Cryptography

Key people

• Alan TuringEnglish computer scientist (1912–1954)
• Claude ShannonAmerican mathematician and information theorist (1916–2001)
• François VièteFrench mathematician (*1540 – †1603)
• Marian RejewskiPolish mathematician and cryptologist (1905–1980)

Timeline

• 1900 BCE1900 BCE), but this may have been done for the amusement of literate observers rather than as a way of concealing information.
• 1970In symmetric systems, the only ones known until the 1970s, the same secret key encrypts and decrypts a message.
• 1990Export controls In the 1990s, there were several challenges to US export regulation of cryptography.
• 1993Another instance of the NSA's involvement was the 1993 Clipper chip affair, an encryption microchip intended to be part of the Capstone cryptography-control initiative.
• 1995The 1995 case Bernstein v.

Read

• The Code BookSimon Singh · 1999Book
• Introduction to modern cryptographyJonathan Katz · 2007Book
• Applied CryptographyBruce Schneier · 1994Book
• Cryptography and Network SecurityWilliam Stallings · 2002Book

Watch

• 7 Cryptography Concepts EVERY Developer Should KnowFireshipVideo
• What is Cryptography? | Introduction to Cryptography | Cryptography for Beginners | Edurekaedureka!Video
• Cryptography and Digital SignatureTeluskoVideo

Listen

• Cryptography FMSymbolic SoftwarePodcast
• IWCC-CIS-601 - Introduction to CryptographyJustin E. MillerPodcast
• The Bad Crypto PodcastJoel Comm and Travis WrightPodcast
• CRYPTO 101Bryce Paul & Brendan ViehmanPodcast

Voices to follow

• Chris Peikert@ChrisPeikert · XSRI International; School of Computer Science, Georgia Institute of Technology
• Jaap Henk Hoepman@xotoxot · XDutch computer scientist
• Jean Loup Le Roux@_jllr_ · XCanadian and French consultant and entrepreneur
• Aline Gouget@aline_gouget · XFrench mathematician

Debates

• Is perfect secrecy achievable and practical for modern communication?One view: Yes, with methods like one-time pads, perfect secrecy is mathematically proven and can be used for highly sensitive data. · Another: No, one-time pads are impractical for large-scale, dynamic communication due to key distribution challenges.Open question
• Should governments mandate 'backdoors' in encrypted systems for law enforcement access?One view: Yes, backdoors are necessary for national security and investigating serious crimes, with proper legal oversight. · Another: No, backdoors inherently weaken security for everyone, making systems vulnerable to malicious actors and authoritarian regimes.Open question
• Are current post-quantum cryptographic algorithms truly ready for widespread deployment?One view: Yes, significant research has validated several candidates, and early adoption is crucial to prepare for future quantum threats. · Another: No, the field is still evolving, and rushing deployment could introduce new vulnerabilities or lead to costly replacements later.Open question

Glossary

• EncryptionThe process of converting information into a code to prevent unauthorized access.
• DecryptionThe process of converting encrypted information back into its original, readable form.
• AlgorithmA step-by-step procedure or formula used to perform a specific task, like encryption or decryption.
• KeyA piece of information, often a string of characters, used with an algorithm to encrypt or decrypt data.
• CiphertextThe encrypted form of a message, unreadable without the correct key.
• PlaintextThe original, unencrypted message or data.

Careers

Roles this can lead toward

Threads 13

Where this connects to other fields — and why it's worth knowing.

• The Art Market Arts

  A digital picture can be copied a million times perfectly, so how do you make one 'the real one'? NFTs used clever math to stamp a single copy as the official original. Long ago the critic Walter Benjamin argued that copying kills the special 'aura' a real artwork has, and NFTs were basically an attempt to fake that aura back with code.

• Political Philosophy Philosophy

  Philosophers spent centuries on one puzzle: how do strangers with no king or referee agree on what's true and fair? Blockchains, like the tech behind Bitcoin, smacked straight into that same puzzle, thousands of strangers online with no boss. Their answer was 'consensus algorithms,' math recipes that let a crowd agree on the truth without trusting anyone in charge.

• Latitude, Longitude, and GPS Geography

  Your phone finds itself by listening to signals from GPS satellites, but those signals carry no signature and no proof they're real. Your phone just trusts them. That means anyone with a cheap gadget can broadcast fake signals and make your phone think it's somewhere else, which is a scary hole in everything from ships to war drones.

• Semiotics Media

  A red rose means 'love' only because we both learned that code; to someone who didn't, it's just a plant. A secret message you can't read is either an enemy's cipher or pure gibberish, same thing from the outside. So understanding any symbol and cracking a secret code are the same act: you need the shared key that unlocks the meaning.

• Censorship & Banned Books Literature

  For centuries, banning a book was a chase between writers and censors. Now that chase is math. Encryption scrambles messages and mesh networks pass them phone-to-phone with no center, so there's simply no single switch a government can flip off. The freedom to write now leans on equations, not just courage.

• Media Law & Freedom of the Press Media

  Strong encryption can lock a message so tightly that no government on Earth can force it open. That means some speech becomes literally impossible to regulate. The 'crypto wars' are lawmakers slamming into hard math they can't vote away, so this kind of freedom rests on a proven theorem, not on anyone's permission.

• Internet Censorship Media

  End-to-end encryption scrambles a message so only you and your friend can read it, and no government can peek. That's the one kind of speech no censor can block. Which is why the real battle over free speech online is a decades-long math fight, not just a policy debate.

• Deepfakes Media

  When deepfakes make any video look fake-able, staring harder won't save us. We'll trust images the same way we trust money moving between banks: with a cryptographic signature, a secret math stamp that proves a photo is real, like verifying a bank transfer.

• Corruption and Governance Politics

  Bribery and secret codes are both really about trust. When you can't trust officials to be honest, people reach for cryptography, math so tight that cheating becomes impossible to hide. It swaps 'please be honest' for a guarantee no one can fake, backed by numbers instead of morals.

• Disinformation and Elections Politics

  A deepfake fools you because you can't check who really made a video. The fix reporters want, a hidden cryptographic stamp proving where a clip came from, is the same trust tech that keeps your bank app safe. Spotting fake videos and protecting your money turn out to be the same puzzle.

• Endangered and Dying Languages Literature

  In World War II, the US had Navajo soldiers send battle messages in their own language, and the enemy never cracked it. A language almost nobody outside the tribe spoke worked as an unbreakable code. Its strength was simply how few people on Earth could understand it.

• Cybercrime Law Law

  The same secret-code math that locks your bank login so no one can steal it also lets criminals lock up hospital files and demand ransom, and move money no police can trace. It's one tool with two faces, good and evil. And once the math is known, no law can un-invent it.

• Data Privacy Law Law

  A law can promise "we'll protect your privacy," but promises get broken. Differential privacy does something wilder: it mixes carefully measured random noise into the data, so you can actually prove with math that nobody can spot you. Privacy becomes arithmetic instead of a pinky-swear.