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A Brief History of Cryptography

By Laurel Tincher · April 09, 2021 · 6 minute read

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A Brief History of Cryptography

Who doesn’t love a good secret code? Cryptography is the science of secret codes—of creating a language or code that can’t be cracked unless one knows exactly how to decode it.

Today, cryptography is used for everything from internet cybersecurity to blockchain technology and cryptocurrency investing. It has evolved and advanced over time along with technology, but it got its start in ancient times, with hieroglyphs and cuneiforms.

Let’s look back at the history of cryptography and how it has evolved over the years to serve different functions with the same goal—securing information.

What is Cryptography?

Cryptography is the process of securing information by changing it into a form that people can’t understand unless they know how it was encoded. The original information is known as plaintext, and the encoded version of the information is known as ciphertext. The calculation or code used to change plaintext into ciphertext is called an algorithm and the process is called encryption. The opposite of encryption is decryption—turning ciphertext back into plaintext, or another readable form.

In order for someone to decode the information, they need to know how to read it or change it back into its plaintext form. Usually decryption involves both the algorithm and a key. Generally this key is a number.

Ancient History of Cryptography

The history of encryption dates back thousands of years. The earliest known use of cryptography was over 5600 years ago in Sumeria and Egypt. Cuneiform and hieroglyphics were created to record transactions. These were not necessarily intended to be secret, but were forms of writing down information that someone wouldn’t know how to read unless they understood the language system. It took hundreds of years for these early forms of writing to be deciphered by other societies.

Early forms of encryption all used a key that had to be given to the recipient in order for them to be able to decipher it. This is known as symmetric encryption, because the same key is used for encryption and decryption. The following are several examples of ciphers that use symmetric encryption.

Caesar Box

Julius Caesar used cryptography around 100 BC to send messages to his military generals, encrypted to be protected from opponents who might intercept it. The “Caesar Box,” or “Caesar Cipher,” was easily decrypted by those who knew how, but it protected messages from unintended eyes.

The Caesar Cipher is what is known as a “substitution cipher” or “shift cipher.” It works by changing each letter within a message three letters, to the right. For example, an A in a message would become a D, and a B would be written as an E. The number of letter places that get shifted is called the key. In this case the key is three.

Since there are only 26 letters in the English alphabet, shift ciphers like the Caesar Box are easy to figure out and not very secure forms of cryptography. Once mathematicians figured out that certain letters are more commonly used than others in a language, they understood that people trying to crack the code could start to recognize patterns and figure it out.

Scytale Cipher

The Spartans developed a different type of encryption known as the Scytale Cipher. It was made by wrapping parchment around a pole then writing on the pole length-wise. When the paper is removed from the pole, the message is encrypted. To decipher it, one needs to know the pole’s diameter. The Scytale is less easy to decipher using patterns like the Caesar Box, but it can be possible to read some of the words on the pole.

Vigenère Cipher

The Vigenère Cipher was created by an Italian named Giovan Battista Bellaso in the 16th century. It uses a key as part of the decryption process. The key can be any combination of letters or a word of the message writer’s choosing. The key is matched to the plaintext and used in the process of decrypting the secret message. It’s much more difficult than the Caesar Box because each letter of the message has its own shift value. Therefore, even solving one word in the message won’t reveal the entire message.

Using a key adds an extra layer of security to a cryptographic message. The cipher wasn’t solved until 1863, and became known as le chiffre indechiffrable, or “the indecipherable cipher.”

Vernam Cipher

The only cipher that has been mathematically proven to be unbreakable is the Vernam Cipher, otherwise known as a one-time pad (OTP). It’s similar to a Vigenere Cipher but the key changes with each use. The Vernam Cipher isn’t used widely today due to the challenges of distributing the keys, but it is useful for emergency situations in which there is no electronic option.


The Enigma is a type of cryptography using rotary encryption, which was developed by Arthur Scherbius in Germany during WWII. Similar to other cryptography, it was created using disks that were put into a machine in a certain order. If they were inserted in the correct order, the machine would decode the message.

An early computer developed by British cryptanalyst Alan Turing and his colleagues helped to crack the Enigma code. It’s estimated that their work helped save as many as 21 million people.

Asymmetric Encryption and Modern Cryptography

The advent of computers made it essential to develop more advanced forms of cryptography in order to keep data and information safe. This was especially the case as financial transactions began to move to computer networks. Everything from email to ecommerce sites to phone apps use encryption today.

The world of cryptography is also getting more complex due to its use by terrorists and criminals, as well as legal structures which protect individuals’ data. The U.S. Government and tech companies like Apple have been in legal battles for years to determine the ethics around data and privacy.

Most modern cryptography uses asymmetric encryption, or public-key encryption, in which there is a separate lock and key. This allows people to share public keys openly while keeping the private keys secure.

Here are some examples of asymmetric encryption.

Morse Code

Samuel F. Morse developed the Morse Code to transmit messages through telegraph machines in 1835.

The Zimmerman Telegram

The U.S. entered WWII with the decryption of a message solved by the British Intelligence Agency. The Zimmerman Telegram was sent from the German Foreign Office in the U.S. to the German Ambassador to Mexico and proposed a military alliance between Germany and Mexico.


IBM developed a system called Lucifer in the 1960s, which was ultimately adopted by the U.S. National Bureau of Standards and is also known as the Data Encryption Standard (DES).


The RSA encryption system created in the 1970s was one of the first uses of asymmetric encryption.


One tactic used in encryption is called salting. This is where a random string of alphanumeric characters gets added to the end of the password before it’s encrypted. Salting adds extra security because even after the password gets decrypted, the “salt” has to be subtracted before it can be used. Even very obvious and common passwords can be difficult to figure out when they are salted.

Advanced Encryption Standard (AES)

Today’s default encryption mechanism used by the U.S. government is the Advanced Encryption Standard, or AES. It uses a 256-bit key and multiple rounds of encryption, known as substitution-permutation networking. AES has mostly replaced the formerly used Data Encryption Standard, or DES, which is now considered to be less secure.

Other Forms of Encryption

There are countless other forms of encryption. Some of the commonly used ones are:

•  Triple DES
•  Blowfish
•  Twofish
•  ElGamal
•  Hash Functions
•  Diffie-Hellman Key Exchange

Cryptocurrency and Cryptography

Cryptography is an integral part of blockchain technology and cryptocurrencies. Transactions and balances are tracked on a ledger and encrypted using complicated algorithms. This helps with security, transparency, and tracking. Crypto wallets also rely on cryptography for security.

Each type of digital asset or cryptocurrency has its own form of cryptography, making some more secure or popular than others and providing different use cases. Before investing in cryptocurrencies, it’s important to have at least a basic understanding of the way the technology works, especially the use of public and private keys. This will help decide which cryptocurrency to invest in and ensure that the transaction and digital asset storage is done securely.

The Future of Cryptography

As time goes on, it gets more and more challenging to maintain secure encryption of information. Computers and hackers get more sophisticated, and even the most impenetrable codes can be cracked using psychological tactics and social engineering.

Two tools that help increase security are two-factor authentication (2FA) and Honeypots. Each of them works slightly differently, though with the same goal.

•  With 2FA, the user must input a code retrieved from a text message or app on their phone in addition to their password. This means that an account can’t be accessed without access to the individual’s phone.
•  Honeypots trick attackers by creating false data that looks real and then alerting organizations when the attackers attempt to do a hack.

A newer form of cryptography is called homomorphic encryption. This attempts to solve one of today’s major cryptographic problems: the fact that data cannot be processed while it’s encrypted. This means that data has to be encrypted before it can be used for anything, making it vulnerable during that processing time. Homomorphic encryption allows users to process data while it’s encrypted, and then simply decrypt the final result.

The next wave of encryption will likely involve the use of quantum computers and post-quantum cryptography. These add layers of encryption beyond today’s capabilities. However, this technology is still in development.

The Takeaway

The history of cryptography is long and fascinating, and the technology has gotten more essential and complex over time. In today’s world, cryptography underpins everything from social media to financial transactions. That’s why it’s so important to make sure you keep your data and information safe using strong passwords, two-factor authentication, and other tools.

If you’re starting to invest in cryptocurrencies, you’ll need a basic understanding of public and private keys. One way to get started investing in cryptocurrencies is with SoFi Invest®. The investing platform allows you to research, trade digital assets right from your phone, and view all of your financial information in one simple dashboard.

Find out how to invest in crypto with SoFi Invest.

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