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Cryptography — Learning Library

Why designs are public

masiarek/cryptography-learning-library

Cryptography — Learning Library

masiarek/cryptography-learning-library

Home
Start Here
Start Here
What Cryptography Is
What Cryptography Is
- What a key is
  What a key is
- Kerckhoffs's principle
  Kerckhoffs's principle
Classical Ciphers
Classical Ciphers
- Breaking a cipher by counting
  Breaking a cipher by counting
- The one-time pad
  The one-time pad
Randomness
Randomness
- random is not secrets
  random is not secrets
Hashing
Hashing
- A hash is not encryption
  A hash is not encryption
Symmetric
Symmetric
- AES has no modes — you pick one
  AES has no modes — you pick one
- ECB leaks the picture
  ECB leaks the picture
Integrity and MACs
Integrity and MACs
- HMAC, and comparing in constant time
  HMAC, and comparing in constant time
Public Key
Public Key
- Diffie–Hellman by hand
  Diffie–Hellman by hand
- RSA by hand, and why textbook RSA is broken
  RSA by hand, and why textbook RSA is broken
Passwords
Passwords
- Hashing a password
  Hashing a password
Protocols
Protocols
- JWT, and the alg:none hole
  JWT, and the alg:none hole
- What a TLS handshake actually does
  What a TLS handshake actually does
How It Breaks
How It Breaks
- Nonce reuse
  Nonce reuse
- Timing attacks
  Timing attacks
Real World
Real World
- Key management
  Key management
- Cryptography in SAP
  Cryptography in SAP
History
History
- Why designs are public
  Why designs are public
Frontier
Frontier
- Post-quantum, and what "harvest now" means
  Post-quantum, and what "harvest now" means
Glossary
Resources
Roadmap

Why designs are public¶

Level: reference · for context

Stub — an outline, not a lesson. There is no runnable example behind this page yet, so nothing on it has been through the check that backs every other claim in this library. The bullets below are the questions the finished page has to answer.

One line: The field's habits are scar tissue, and each rule has a specific failure behind it.

The questions this page has to answer¶

Enigma: broken by procedure and crib, not by mathematics — and what that says about operator error.
DES: a 56-bit key that was short on purpose, and the twenty-year argument about why.
The Crypto Wars, export grades, and the 'export-grade' ciphersuites that were still exploitable in 2015 (FREAK, Logjam).
Dual_EC_DRBG: a standard with a back door, and how it was found.
AES and SHA-3: why an open competition became the only acceptable way to pick a standard.

See also¶

12_History — the chapter this belongs to
ROADMAP.md — where this sits in the queue