a technology that converts a message or a file into an unreadable entity so that it cannot be read or accessed by any third party.

This is done using computer algorithms that generate keys to encrypt and decrypt data. The size of these keys, usually measured in bits, determines how secure is the encryption. The most common encryption algorithms offer somewhere between 128 to 256-bit key encryption.

Types of Encryption

What is encryption? 5 types of encryptions explained

The main purpose of encryption is to protect digital data confidentiality as it travels from one device to another on the internet. Encryption is mainly classified as Symmetric Encryption, Asymmetric Encryption and Hashing.

The major difference between symmetric and asymmetric key ciphers is that symmetric key ciphers use one unique key to encrypt or decrypt the file whereas asymmetric ciphers use a unique public key for encrypting and another private key for decrypting data.

Hashing, on the other hand, refers to converting a string of characters into fixed length values or key that represent the original string.

To achieve this, various data encryption algorithms are used. Each one has its unique characteristics and applications. Here we go over five of the most commonly used ones in the recent times.

Triple DES

Triple DES was designed to replace the original DES encryption algorithm after hackers were able to crack the latter with ease.  During its time of relevance, it was the recommended standard and the most commonly symmetric key algorithm.

Triple DES works using three individual keys which are 56 bits each. This makes the total key length a total of 168 bits. However,  experts say that you should expect only about 112-bit encryption.

While triple DES still manages to be a reliable hardware encryption system for some institutions, it’s being phased out in favour of some more advanced algorithms.


RSA (Rivest–Shamir–Adleman) is a public-key encryption algorithm and has become the standard for encrypting data sent over the internet. It is also widely used in PGP and GPG programs. It usually offers a 1024-bit key.

RSA is an asymmetric algorithm as it uses a pair of keys. This means that there is a public key, which we use to encrypt our data and a private key to decrypt it. Which means anyone can encrypt data, but only one authority can decrypt it.

RSA essentially creates a huge unreadable mess of the file you’ve encrypted. Hackers face a lot of trouble decrypting it as it needs a lot of computing power and time to crack.

Don’t be fooled by the 1024-bit key size though as it can be cracked relatively easily. RSA claims that 2048-bit keys should be sufficient until 2030. An RSA key length of 3072 bits is suggested if security is required beyond 2030.

Also read: If Google says a website isn’t secure, what does it really mean?

MD5 Hashing

The MD5 message-digest algorithm is a widely used hash function. It produces a 128-bit hash value.

It was initially designed to be used as a cryptographic hash function. After being put to use in the field, it was found to have serious security issues.

When using MD5, it takes very less computational power to find the common hash between two encrypted files. You could even decrypt it on your home computer!

That’s why MD5 is now used to check file integrity but only against unintentional corruption.


Twofish was built as the successor to another encryption algorithm known as Blowfish. It uses keys up to 256-bit in strength and is asymmetric technique.

Twofish is considered as one of the fastest among its class. It is also viable for both software and hardware environments. It is also freely available to everyone. Which is why you’ll see quite a lot of freeware using this.

The best part about it? There are no known attacks on it. The closest thing to decrypting the algorithm is a couple of theoretical attacks, and even they haven’t gone too far.


The Advanced Encryption Standard (AES) is the algorithm used as a standard by the U.S government and various other organisations.

It is a very efficient encrypting algorithm with keys usually of 128-bit. For heavy-duty applications 192 and 256-bit keys are also used.

Similar to Twofish, AES also has no known attacks that can crack it. The sole exception being brute-force attacks. These attacks attempt all possible key combinations of 128,192 and 256 bits until they find the right key.

Keep in mind though, that this requires a substantial amount of computing power and not to mention, patience.

Also read: What is a VPN and 5 other questions answered