You’re about to wind up your day and use your smartphone to check what’s in your smart fridge to decide if you need to pass by the store or request delivery before you get home. You quickly pay for the purchase using your credit card registered on your account and promptly receive a push notification confirming the purchase and estimated delivery times.

You use your Metro transit card to jump on the bus or subway train to start making your way home, all the while listening to your favorite podcast on Spotify. Once you get home, you pick up your dinner and jump on to a Zoom call with your loved ones, quickly glancing to confirm the green padlock is active and your call is secure.

Your typical day may resemble the above or some aspects of it, but everything that we take for granted in a typical day requires some form of cryptography. A tiny bit of code that keeps us safe in the digital world — who to trust, who we say we are, was our data tampered with before delivery, or even if we are allowed to access a website.

Yet the word cryptography evokes images of spies (James Bond included), secret messages, covert government agencies, conspiracy theories, and wars flood our minds at the mention of ‘cryptography.’ In fact, movies like “The Da Vinci Code” and “The Imitation Game” revolve around this fascinating science of concealing information.


What is Cryptography?

Simply put, cryptography is the method of scrambling data so that it looks like gibberish to anyone except those who know the trick to decode it. Regardless of whether the data is being transmitted or at ‘rest’ in storage, cryptography uses algorithms to encrypt data, so that only the intended recipient can process the data.

As we delve deeper into cryptography, the following keywords will keep cropping up, and better to mention them now before proceeding further.

  • Encrypt – scrambling data to make it incomprehensible.
  • Decrypt – unscrambling encrypted data to its original comprehensible format.
  • Plaintext – unencrypted or decrypted data; could be text, images, audio, or video.
  • Ciphertext – encrypted data.
  • Cipher – another word for an encryption algorithm used to scramble data.
  • Key – a complex sequence of characters generated by the encryption algorithm, allowing scrambling and unscrambling data.

A textbook cryptography scenario would thus play out as:

Alice wants to communicate with Bob but does not want Eve to read or overhear their conversation. Alice encrypts her message (plaintext) using a cryptographic algorithm with a secret ‘key’ (only known to Alice and Bob) to create and send the encrypted message — ciphertext. Eve may intercept but will not be able to understand the ciphertext. Bob receives the encrypted message and immediately applies the secret key while reversing the cryptographic algorithm – decrypting the message back into plaintext.

Image: DZone

If you are familiar with cryptography, then you have probably come across Alice and Bob. If you have ever wondered how this cryptographic couple came to be, this article provides a quaint timeline.

While we may be content to leave cryptography to the experts and movies, it is all around us. From the moment you unlock your phone in the morning, access a website, make an online payment, watch Netflix, or purchase an NFT.

It’s hard to believe, but cryptography has been around for thousands of years. Early cryptography focused on protecting messages during transportation between allies. Modern cryptography matured to verify data integrity, authenticate identities, implement digital signatures, and many others.

The etymology of cryptography traces its roots back to the Greek words ‘Kryptos’ meaning ‘hidden’ and ‘graphein,’ meaning ‘writing.’ Ironically, American artist Jim Sanborn erected a sculpture aptly named ‘Kryptos,’ on the Central Intelligence Agency (CIA) grounds in Langley, Virginia. Yet to be fully deciphered, the sculpture displays scrambled letters hiding a secret message in plain sight in harmony with its location, name, and theme.

If cryptography is so old, why don’t we know more about it?

“History is written by the victors.” It is unlikely that a victorious army or government will publish details of secret weapons used to win wars. Herein lies the reason why little history on this important topic and its evolution exists. But, what do we know for sure?


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