مواضيع في علم التعمية

التعمية (cryptography) هي ممارسة ودراسة إخفاء البيانات؛ تتقاطع في علم التعمية المعاصر كل من الهندسة والرياضيات وعلم الحاسوب. يحظى هذا العلم اليوم بمكانة مرموقة بين العلوم، إذ تنوعت تطبيقاته العملية لتشمل مجالات متعددة نذكر منها: المجالات الدبلوماسية والعسكرية، والأمنية، والتجارية، والاقتصادية، والإعلامية، والمصرفية والمعلوماتية، ومن تلك التطبيقات: التجارة الإلكترونية وكلمات سر الحاسوب، وبطاقات إي تي إم.

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

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Essence of cryptography

Main article: Cryptography

Uses of cryptographic techniques

Commitment schemes -
Secure multiparty computations -
Electronic voting -
Authentication -
Digital signatures -
Crypto systems -
Dining cryptographers protocol - by David Chaum
Anonymous remailer -
Pseudonymity -
Anonymous internet banking -
Onion routing -

Branches of cryptography

History of cryptography

Ciphers

Classical

Vigenère -

Polygraphic -

Playfair - by Charles Wheatstone
Hill -

Substitutions -

Caesar -

ROT13 -

Affine -
Atbash -

Transposition -

Scytale -
Grille -
VIC - 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 ciphers

A5/1 & A5/2 - cyphers 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 mid-'20s; 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
SEAL -
SNOW -
SOBER -

SOBER-t16 -
SOBER-t32 -

WAKE

Block ciphers

Product cipher -
Feistel cipher - pattern by Horst Feistel
Advanced Encryption Standard (Rijndael) - 128 bit block; NIST selection for the AES, FIPS 197, 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
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 bits)
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 30s and into WWII

Asymmetric key algorithms

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 -
Merkle-Hellman knapsack cryptosystem - knapsack scheme
McEliece -
Niederreiter cryptosystem -
NTRUEncrypt -
RSA - factoring

RSA-KEM - NESSIE selection asymmetric encryption scheme; ISO/IEC 18033-2 draft
RSA-OAEP - CRYPTREC recommendation

Rabin cryptosystem - factoring

Rabin-SAEP -
HIME(R) -

Threshold cryptosystem -
XTR -

Keys

Authentication

Public key infrastructure -

X.509 -

Public key certificate -

Transport/exchange

Weak keys

Cryptographic hash functions

EMAC - NESSIE selection MAC
HMAC - NESSIE selection MAC; ISO/IEC 9797-1, FIPS 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

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

RIPEMD-160 - developed in Europe for the RIPE project, 160-bit digest;CRYPTREC recommendation (limited)
Tiger - by Ross Anderson et al.
Snefru -
Whirlpool - NESSIE selection hash function, Scopus Tecnologia S.A. (Brazil) & K.U.Leuven (Belgium)

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Cryptanalysis

Classical

Modern

Symmetric algorithms

Hash functions:

Birthday attack

Attack models

Side channel attacks

Power analysis -
Timing attack -

Network attacks

External attacks

Black-bag -
Rubber-hose -

Robustness properties

Uncracked codes and ciphers

Organizations and selection projects

Standards

Federal Information Processing Standards 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
ANSI - standardization process that produces many standards in many areas; some are cryptography related, ongoing)
ISO - standardization process produces many standards in many areas; some are cryptography related, ongoing
IEEE - standardization process produces many standards in many areas; some are cryptography related, ongoing
IETF - standardization process that produces many standards called RFCs) in many areas; some are cryptography related, ongoing)

General cryptographic

NSA - internal evaluation/selections, charged with assisting NIST in its cryptographic responsibilities
GCHQ - internal evaluation/selections, a division is charged with developing and recommending cryptographic standards for the UK government
DSD - Australian SIGINT agency, part of ECHELON
Communications Security Establishment (CSE) - Canadian intelligence agency

Open efforts

DES - NBS selection process, ended 1976
RIPE - division of the RACE project sponsored by the European Union, ended mid-'80s
AES - a "break-off" competitiosponsored 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
Internet Engineering Task Force - technical body responsible for Internet standards— the Request for Comment series is ongoing
CrypTool - an e-learning freeware programme in English and German— exhaustive educational tool about cryptography and cryptanalysis