The following outline is provided as an overview of and topical guide to cryptography:

Cryptography (or cryptology) practice and study of hiding information. Modern cryptography intersects the disciplines of mathematics, computer science, and engineering. Applications of cryptography include ATM cards, computer passwords, and electronic commerce.

Essence of cryptography

• Cryptographer

• Encryption/decryption

• Cryptographic key

• Cipher

• Ciphertext

• Plaintext

• Code

• Tabula recta

• Alice and Bob

Uses of cryptographic techniques

• Commitment schemes

• Secure multiparty computation

• Electronic voting

• Authentication

• Digital signatures

• Crypto systems

• Dining cryptographers problem

• Anonymous remailer

• Pseudonymity

• Onion routing

• Digital currency

• Secret sharing

• Indistinguishability obfuscation

Branches of cryptography

• Batch cryptography

• Chaotic cryptology

• Multivariate cryptography

• Post-quantum cryptography

• Quantum cryptography

• Steganography

• Visual cryptography

History of cryptography

• Japanese cryptology from the 1500s to Meiji

• World War I cryptography

World War II cryptography

• Reservehandverfahren

• Venona project

• Ultra

Ciphers

Classical

Substitution cipherSubstitution

Monoalphabetic substitution

Caesar cipher

• ROT13

• Affine cipher

• Atbash cipher

• Keyword cipher

Polyalphabetic substitution

• Vigenère cipher

• Autokey cipher

• Homophonic substitution cipher

Polygraphic substitution

• Playfair cipher

• Hill cipher

Transposition cipherTransposition

• Scytale

• Grille

• Permutation cipher

• VIC cipher complex hand cypher used by at least one Soviet spy in the early 1950s; it proved quite secure for the time

Modern symmetric-key algorithms

Stream ciphersStream ciphers

• A5/1 & A5/2 ciphers specified for the GSM cellular telephone standard

• BMGL

• Chameleon

• FISH by Siemens AG

WWII 'Fish' cyphers

• Geheimfernschreiber WWII mechanical onetime pad by Siemens AG, called STURGEON by Bletchley Park

• Pike improvement on FISH by Ross Anderson

• Schlusselzusatz WWII mechanical onetime pad by Lorenz, called tunny by Bletchley Park

• HELIX

• ISAAC intended as a PRNG

• Leviathan

• LILI-128

• MUGI CRYPTREC recommendation

• MULTI-S01 - CRYPTREC recommendation

• One-time pad Vernam and Mauborgne, patented 1919; an extreme stream cypher

• Panama

RC4 (ARCFOUR) one of a series by Professor Ron Rivest of MIT; CRYPTREC recommended limited to 128-bit key

• CipherSaber (RC4 variant with 10 byte random IV, easy to implement

Salsa20 an eSTREAM recommended cipher

• ChaCha20 A Salsa20 variant.

• SEAL

• SNOW

SOBER

• SOBER-t16

• SOBER-t32

• WAKE

Block ciphersBlock ciphers

• Product cipher

• Feistel cipher pattern by Horst Feistel

• Advanced Encryption Standard (Rijndael) 128-bit block; NIST selection for the AES, FIPS 197; Created 2001—by Joan Daemen and Vincent Rijmen; NESSIE selection; CRYPTREC recommendation.

• Anubis 128-bit block

• BEAR built from a stream cypher and hash function, by Ross Anderson

• Blowfish 64-bit block; by Bruce Schneier et al.

• Camellia 128-bit block; NESSIE selection (NTT & Mitsubishi Electric); CRYPTREC recommendation

CAST-128 (CAST5) 64-bit block; one of a series of algorithms by Carlisle Adams and Stafford Tavares, insistent that the name is not due to their initials

• CAST-256 (CAST6) 128-bit block; the successor to CAST-128 and a candidate for the AES competition

• CIPHERUNICORN-A 128-bit block; CRYPTREC recommendation

• CIPHERUNICORN-E 64-bit block; CRYPTREC recommendation (limited)

• CMEA cipher used in US cellphones, found to have weaknesses.

• CS-Cipher 64-bit block

• Data Encryption Standard (DES) 64-bit block; FIPS 46-3, 1976

• DEAL an AES candidate derived from DES

• DES-X a variant of DES to increase the key size.

• FEAL

• GDES a DES variant designed to speed up encryption

• Grand Cru 128-bit block

• Hierocrypt-3 128-bit block; CRYPTREC recommendation

• Hierocrypt-L1 64-bit block; CRYPTREC recommendation (limited)

• IDEA NXT project name FOX, 64-bit and 128-bit block family; Mediacrypt (Switzerland); by Pascal Junod & Serge Vaudenay of Swiss Institute of Technology Lausanne

• International Data Encryption Algorithm (IDEA) 64-bit block;James Massey & X Lai of ETH Zurich

• Iraqi Block Cipher (IBC)

• KASUMI 64-bit block; based on MISTY1, adopted for next generation W-CDMA cellular phone security

• KHAZAD 64-bit block designed by Barretto and Rijmen

• Khufu and Khafre 64-bit block ciphers

• Kuznyechik Russian 128-bit block cipher, defined in GOST R 34.12-2015 and RFC 7801.

• LION block cypher built from stream cypher and hash function, by Ross Anderson

• LOKI89/91 64-bit block ciphers

• LOKI97 128-bit block cipher, AES candidate

• Lucifer by Tuchman et al. of IBM, early 1970s; modified by NSA/NBS and released as DES

• MAGENTA AES candidate

• Mars AES finalist, by Don Coppersmith et al.

• MISTY1 NESSIE selection 64-bit block; Mitsubishi Electric (Japan); CRYPTREC recommendation (limited)

• MISTY2 128-bit block: Mitsubishi Electric (Japan)

• Nimbus 64-bit block

• NOEKEON 128-bit block

• NUSH variable block length (64-256-bit)

• Q 128-bit block

RC2 64-bit block, variable key length

• RC6 variable block length; AES finalist, by Ron Rivest et al.

• RC5 Ron Rivest

• SAFER variable block length

• SC2000 128-bit block; CRYPTREC recommendation

• Serpent 128-bit block; AES finalist by Ross Anderson, Eli Biham, Lars Knudsen

• SHACAL-1 160-bit block

• SHACAL-2 256-bit block cypher; NESSIE selection Gemplus (France)

Shark grandfather of Rijndael/AES, by Daemen and Rijmen

• Square father of Rijndael/AES, by Daemen and Rijmen

• TEA by David Wheeler & Roger Needham

• Triple DES by Walter Tuchman, leader of the Lucifer design team—not all triple uses of DES increase security, Tuchman's does; CRYPTREC recommendation (limited), only when used as in FIPS Pub 46-3

• Twofish 128-bit block; AES finalist by Bruce Schneier et al.

• XTEA by David Wheeler & Roger Needham

• 3-Way 96-bit block by Joan Daemen

Polyalphabetic substitution machine cyphers

• Enigma WWII German rotor cypher machine—many variants, any user networks for most of the variants

• Purple highest security WWII Japanese Foreign Office cypher machine; by Japanese Navy Captain

• SIGABA WWII US cypher machine by William Friedman, Frank Rowlett et al.

• TypeX WWII UK cypher machine

Hybrid code/cypher combinations

• JN-25 WWII Japanese Navy superencyphered code; many variants

• Naval Cypher 3 superencrypted code used by the Royal Navy in the 1930s and into WWII

Modern asymmetric-key algorithms

Asymmetric key algorithmAsymmetric key algorithm

ACE-KEM NESSIE selection asymmetric encryption scheme; IBM Zurich Research

• ACE Encrypt

• Chor-Rivest

• Diffie-Hellman key agreement; CRYPTREC recommendation

• El Gamal discrete logarithm

• Elliptic curve cryptography (discrete logarithm variant)

PSEC-KEM NESSIE selection asymmetric encryption scheme; NTT (Japan); CRYPTREC recommendation only in DEM construction w/SEC1 parameters

• ECIES Elliptic Curve Integrated Encryption System, Certicom Corporation

• ECIES-KEM

• ECDH Elliptic Curve Diffie-Hellman key agreement, CRYPTREC recommendation

• EPOC

• Kyber

• Merkle–Hellman knapsack cryptosystem knapsack scheme

• McEliece cryptosystem

• Niederreiter cryptosystem

• NTRUEncrypt

RSA factoring

• RSA-KEM NESSIE selection asymmetric encryption scheme; ISO/IEC 18033-2 draft

• RSA-OAEP CRYPTREC recommendation

Rabin signature factoring

• Rabin-SAEP

• HIME(R)

• Paillier cryptosystem

• Threshold cryptosystem

• XTR

Keys

Key authenticationKey authentication

Public key infrastructure

• X.509

• OpenPGP

Public key certificate

• Certificate authority

• Certificate revocation

• ID-based cryptography

• Certificate-based encryption

• Secure key issuing cryptography

• Certificateless cryptography

• Merkle tree

Transport/exchange

• Diffie–Hellman

• Man-in-the-middle attack

• Needham–Schroeder

• Offline private key

• Otway–Rees

• Trusted paper key

• Wide Mouth Frog

Weak keyWeak keys

• Brute force attack

• Dictionary attack

• Related key attack

• Key derivation function

• Key strengthening

• Password

• Password-authenticated key agreement

• Passphrase

• Salt

• Factorization

Cryptographic hash functionCryptographic hash functions

• Message authentication code

Keyed-hash message authentication code

• Encrypted CBC-MAC (EMAC) NESSIE selection MAC

• HMAC NESSIE selection MAC; ISO/IEC 9797-1, FIPS PUB 113 and IETF RFC

• TTMAC (Two-Track-MAC) NESSIE selection MAC; K.U.Leuven (Belgium) & debis AG (Germany)

• UMAC NESSIE selection MAC; Intel, UNevada Reno, IBM, Technion, & UC Davis

• Oblivious Pseudorandom Function

• MD5 one of a series of message digest algorithms by Prof Ron Rivest of MIT; 128-bit digest

SHA-1 developed at NSA 160-bit digest, an FIPS standard; the first released version was defective and replaced by this; NIST/NSA have released several variants with longer 'digest' lengths; CRYPTREC recommendation (limited)

• SHA-256 NESSIE selection hash function, FIPS 180-2, 256-bit digest; CRYPTREC recommendation

• SHA-384 NESSIE selection hash function, FIPS 180-2, 384-bit digest; CRYPTREC recommendation

• SHA-512 NESSIE selection hash function, FIPS 180-2, 512-bit digest; CRYPTREC recommendation

• SHA-3 originally known as Keccak; was the winner of the NIST hash function competition using sponge function.

• Streebog Russian algorithm created to replace an obsolete GOST hash function defined in obsolete standard GOST R 34.11-94.

• RIPEMD-160 developed in Europe for the RIPE project, 160-bit digest; CRYPTREC recommendation (limited)

• RTR0 one of Retter series; developed by Maciej A. Czyzewski; 160-bit digest

• Tiger by Ross Anderson et al.

• Snefru NIST hash function competition

• Whirlpool NESSIE selection hash function, Scopus Tecnologia S.A. (Brazil) & K.U.Leuven (Belgium)

CryptanalysisCryptanalysis

Classical

• Frequency analysis

• Contact analysis

• Index of coincidence

• Kasiski examination

Modern

Symmetric algorithms

• Boomerang attack

• Brute force attack

• Davies' attack

• Differential cryptanalysis

• Impossible differential cryptanalysis

• Integral cryptanalysis

• Linear cryptanalysis

• Meet-in-the-middle attack

• Mod-n cryptanalysis

• Related-key attack

• Slide attack

• XSL attack

Hash functions:

• Birthday attack

Attack models

• Chosen-ciphertext

• Chosen-plaintext

• Ciphertext-only

• Known-plaintext

Side channel attacks

• Power analysis

• Timing attack

• Cold boot attack

• Differential fault analysis

Network attacks

• Man-in-the-middle attack

• Replay attack

External attacks

• Black-bag cryptanalysis

• Rubber-hose cryptanalysis

Robustness properties

• Provable security

• Random oracle model

• Ciphertext indistinguishability

• Semantic security

• Malleability

• Forward secrecy

• Forward anonymity

• Freshness

Undeciphered historical codes and ciphers

• Beale ciphers

• Chaocipher

• D'Agapeyeff cipher

• Dorabella cipher

• Rongorongo

• Shugborough inscription

• Voynich manuscript

Organizations and selection projects

Cryptography standards

• Federal Information Processing Standards (FIPS) Publication Program run by NIST to produce standards in many areas to guide operations of the US Federal government; many FIPS publications are ongoing and related to cryptography

• American National Standards Institute (ANSI) standardization process that produces many standards in many areas; some are cryptography related, ongoing)

• International Organization for Standardization (ISO) standardization process produces many standards in many areas; some are cryptography related, ongoing

• Institute of Electrical and Electronics Engineers (IEEE) standardization process produces many standards in many areas; some are cryptography related, ongoing

• Internet Engineering Task Force (IETF) standardization process that produces many standards called RFCs) in many areas; some are cryptography related, ongoing)

General cryptographic

• National Security Agency (NSA) internal evaluation/selections, charged with assisting NIST in its cryptographic responsibilities

• Government Communications Headquarters (GCHQ) internal evaluation/selections, a division is charged with developing and recommending cryptographic standards for the UK government

• Defence Signals Directorate (DSD) Australian SIGINT agency, part of ECHELON

• Communications Security Establishment (CSE) Canadian intelligence agency

Open efforts

• Data Encryption Standard (DES) NBS selection process, ended 1976

• RIPE division of the RACE project sponsored by the European Union, ended mid-1980s

• Advanced Encryption Standard (AES) a "break-off" competition sponsored by NIST, ended in 2001

• NESSIE Project an evaluation/selection program sponsored by the European Union, ended in 2002

• eSTREAM program funded by ECRYPT; motivated by the failure of all of the stream ciphers submitted to NESSIE, ended in 2008

• CRYPTREC evaluation/recommendation program sponsored by the Japanese government; draft recommendations published 2003

• CrypTool an e-learning freeware programme in English and German exhaustive educational tool about cryptography and cryptanalysis

Influential cryptographers

List of cryptographers

Legal issues

• AACS encryption key controversy

Free speech

• Bernstein v. United States - Daniel J. Bernstein's challenge to the restrictions on the export of cryptography from the United States.

• Junger v. Daley

• DeCSS

• Phil Zimmermann - Arms Export Control Act investigation regarding the PGP software.

• Export of cryptography

• Key escrow and Clipper Chip

• Digital Millennium Copyright Act

• Digital rights management (DRM)

Patents

• RSA now public domain

• David Chaum and digital cash

Cryptography and law enforcement

• Telephone wiretapping

• Espionage

Cryptography laws in different nations

• Official Secrets Act United Kingdom, India, Ireland, Malaysia, and formerly New Zealand

• Regulation of Investigatory Powers Act 2000 United Kingdom

Academic and professional publications

• Journal of Cryptology

• Encyclopedia of Cryptography and Security

• Cryptologia quarterly journal focusing on historical aspects

• Communication Theory of Secrecy Systems cryptography from the viewpoint of information theory

• International Association for Cryptologic Research (website)

Allied sciences

• Security engineering

See also

• List of cryptography software

• Outline of computer science

• Outline of computer security

References