#rsa

2 articles

01 ·Security·FREE·PAPER·20 min read RSA from Scratch — The Number Theory Behind Public Keys RSA lets you publish a key that locks but cannot unlock. This builds it from congruence arithmetic up: key generation, the two modular exponentiations, and a line-by-line proof from Euler's theorem of why the message comes back — then a worked example small enough to check by hand, why factoring is the security assumption, and why textbook RSA must never be shipped without padding. 02 ·Security·FREE·13 min read Cryptography from Scratch — Symmetric Keys, Public Keys, and Hashes Cryptography isn't about producing unreadable text — it's about engineering an extreme gap in effort between people who hold the key and people who don't. We build up the three tools (symmetric, public-key, hashing) from zero, explain why factoring shows up at all, what a signature actually promises, and how every widely deployed cipher has eventually broken.