Cryptography has evolved over thousands of years, shaping how we protect secrets and build trust. Let’s explore its key milestones with examples to help you understand and remember the central ideas.
What Happened?
Scribes in Ancient Egypt used altered hieroglyphs to encode messages. For example, instead of a bird symbolizing “freedom,” they might use a fish to represent something entirely different.
Why Was It Important?
This early form of encryption protected sacred texts, royal orders, and trade secrets. Only priests or trusted individuals who knew the code could decipher the meaning.
Example:
A pharaoh sends a message to his general: “Attack at dawn.” Instead of writing it plainly, the scribe uses symbols like a lion (strength) and a rising sun (east). To outsiders, it looks like random pictures, but the general understands the hidden plan.
What Happened?
Julius Caesar shifted letters in the alphabet by a fixed number (e.g., A → D, B → E) to send secret military messages.
Why Was It Important?
This was one of the first systematic encryption methods, showing how patterns could secure communication.
Example:
Caesar sends a message: “Meet me at the river.” Using a shift of 3, it becomes “Phhw ph dw wkh ulvhu.” Only someone who knows the shift can decode it.
What Happened?
The Germans used the Enigma Machine to scramble messages with millions of possible combinations. Each letter was encrypted differently based on rotor settings.
Why Was It Important?
The Enigma Machine demonstrated the power of technology in cryptography. Its breaking by Alan Turing and his team using the Bombe machine turned the tide of the war.
Example:
A German officer types “Attack at midnight” into the Enigma Machine. The output is a scrambled code like “XLMW MW EPI RMKZGVI.” Without the correct rotor settings, the message is unreadable.
What Happened?
Computers enabled public-key cryptography, where two keys (public and private) are used to encrypt and decrypt messages. RSA encryption used prime numbers to create unbreakable codes.
Why Was It Important?
Digital encryption became essential for protecting data in the internet age, enabling secure online transactions, emails, and banking.
Example:
You buy shoes online and enter your credit card number. The website encrypts your data using a public key. Only the store’s private key can decrypt it, ensuring hackers can’t steal your information.
What Happened?
In 2008, Satoshi Nakamoto introduced Bitcoin, powered by blockchain—a decentralized ledger secured by cryptography. Transactions were verified by miners and recorded immutably.
Why Was It Important?
Blockchain removed the need for middlemen, enabling trustless systems for money transfer, voting, supply chains, and more.
Example:
You send Bitcoin to a friend. Your transaction is verified by miners, added to a block, and linked to the blockchain. Once recorded, it cannot be changed, ensuring transparency and security.
