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Mathematics

The Mathematics of Public Key Cryptography and Digital Signatures

Quick fact

Bitcoin and many secure websites rely on a single mathematical concept: a function that is easy to compute in one direction but nearly impossible to reverse without a secret 'trapdoor.' For example, multiplying two large prime numbers is quick, but factoring their product is extremely hard—a 232-digit number has never been publicly factored.

Why this is interesting

You've used it every time you bought something online, but have you ever wondered how a website can prove its identity to your browser without sharing a secret password? The answer is pure math—the same math that lets you lock a box with a padlock anyone can close, but only you can open.