In this article, I’ll go over all you need to know about cryptography.

Cryptography is a security mechanism that is used in almost every application, from your phone to bank cards and iPod.

Far from it, blockchain technology, in general, relies heavily on cryptography for a variety of reasons.

But what are these reasons, and why are they so important in blockchain technology?

That is the question I seek to address in this post. Let’s get started!

Post Summary

I will cover the following:

1. What is Cryptography? – A Brief History
2. Concept of Cryptography
3. How Does Cryptography Work?
4. Types of Cryptography
5. Which Cryptography Does The Blockchain Use?
6. FAQs
7. Conclusion

I promise to make this article as non-techy as possible. Let’s dive in!

What is Cryptography? – A Brief History

Cryptography is the use of codes to securely transmit information.

It is the process of converting plaintext into a secret language such that a third party other than the recipient cannot infiltrate it.

To explain the meaning of cryptography, let’s use this classroom scenario:

Suppose your teacher asks a question and invites you to the front of the class to present the answer.

Unfortunately, you do not know the answer and want to seek assistance from your friend who is seated just in front of the teacher.

What if you write him a secret code that looks like this: “RTUC ?AHMA NEHN SRE WNWLY EEIPO” which he alone understands, rather than “Can you help me with the answer?”

Now, that makes sense, right? Because there is definitely no way that the teacher will know what you have written.

Now, let’s take a trip down the history lane of cryptography. Scroll down!

A Brief History Of Cryptography

The term “cryptography” is derived from two Greek words, “Krypto➙ Secret or Hidden” and “Graphene➙ Writing”.

It simply translates to Secret Writing.

Cryptography originated thousands of years ago, right from the time of classic cryptography, which involved concealing messages with handwriting.

During the times of antiquity, cryptography was widely used to protect sensitive information.

Notably, it is found in non-standard hieroglyphics engraved in the tomb of a great Egyptian monarch, Khnumhotep, according to archives.

In approximately 1500 BC, the people of Mesopotamia used cryptography to conceal the recipe for commercially valuable pottery glaze.

Also, Julius Ceaser was known for communicating with his governors through cryptography to keep traitors at bay during the Roman Empire.

The contemporary use of cryptography began in the 20th century with the emergence of mechanical machines, the most renowned was the Enigma machine.

Over the years, cryptography has advanced since the invention of computers – from DES in 1970 to AES in 2001, which is also current as of 2021.

Today, cryptography has also made the use of cryptocurrencies possible.

And it is primarily used to protect the security of data recorded on the blockchain and to authenticate transactions. Impressive!

Now, It should be noted that cryptography has a long history of development that was not covered in this article.

However, you can read a thorough history of cryptography right here in this article.

Scroll down to the next section!

Concept of Cryptography

Cryptography basically consists of these 5 concepts:

i. Plaintext

This is the original data that the sender wishes to convey.

It’s written in understandable characters, example “John is back, you can come to the house tomorrow.”

ii. Cipher

Cipher is a cryptographic algorithm that converts plaintexts to ciphertexts.

Ciphertext is complete gibberish that can’t be deciphered unless you have the right access to translate it into plaintext.

The analogy I created in the previous section contains an example of a ciphertext.

Cipher has existed since time immemorial and has continued to evolve; you can learn more about the various types of cipher here.

iii. Encryption

Encryption is the process of converting text into ciphertext.

Citing our analogy this time again, you encrypted the message to your classroom friend by converting it into a secret text.

iv. Decryption

 This is the opposite of encryption.

It is the process of transforming encrypted information or Cipher text into its original format (plaintext). 

v. Key

The key is a fundamental aspect of cryptography.

It is an algorithm for encrypting and decrypting secret messages.

So, how do we put these 5 concepts to work in cryptography? Scroll down and I will tell you how.

How Does Cryptography Work?

I’d like to use this second analogy to demonstrate how cryptography works in lay terms:

Assuming we have two business partners, Tolu and Uche, who have concluded a transaction and want to communicate privately about it.

Tolu wants to notify Uche that he has deposited $1000 into his account using a public medium, say, the internet.

They are both aware, however, that the internet is insecure.

And therefore, a third party, such as their rival, Agha, may exploit their message by modifying or intercepting it.

For example, Agha may try to change the message to “You are the worst business partner ever,” and that would be disastrous if it happened.

Now, to avoid this, they decide to use cryptography to deliver their messages.

And this is exactly the point where the different concepts of cryptography which we have discussed above come into play.

So this is how cryptography works:

– Tolu encrypts his message with a private key. (In the graphic above, Tolu’s message is represented by P, and the key by Ke.)

– When the message is encrypted, the result will be a ciphertext (we have it in the image as C).

– This ciphertext will be transferred via the internet, and rather than the original text, Agha will get the ciphertext.

– At the end, when the ciphertext reaches Uche, he will decrypt (D) the ciphertext using his private key (KD) to obtain the original message.

And that is how cryptography basically works.

We currently have two types of cryptography, which I will discuss below. Scroll down and read on!

Types of Cryptography

The 2 types of cryptography are:

• Symmetric Key Cryptography
• Asymmetric Key Cryptography

Symmetric Key Cryptography

Symmetric cryptography is an encryption system in which the sender and receiver share a single key, and it is used for both encryption and decryption.

It uses this formular: Ke (encryption key) = Kd (decryption key).

By using this cryptography, encrypted messages can not be understood by anyone who does not have the secret key to decrypt it.

For example, in our second example, if Tolu and Uche use this type of cryptography, it means they share the same private key.

Asymmetric Key Cryptography

Asymmetric cryptography is also called Public-Key Cryptography.

It uses the formula Ke (encryption key) ❌ Kd (decryption key).

This simply means that the encryption key is different from the decryption key.

Also, this cryptography uses a pair of keys, one of which is known as the public key and the other as the private key.

While the public key is known and can be broadcasted on the network, the private key is kept confidential.

For example, instead of sharing the same private key as Uche, Tolu can encrypt his message using Uche’s public key.

When it is sent over the internet, Agha will only see Uche’s public key and nothing else and, for the decryption, only Uche has the right key to decrypt it.

After reading this, you may be wondering what type of cryptography is used by the blockchain, bitcoin, and other cryptocurrencies.

Don’t worry, I’ll go over it in more details below, so keep scrolling.

Which Cryptography Does The Blockchain Use?

Rather than securing messages, cryptography secures transactions that are performed on the blockchain.

Asymmetric cryptography is the cryptography used by blockchains and cryptocurrencies.

Moreover, it is well known that cryptocurrencies have two kinds of keys:

• Public Key: Also known as the wallet address, is publicly available to everyone on the network and is used to receive funds and send cryptocurrencies.
• Private Key: This is a secret key that is used to authenticate transactions when spending cryptocurrency.

When creating asymmetric keys, several mathematical algorithms can be used.

However, the Elliptic Curve Digital Signature Algorithm is used by cryptocurrencies such as BTC and ETH.

The blockchain network also employs a cryptographic feature known as the hash function to keep its network secure.

A hash function is a cryptographic algorithm that converts any length input to a fixed-length output.

One thing to note about the hash function is that, once it converts plaintext to ciphertext, decryption becomes almost impossible.

The hash function, for instance, ensures the following;

• Immutability of the blockchain network.
• It is also used to generate cryptocurrency public and private keys.
• The private key is combined with the hash function to generate digital signatures for spending cryptos.
• The hash function also serves as the foundation for Bitcoin mining.

More information on the Hash function may be found here.

I addressed some of the most often asked blockchain cryptography questions.

You’ll find them if you scroll down.

FAQs

P.S

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Conclusion

This brings us to the end of the article for today!

As previously said, cryptography is ideal since it gives the sender total assurance that his message will only be accessed by the receiver.

I hope you’ve prepared a comprehensive note about cryptography.

So, please tell me:

How would you explain cryptography in your own words?

What are your opinions on quantum computers, and do you feel they will be the blockchain’s undoing?

Is there anything I’ve missed in this post?

Leave your views in the comments section below, and I’ll answer.

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