Cryptography 101: Why is it essential for Digital Security?

Simply put, without cryptography, nearly everything in the digital space would be predictable — and therefore insecure.

But how?

Imagine having a random number generator that creates a sequence of numbers. The shorter the sequence, the easier it would be to guess. Think of a 4-digit PIN; it’s relatively easy to break because it only has 10,000 possible combinations. But add just one or two digits, and suddenly there are hundreds of thousands or even millions of possibilities. By adding more digits, the potential combinations increase, making it increasingly challenging to predict correctly.

Cryptography builds on this concept of unpredictability but extends it with more sophisticated but reliable methods. Instead of simply adding more digits to a PIN to make it harder to predict, cryptographic algorithms use complex mathematical functions and and keys to create ‘locks’ on information, trying to make it computationally infeasible (without quantum computing) to guess or crack the encrypted information without the correct key — provided that the cryptographic primitive is robust [1], the key size is sufficient [2] , and the mode of operation is sound [3].

Okay, let’s suppose this: you want to send a message across a crowded room. If you shout it, anyone can hear. But if you use a secret code only you and your friend can understand, the message remains private even if others hear it — they can only predict what you sent. In the digital world, encryption works similarly. Messages are transmitted openly across networks, but encryption transforms them so that only someone with the correct key can decode and make sense of them.

Just to make sure we understand how cryptography allows us to achieve confidentiality like in the example above, let’s break down a few basic terms that tend to appear often:

• Encryption: This is a process of turning an input (like a plain text or message) into a some arbitrary code that appears meaningless to unauthorized users and is designed to be unreadable without a specific decryption key. In the image below, this encoded string is shown as ‘6EB6957008E03CE4’ in the blue box, which Alice then decrypts to reveal the original message.
• Key: Think of this as a special password or unique code that locks and unlocks the message. Only someone with…