Domov technika Encryption Algorithm

# Encryption Algorithm

## Briefintroduction

Accordingtorecords,theancientGreeksinventedthesubstitutioncodein400BC.In1881,theworld'sfirsttelephonesecuritypatentappeared.DuringtheSecondWorldWar,theGermanmilitaryusedthe"Enigma"cryptographicmachine,andcryptographyplayedaveryimportantroleinthewar.

Withthedevelopmentofinformationtechnologyanddigitalsociety,people’sawarenessoftheimportanceofinformationsecurityandconfidentialitycontinuestoincrease,soin1997,theAmericanNationalBureauofStandardsannouncedtheimplementationofthe"AmericanDataEncryptionStandard(DES)"Thecivilforcesbegantofullyinterveneintheresearchandapplicationofcryptography,usingencryptionalgorithmssuchasDES,RSA,andSHA.Asthedemandforencryptionstrengthcontinuestoincrease,AESandECChaverecentlyappeared.

Usingcryptographycanachievethefollowingpurposes:

Dataintegrity:Preventdatafrombeingchanged.

Identityverification:toensurethatthedataissentfromaspecificparty.

## Classification

Encryptiontechnologyisusuallydividedintotwocategories:"symmetric"and"asymmetric".

## Algorithm

AnencryptionsystemScanbedescribedbymathematicalnotationasfollows:

S={P,C,K,E,D}

Amongthem

P——plaintextspace,whichmeansthesetofallpossibleplaintexts,

C——theciphertextspace,meansthesetofallpossibleciphertexts,

p>

K——keyspace,thekeyisavariableparameterintheencryptionalgorithm,

E——encryptionalgorithm,composedofsomeformulas,rulesorprocedures,

D——Decryptionalgorithm,whichistheinverseofE.

WhenthekeykÎKisgiven,therelationshipbetweenthesymbolsisasfollows:

C=Ek(P),theciphertextCisobtainedafterencryptingtheplaintextP

P=Dk(C)=Dk(Ek(P)),theplaintextPisobtainedafterdecryptingtheciphertextC

IfE-1representstheinverseofE,D-1representsDInversely,thereare:

Ek=Dk-1andDk=Ek-1

Therefore,theencryptiondesignmainlydeterminesE,D,K.

## Commonencryptionalgorithms

DES(DataEncryptionStandard):Symmetricalalgorithm,dataencryptionstandard,faster,suitableforencryptinglargeamountsofdata;

3DES(TripleDES):ItisasymmetricalgorithmbasedonDES.Itusesthreedifferentkeystoencryptapieceofdatathreetimes,whichhashigherstrength;

RC2andRC4:symmetricalgorithms,usevariable-lengthkeysEncryptlargeamountsofdata,fasterthanDES;

IDEA(InternationalDataEncryptionAlgorithm)internationaldataencryptionalgorithm,usinga128-bitkeytoprovideverystrongsecurity;

RSA:InventedbyRSA,itisapublickeyalgorithmthatsupportsvariable-lengthkeys.Thelengthofthefileblockthatneedstobeencryptedisalsovariable,anasymmetricalgorithm;thealgorithmisasfollows:

First,findthreeNumber,p,q,r,

Thethreenumbersp,q,rareprivatekeys.

Next,findmsothatrm==1mod(p-1)(q-1).....

Thismmustexist,becauserand(p-1)(q-1)arerelativelyprimeandcanbeobtainedbydividingbytossandturns.

Comeagain,calculaten=pq.......

m,nthesetwonumbersarepublickey

DSA(DigitalSignatureAlgorithm):DigitalsignaturealgorithmisastandardDSS(DigitalSignatureStandard),strictlyspeaking,itisnotanencryptionalgorithm;

BLOWFISH,itusesavariable-lengthkeywithalengthofupto448bits,andrunsveryfast;

SSF33,SSF28,SCB2(SM1):ThehiddenandundisclosedcommercialalgorithmsoftheNationalCryptographyBureau,whichareusedindomesticcivilandcommercialapplications,exceptthesearenotallowedtobeused,otherscanbeused;

p>

## Otheralgorithms

SuchasElGamal,Diffie-Hellman,newellipticcurvealgorithmECC,etc.

## Typesofencryptionalgorithms

Intoday'sinformationsecurityfield,therearevariousencryptionalgorithmsthatcondensethewisdomofcomputerscientists.Fromamacropointofview,theseencryptionalgorithmscanbesummarizedintothreecategories:hashingalgorithms,symmetricencryptionalgorithms,asymmetricencryptionalgorithm.

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