Cryptography is nothing but the science behind securing communications and data by encoding it in such a way that only authorised parties would be able to access or read it. In layman’s terms, it is the art of encoding and decoding secrets. You may read in mystery books how spies and detectives would hide a cipher or use invisible ink to convey messages. Today, data encryption is far more advanced, which uses technologies to protect sensitive or confidential information from unauthorised parties. In recent years, encryption has been used to secure everything from your bank account to classified government data.
The term “Cryptography” derives from a Greek word meaning “Hidden Writing”. The communication using secret code dates back to ancient times, as rulers, generals, and scribes used secret scripts to protect messages from prying eyes. While there is no solid evidence of exactly when cryptography was invented, it dates back well before the Internet came into the picture. Let’s deep dive into the history of cryptography.
Ancient Cryptography: Greeks’ Scytale And Romans’ Caesar Cipher
One of the earliest known methods of cryptography originated in ancient Sparta, Greece. They used a tool called a scytale, or skytale, a wooden rod around which a strip of leather was wrapped. When the leather was unwrapped, the letters appeared scrambled. Only someone with a rod of the same size could decipher the message properly.
Another popular cryptographic method from back then was the Caesar Cipher, named after the renowned Roman general and statesman, Julius Caesar. His idea of encryption was simple: He replaced each letter of a word with one a few positions away in the alphabet. For example: shifting A to D, B to E, or C to F. Also known as the Shift Cipher, it was used to send military messages.
The Middle Ages: Arabian Scholars’ Frequency Analysis
As time passed, people developed more complex methods for securing messages. At the same time, others tried to break these codes. One of the important developments in this field was made by the Arab scholars. Abu Yusuf Yaʻqub ibn ‘Ishaq as-Sabbah al-Kindi, also known as Al-Kindi, a scholar and scientist, discovered a method called Frequency Analysis, which looked at how often a letter appeared in a message. It was considered the very first structured code-breaking method.
In the 16th century, an evolved polyalphabetic cipher, the Vigenere cipher was invented. Although it has been attributed to Blaise de Vigenere, it was actually invented by Giovan Battista Bellaso in 1553. Instead of using a single shift like the Caesar Cipher, it used a keyword to change the shift throughout the message. This made it much more difficult to crack. The cipher remained unbroken for three centuries until the German infantry officer, cryptographer, and archaeologist Friedrich Kasiski cracked it in 1863 using pattern recognition and analysis.
Cryptography During World War II
In the 20th century, machines came into the picture. During this time, encryption moved from simple mechanical devices to the early ideas that shaped modern digital security. In the early 1900s, an American inventor named Edward Hebern created the first rotor-based encryption machine. It used electrical circuits along with parts of a typewriter. When a user typed a message, the machine automatically turned it into a coded form. To decipher the message, users had to reverse the rotor settings and type the coded message into the machine.
After World War I, German cryptologist Arthur Scherbius improved Hebern’s idea and developed the famous Enigma machine. During World War II, Germany used this machine to send highly classified information. These messages could only be read if someone had the exact settings and keys used for encryption. Following years of efforts, a team of codebreakers, led by British mathematician Alan Turing, were able to decode these messages.
Later in the century, especially in the 1970s, a new and powerful encryption was developed. This was called asymmetric encryption, or public-key cryptography. Unlike previous methods, it did not require both sides to share a secret key in advance. Instead, it used two keys. First, a public key to encrypt the message and a private key to decode it. Today, this method is used everywhere, from secure websites to email encryption.
Cryptography Used In Blockchain
In recent years, cryptography has become the foundation of blockchain technology and cryptocurrencies such as Bitcoin. Blockchain is a digital system that records transactions in a secure and transparent way. It does not rely on a central authority, such as a bank, and uses cryptography to establish trust. It began with the introduction of Bitcoin in 2008, created by an anonymous person or a group known as Satoshi Nakamoto. It showed how cryptography could be used not just for secret messages but for creating an entirely new kind of financial system.
Challenges In Modern Cryptography
Today’s encryption systems are strong enough to resist brute-force attacks from normal computers. However, the rise of quantum computing could change this completely. A powerful quantum computer can solve the mathematical problems underlying popular encryption methods. If that happens, it could put many important systems, including websites and digital identities, at risk.
Due to this, experts are now focusing on something called post-quantum cryptography, which would use the laws of quantum physics to securely share keys.