Cryptography is a technical science that studies cryptographic encoding and decoding. Studying the objective law of password change and applying it to compiling passwords to keep communication secrets is called coding; The act of obtaining communication information by deciphering passwords is called deciphering and cryptography.

Cryptography is an important secret means for communication parties to convert special information according to agreed rules. According to these laws, changing plaintext into ciphertext is called encryption transformation; Turning ciphertext into plaintext is called decryption transformation. In the early days, passwords only changed the encryption and decryption of characters or numbers. With the development of communication technology, voice, image and data can be encrypted and decrypted.

Cryptography is gradually developed in the practice of the struggle between encoding and decoding, and with the application of advanced science and technology, it has become a comprehensive frontier technology science. It is closely related to linguistics, mathematics, electronics, acoustics, information theory and computer science. Its actual research results, especially the encryption and decoding methods used by governments all over the world, are highly confidential.

The law of secret conversion is called cryptosystem. The parameter indicating this conversion is called the key. They are an important part of cryptography. The basic types of cryptographic systems can be divided into four types: confusion-changing the position of plaintext letters or numbers into ciphertext according to prescribed figures and lines; Substitution-replacing plaintext letters or numbers with ciphertext by one or more substitution tables; Codebook-change plaintext into ciphertext by replacing some phrases and words with pre-programmed alphanumeric cipher sets; Scrambling-a series of finite elements are used as random numbers, which are combined with plaintext sequences according to the specified algorithm to form ciphertext. The above four cryptographic systems can be used separately or mixed to compile various practical passwords with high complexity.

Since 1970s, some scholars have proposed public key system, that is, using the mathematical principle of one-way function to realize the separation of encryption and decryption keys. The encryption key is public and the decryption key is confidential. This new cryptosystem has attracted extensive attention and discussion in the field of cryptography.

Based on the laws of characters and passwords, under certain conditions, by analyzing the intercepted ciphertext, plaintext can be obtained, and the password can be restored, that is, the password can be cracked. Deciphering passwords with different strengths requires different conditions, even very different.

China ancient secret communication means, there have been some close to the prototype of the password. Ceng Gongliang and Ding Du in the Song Dynasty recorded that in the early years of the Northern Song Dynasty, a five-character rhythmic poem used 40 Chinese characters to express 40 situations or demands, which had the characteristics of secret edition.

187 1 year, 6,899 Chinese characters were selected by Shanghai Dabei Waterline Telegraph Company and replaced by four-code numbers, becoming the first commercial plain code in China. At the same time, a method of transforming plain code into password and scrambling it is designed. On this basis, it gradually developed into various more complex passwords.

In Europe, in 405 BC, Spartan general Le Sandroos used the original disordered code; In the first century BC, the Roman emperor Caesar replaced the password with an ordered single table; Later, it gradually developed into various cryptographic systems such as codebook, multi-table substitution and scrambling.

At the beginning of the twentieth century, the first batch of practical mechanical and electronic cipher machines appeared, and at the same time, commercial cipher machine companies and markets appeared. After the 1960s, the electronic cipher machine developed rapidly and was widely used, which made the development of cipher enter a new stage.

Password cracking is gradually produced and developed with the use of passwords. 14 12, an encyclopedia compiled by Kalekashandi, Persia, contains methods to decipher simple codes instead of passwords. By the end of16th century, some European countries had full-time decipherers to decipher the intercepted secret information. Cryptographic decoding technology has made great progress. Cryptography and Decoding Technology written by Prussian Kasinski and Military Cryptography written by Frenchman Kerckhoff both discussed and discussed the theory and methods of cryptography. Shannon, an American from 65438 to 0949, published the article Communication Theory of Secret Systems, and analyzed some basic problems in cryptography by applying the principle of information theory.

/kloc-since the 0/9th century, the widespread use of telegrams, especially wireless telegrams, has provided extremely favorable conditions for cryptographic communication and third-party interception. Communication secrecy and detection and decoding have formed a hidden front with fierce struggle.

19 17, Britain deciphered the telegram of German Foreign Minister Qi Merman, which prompted the United States to declare war on Germany. 1942, the United States learned the Japanese army's operational intention and deployment of troops in midway from deciphering the Japanese navy's secret report, so as to break the main force of the Japanese navy with inferior forces and reverse the war situation in the Pacific region. In many famous historical events such as defending the British Isles, the success of password cracking has played an extremely important role. These examples also illustrate the important position and significance of password secrecy from the opposite side.

At present, the governments of major countries in the world attach great importance to cryptography. Some of them have established huge institutions, allocated huge funds, concentrated tens of thousands of experts and scientific and technological personnel, and invested a lot of high-speed computers and other advanced equipment in their work. At the same time, private enterprises and academic circles pay more and more attention to cryptography, and many mathematicians, computer scientists and experts in other related disciplines have also devoted themselves to the research of cryptography, which has accelerated the development of cryptography.

Now cryptography has become an independent discipline. Cryptography in the traditional sense is to study how to transform information into a hidden way to prevent others from obtaining it.

Cryptography is an interdisciplinary subject, which comes from many fields: it can be regarded as information theory, but it uses tools in many mathematical fields, such as number theory and finite mathematics.

Original information, that is, information that needs password protection, is called plaintext. Encryption is the process of transforming the original information into an unreadable form, which is a password. Decryption is the reverse process of encryption, and the original information is obtained from the encrypted information. Password is an algorithm used for encryption and decryption.

The earliest steganography only needed pen and paper, and now it is called classical cryptography. Its two categories are permutation encryption and rearranging the order of letters; Replace encryption and replace a group of letters with other letters or symbols. The information of classical encryption methods is easily cracked by statistics. The more information, the easier it is to crack. It is a good method to use analysis frequency. Classical cryptography has not disappeared, and it often appears in intelligence games. At the beginning of the 20th century, some mechanical devices were invented for encryption, including the rotary wheel machine, the most famous of which was Enigma, a cipher machine used in World War II. The passwords generated by these machines greatly increase the difficulty of password analysis. For example, all kinds of attacks on Enigma were successful only after considerable efforts.

Traditional cryptography

Automatic key cipher

permutation cipher

Two-letter group instead of password (Charles Wheatstone)

Multi-letter replacement password

hill password

Virginia password

Replace password

Jimmy king Zum

ROT 13

affine cipher

Atbash password

Transposition cipher

sickle

Grid cipher

VIC password (a complicated manual password, which was used by at least one Soviet spy in the early 1950s and was very safe at that time).

An attack on traditional cryptography

frequency analysis

Coincidence index

Modern algorithm, method evaluation and selection engineering

Standard organization

Federal Information Processing Standards Publishing Program (managed by NIST, which produces standards in many fields to guide the operation of the US federal government; Many FIPS bars are related to cryptography.

ANSI standardization process (many standards are produced in many fields; Some related to cryptography, in progress)

ISO standardization process (produces many standards in many fields; Some related to cryptography, in progress)

IEEE standardization process (produces many standards in many fields; Some related to cryptography, in progress)

IETF standardization process (producing many standards in many fields (called RFC); Some related to cryptography, in progress)

See encryption standard.

Encrypted organization

NSA internal evaluation/selection (of course, it is extensive, and there is no public information about the process or results of internal use; The National Security Agency is accused of assisting NIST to perform its encryption duties)

GCHQ internal evaluation/selection (of course, it is extensive, and there is no open process or result for GCHQ to use; A department of GCHQ is responsible for developing and recommending encryption standards for the British government)

DSD is part of ECHELON, a SIGINT organization in Australia.

Communications Security Agency (CSE)-Canadian Intelligence Agency.

An open effort.

DES selection (NBS selection process, ending at 1976)

The mature part of the race project (sponsored by the European Union and ended in the mid-1980s)

AES competition ("interruption" sponsored by NIST; End at 200 1)

NESSIE project (EU-sponsored evaluation/selection plan; End of 2002)

CRYPTREC program (evaluation/recommendation project sponsored by the Japanese government; Draft recommendations published in 2003)

Internet engineering task force (technical organization responsible for Internet standards-consultation series: in progress)

CrypTool project (e-learning program in English and German; Free software; Detailed educational tools on cryptography and cryptanalysis)

Encrypted hash function (message digest algorithm, MD algorithm)

Encrypted hash function

Message authentication code

Keyed hash message verification code

Nisi chooses MAC.

HMAC (selected by Nishi MACISO/FIPS IEC 9797- 1 and IETF RFC)

TTMAC is also called dual-track MAC(nessie selection MAC；; Leuven Belgium; Debis ag (Germany)

UMAC (Nixi select MAC Intel, Renault, IBM, Technion and. UCal Davis)

MD5 (one of a series of message digest algorithms, proposed by Professor Ron Rivest of MIT; 128 bit abstract)

Sha- 1 (160 bit abstract is developed by NSA and is one of FIPS standards; The first released version was found to be defective and was replaced by this version; NIST/ National Security Agency released several variants with longer "abstracts"; Recommended by CRYPTREC (limited))

SHA-256 (NESSIE series message digest algorithm, 180-2, one of FIPS standards, with a digest length of 256 bits).

SHA-384 (Nissl message digest algorithm, one of FIPS standards, 180-2, the digest length is 384 bits; CRYPTREC suggested)

SHA-5 12 (NESSIE message digest algorithm, one of FIPS standards, 180-2, the digest length is 5 12 bits; CRYPTREC suggested)

RIPEMD- 160 (developed for RIPE project in Europe, 160 abstract; Recommended by CRYPTREC (limited))

Tiger (rose anderson et al.)

Snefru

Whirlpool (Loch Ness monster chooses hash function, Scopus Tecnologia S.A (Brazil) & ampK.U Leuven (Belgium))

Public/private key encryption algorithm (also known as asymmetric key algorithm)

ACE-KEM (NESSIE chooses asymmetric encryption scheme; IBM Zurich research)

ACE encryption

Chor- Rivest

Diffie-Hellman (key agreement; Recommended by CRYPTREC)

Discrete logarithm

ECC (Elliptic Curve Encryption Algorithm) (Discrete Logarithmic Variant)

PSEC-KEM (Nishi chooses asymmetric encryption scheme; NTT (Japan); CRYPTREC suggests using SEC 1 parameter only in DEM construction).

Elliptic curve comprehensive encryption system; Certicom company)

ECIES-KEM

ECDH (elliptic curve Diffie-Hellman key protocol; Recommended by CRYPTREC)

EPOC

Merkle-Hellman (knapsack scheme)

Mcellis

influence

RSA (factorization)

RSA-KEM (Nishi chooses asymmetric encryption scheme; ISO/IEC 18033-2 draft)

RSA-OAEP (recommended by Cryptrec)

Rabin Cryptosystem (Factorization)

Rabin -SAEP

HIME

XTR

Public/private key signature algorithm

DSA(zh: digital signature; Zh-tw: digital signature algorithm) (from NSA, Zh: digital signature; Zh-tw: Part of Digital Signature Standard (DSS): recommended by CRYPTREC)

Elliptic curve DSA (NESSIE chooses digital signature scheme; Certicom company); CRYPTREC suggests ANSI X9.62, SEC 1).

Schnorr signature

RSA signature

RSA-PSS (NESSIE chooses digital signature scheme; RSA lab); CRYPTREC suggested)

Rsassa-pkcs1v1.5 (suggested by cryptrec)

Signed by Nieberg-Roupell

MQV protocol

Gennaro-Halevi-Rabin signature scheme

Cramer-Shoup signature scheme

One-time signature

Lamport signature scheme

Bos-Chaum signature scheme

An undeniable signature

Chaum-van Antwerpen signature scheme

Failed to stop signing

Ong-Schnorr-Shamir signature scheme

Bi-rational permutation scheme

design

Design -D

Design -R

Direct anonymous proof

NTRUSign is a public key encryption algorithm for mobile devices. The key is short, but it can also achieve the encryption effect of high key ECC.

SFLASH (NESSIE chooses a digital signature scheme (especially for smart card applications and similar applications); Schlumberger (France))

quartz

Password authentication

key authentication

Public key infrastructure

X.509

Public key certificate

Authentication authorization

Certificate revocation list

Identity-based cryptography

Certificate-based encryption

Secure key issuing cryptography

Certificateless cryptography

Anonymous authentication system

GPS (Nishi chooses anonymous authentication scheme; French Higher Teachers College; Post)

Secret key algorithm (also known as symmetric key algorithm)

Stream cipher

A5/ 1, A5/2 (encryption standard specified in GSM mobile phone standard)

BMGL

chameleon

FISH (Siemens)

World War II' Fish' Code

Geheimfernschreiber (the mechanical one-time password of Siemens AG was called sturgeon by Blackley Manor during World War II).

Schlusselzusatz (Lorenz's mechanical one-time secret password during World War II was called [[tunny]] by Blackley Manor.

spiral

ISAAC (used as a pseudo-random number generator)

Leviathan (password)

Lili-128

Mug1(recommended by cryptrec)

Multi-s 01(recommended by cryptrec)

One secret at a time (werner and Mao Bonne, who were patented in the mid-1920s; An extreme stream cipher)

Panama

Dog fish (rose anderson's improvement of fish)

RC4 (ARCFOUR) (one of the series of Professor Ron Rivest at MIT; CRYPTREC is recommended (limited to 128-bit keys).

Ciphersaber (RC4 variant with 10 byte random iv, easy to implement)

Navy Seals

snow

sober

SOBER-t 16

SOBER-t32

wake up

Block cipher

Block cipher operation mode

Product cipher

Feistel cipher (block cipher design mode proposed by Horst Feistel)

Advanced encryption standard (packet length is 128 bits; AES NIST anthology, FIPS197,2001-by Joan Damon and Vincent Riemann; A selection of Loch Ness monsters; Recommended by CRYPTREC)

Anubis (128 bit block)

BEAR (proposed by rose anderson) is a block cipher constructed by stream cipher and hash function.

Blowfish (packet length is 128 bits; Bruce schneier waits)

Camellia (packet length is 128 bits; Ntt&; Mitsubishi electric); Recommended by CRYPTREC)

CAST- 128 (CAST5) (64-bit block; One of a series of algorithms by Carlisle Adams and Stafford Tavares, who insist (in fact, they are firm) that the name is not because of their initials.

CAST-256 (CAST6) (128 bit packet length; One of AES competitors, CAST- 128' s successor)

CIPHERUNICORN-A (packet length is 128 bits; Recommended by CRYPTREC)

CIPHERUNICORN-E (64-bit block; Recommended by CRYPTREC (limited))

Cmea-the password used by American mobile phones was found to be weak.

CS-Cipher (64-bit packet length)

DESzh: number; Zh-tw: Digital Encryption Standard (64-bit packet length; FIPS 46-3， 1976)

Deal- AES candidate algorithm evolved from DES.

DES-X is a variant of DES, which increases the key length.

Fair alloy

GDES is a derivative of DES, which aims to improve the encryption speed.

Grand Cru (128-bit packet length)

HieroCrypt-3 (packet length 128 bits; Recommended by CRYPTREC))

Hierocrypt-L 1 (64-bit packet length; Recommended by CRYPTREC (limited))

International Data Encryption Algorithm (idea) (64-bit packet length-James Messi &; X lai)

Iraqi block cipher (IBC)

KASUMI (64-bit packet length; Based on MISTY 1, used for the next generation of W-CDMA mobile phone security)

KHAZAD (64-bit module designed by Barretto and Rijmen)

Khufu and Ha Fula (64-bit block cipher)

LION (rose anderson), a block cipher constructed by stream cipher and hash function.

LOKI89/9 1 (64-bit block cipher)

Loki97 (cipher with block length of 128 bits, AES candidate)

Lucifer (by Tuchman et al. of IBM, Early1970s; Modified by NSA/NBS and released as DES)

Magenta (AES candidate)

Mars (AES final work, author Don Coppersmith and others)

MISTY 1 (Nishi selects 64-bit blocks; Mitsubishi electric (Japan); Recommended by CRYPTREC (limited))

MISTY2 (packet length is 128 bits: mitsubishi electric (Japan))

Nimbus (64-bit packet)

Noekeon (packet length is 128 bits)

NUSH (variable packet length (64-256 bits))

Q (packet length is 128 bits)

RC2 64-bit packet with variable key length.

RC6 (variable packet length; AES finalist, Ron Rivest et al.)

RC5 (Ron Rivest)

More secure (variable packet length)

SC2000 (packet length is 128 bits; Recommended by CRYPTREC)

Serpent (packet length is 128 bits; AES finalists rose anderson, Eli Beaham, Lars Knudsen)

SHACAL- 1 (256-bit block)

SHACAL-2 (256-bit block cipher; Nishi Selected Gemplus (France))

Shark (grandfather of Rijndael/AES, designed by Damon and Rijmen)

Square (the father of Rijndael/AES, designed by Damon and Rijmen)

3 way (Joan Damon's 96-bit block)

TEA (small encryption algorithm) (by David Wheeler &; Roger Needham)

Triple DES(Walter tuch man, the leader of Lucifer design team-not all triple use of DES increases security, Tuchman did it; CRYPTREC (limited, only used in FIPS publication 46-3) is recommended.

Twofish (packet length is 128 bits; AES Final Works by Bruce Schneier et al.)

XTEA (David Wheeler & Roger Needham)

Multi-table instead of cipher machine password

Enigma (German wheel cipher machine in World War II-there are many variants, most of which have huge user networks)

Purple (the highest level cipher machine in Japanese diplomacy in World War II; Japanese navy design)

SIGABA (World War II American cipher machine, designed by William Friedman and Frank Rolet. )

TypeX (world war ii British cipher machine)

Mixed code/password combination

JN-25 (advanced password of Japanese navy in World War II; There are many variations)

Naval Cypher 3 (30 advanced password of the Royal Navy in 1930s and World War II)

Visual password

Secret password (USA)

Electronic key management system of EKMS national security agency

FNBDT NSA encrypted narrowband voice standard

Fortezza encryption based on PC card format portable encryption token

KW-26 ROMULUS telex encryption machine (1960s- 1980s)

Voice encryption of KY-57 VINSON tactical radio station

SINCGARS code-controlled frequency hopping tactical radio station

STE encrypted telephone

STU-III's old encrypted phone

Storms prevent leaks

1 product

break the code

Passive attack

Select plaintext attack

Selected ciphertext attack

Adaptive selection ciphertext attack

Violent attack

Key length

Unique solution distance

cryptanalysis

Encounter an attack in the middle

Differential cryptanalysis

Linear cryptanalysis

Cryptanalysis of sliding attack

Algebraic cryptanalysis

XSL attack

Modern cryptanalysis

Weak keys and password-based passwords

Violent attack

Dictionary attack

Related key attack

Key derivation function

weak bond

word of command

Key agreement of password authentication

password

salt

Key transmission/exchange

BAN logic

Needham-Schroeder

Ao te Veris

Wide-mouthed frog

Duffy-Herman

Man in the middle attack

Pseudo-random number and true random number generator

PRNG

CSPRNG

Hardware random number generator

Bloom Bloom Shubu

Yarrow (schneier et al.)

Fortuna (waiting for schneier)

Isaac

Pseudo-random number generator based on SHA- 1, INASI X 9.42-2006 54 38+0 annex C. 1 (Cryptrec example).

PRNG is based on sha-1 in FIPS publication 186-2 (inc change notice1) appendix 3. 1 (example of cryptrec).

PRNG revised Sha-1 in Appendix 3. 1 based on FIPS public publication 186-2 (inc change notice1) (Cryptrec example).

Anonymous communication

Dining Password Protocol (David Chom)

Anonymous delivery

pseudonym

Anonymous online banking service

Onion routing

legal question

Cryptography as Free Speech

Bernstein v. USA

DeCSS

Phil Zimmerman

The exit of cryptography

Key escrow and editing chip

digital millennium copyright act

Zh: Digital Rights Management; Zh-tw: Digital Rights Management (DRM)

Cryptography patent

RSA (now in the public domain)

David Chom and Digital Cash

Cryptography and law enforcement

wiretap

spy

Password-related laws in different countries

Official Secrets Act (UK)

Investigation Powers Regulation Act 2000 (United Kingdom)

school term

secret key

encrypt

ciphertext

Announce in writing

Encryption method

tabula rasa

Books and publications

Cryptography related books

Important publications in the field of cryptography

Cryptologist

See list of cryptographers

Application of cryptographic technology

Commitment scheme

Secure multiparty computing

Electronic voting

certificate

digital signature

Cryptographic engineering

cryptography

odds and ends

stratum

spy

IACR

extremist

safety engineering

sigint

write in invisible ink

Cryptologist

Secure sockets layer (SSL)

Quantum cryptography

Secret anarchism

Encrypted surfer

Key escrow

Zero knowledge proof

Random prediction model

Blind signature

Blindness (cryptography)

digital time stamp

Secret * * *

Trusted operating system

Oracle Bone Inscriptions (Cryptography)

Free/open source cryptosystem (especially algorithm+protocol+system design)

PGP (the names of several related encryption systems, some of which are not free software in the GNU sense since the Internet Association obtained this name)

FileCrypt (open source/commercial command line version of PGP from Veridis, Denmark, see PGP)

Gpg (open source implementation of open PGP IETF standard encryption system)

SSH (Secure Shell), which realizes password-protected variants of several common Unix utilities, was originally developed by Tatu Ilonen as open source software in Finland. Now there is OpenSSH, an open source implementation that supports SSH v 1 and SSH v2 protocols. There are also commercial implementations.

IPsec (Internet Protocol Security IETF Standard, an important part of IPv6 IETF Standard)

Free S/WAN (an open source implementation of IPSec)

Other branches of military science

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