Avaintenhallinta

Mainperformance

Keymanagementincludesallaspectsfromkeygenerationtokeydestruction.Mainlymanifestedinthemanagementsystem,managementagreementandkeygeneration,distribution,replacementandinjection,etc.Formilitarycomputernetworksystems,duetousermobility,affiliationandcoordinatedcombatcommandarecomplicated,higherrequirementsareputforwardforkeymanagement.

Prosessi

Avainten luominen

Avaimenpituuden pitäisi olla tarpeeksi pitkä.Yleensä mitä suurempiavaimenpituus,suurimpivastaava avaintila ja sitä vaikeampi on hyökkääjän käyttää salasanojen arvaamista.

Chooseagoodkeyandavoidweakkeys.Therandombitstringgeneratedbytheautomaticprocessingdeviceisagoodkey.Whenchoosingakey,youshouldavoidchoosingaweakkey.

Forpublickeycryptosystems,keygenerationismoredifficultbecausethekeymustsatisfycertainmathematicalcharacteristics.

Keygenerationcanbeachievedthroughonlineorofflineinteractivenegotiation,suchascryptographicprotocols.

Keydistribution

Theuseofsymmetricencryptionalgorithmsforconfidentialcommunicationrequiresthesharingofthesamekey.Usually,amemberofthesystemselectsasecretkeyfirst,andthentransmitsittoanothermemberorothermembers.TheX9.17standarddescribestwotypesofkeys:keyencryptionkeysanddatakeys.Thekeyencryptionkeyencryptsotherkeysthatneedtobedistributed;whilethedatakeyonlyencryptstheinformationflow.Thekeyencryptionkeyisgenerallydistributedmanually.Toenhanceconfidentiality,thekeycanalsobedividedintomanydifferentpartsandthensentoutondifferentchannels.

Vahvistusavain

Avain lähetetään, ja siihen on liitetty joitakin virheentunnistus- tai virheenkorjausbittejä. Kun avain onvirhelähetyksessä, se voidaan helposti kuitata ulos, ja tarvittaessa avain voidaan lähettää uudelleen.

Thereceivingendcanalsoverifywhetherthereceivedkeyiscorrect.Thesenderencryptsaconstantwiththekey,andthensendsthefirst2-4bytesoftheciphertexttogetherwiththekey.Atthereceivingend,dothesamework.Ifthedecryptedconstantatthereceivingendcanmatchtheconstantatthesendingend,thetransmissioniserror-free.

Updatingthekey

Whenthekeyneedstobechangedfrequently,itisindeeddifficulttodistributethenewkeyfrequently.Aneasiersolutionistochangethekeyfromtheoldone.Anewkeyisgeneratedfromthekey,sometimescalledakeyupdate.Youcanuseaone-wayfunctiontoupdatethekey.Ifbothpartiessharethesamekeyandoperatewiththesameone-wayfunction,thesameresultwillbeobtained.

Avainten tallennus

Avaimet voidaan tallentaa aivoihin,magneettiraitakortti,älykortti.Avain voidaan myös jakaa kahteen osaan, puolikas tallennetaan liittimeen ja toinen ontallennettu ROM-avaimeen.Voidaan myös käyttää samanlaisia ​​menetelmiäsalaukseen ja salausavaimeen.

Varmuuskopiointiavain

Avainvarmistukseen voidaan käyttää avaimenperää, salausjakoa, salaisuuksien jakamista jne.

Theeasiestwayistouseakeyescrowcenter.Keyescrowrequiresalluserstohandovertheirkeystothekeyescrowcenter,andthekeyescrowcenterbacksupandkeepsthekeys(suchaslockedinasafesomewhereorencryptedandstoredwiththemasterkey),Oncetheuser'skeyislost(suchastheuserforgetsthekeyortheuseraccidentallydies),inaccordancewithcertainrulesandregulations,theuser'skeycanbeobtainedfromthekeyescrowcenter.Anotherbackupsolutionistousesmartcardsastemporarykeyescrow.Forexample,Alicestoresthekeyinthesmartcard,andgivesittoBobwhenAliceisaway.BobcanusethecardtodoAlice'swork.WhenAlicereturns,Bobreturnsthecard.Becausethekeyisstoredinthecard,BobIdon'tknowwhatthekeyis.

Secretdivisiondividesthesecretintomanypieces.Eachpiecedoesnotmeananything,butwhenthesepiecesareputtogether,thesecretwillbereproduced.

Paremminkäytä salaisuuksienjakoprotokollaa.JaakeyKintonblocks,jakaista osistakutsutaan "varjokseen".Tiedessään lisää lohkoja voi laskeaavaimenK,tietäen,ettäym-1 tai vähemmän lohkojaei voida laskeaAvainK,jokakutsutaan(m,n)kolmeksi menetelmä, projektigeometria, lineaarialgebra, SunTzutheorem jne.

Lagrangin interpolaatiopolynomijärjestelmä on helposti ymmärrettävä salaisuuksien jakamisen (m,n) kynnysjärjestelmä.

Secretsharingsolvestwoproblems:first,ifthekeyisaccidentallyorintentionallyexposed,theentiresystemisvulnerabletoattack;second,ifthekeyislostordamaged,allinformationinthesystemcannotbeused.

Keyvalidityperiod

Encryptionkeyscannotbeusedindefinitely.Thereareseveralreasons:thelongerthekeyisused,thegreaterthechanceofitbeingleaked;ifthekeyisHasbeenleaked,thenthelongerthekeyisused,thegreatertheloss;thelongerthekeyisused,thegreaterthetemptationforpeopletospendenergydecipheringit-evenbruteforceattacks;formultipleciphertextsencryptedwiththesamekeyItisgenerallyeasiertoperformcryptanalysis.

Differentkeysshouldhavedifferentvalidityperiods.

Thevalidityperiodofthedatakeymainlydependsonthevalueofthedataandtheamountofencrypteddatainagiventime.Thegreaterthevalueandthedatatransferrate,themorefrequentlythekeysusedwillbereplaced.

Keyencryptionkeysdonotneedtobechangedfrequently,becausetheyareonlyusedoccasionallyforkeyexchange.Insomeapplications,thekeyencryptionkeyisonlychangedonceamonthorayear.

Theencryptionkeyusedtoencryptthesaveddatafilecannotbechangedfrequently.Usuallyeachfileisencryptedwithauniquekey,andthenallkeysareencryptedwithakeyencryptionkey.Thekeyencryptionkeyiseithermemorizedorstoredinasafeplace.Ofcourse,losingthiskeymeanslosingallfileencryptionkeys.

Thevalidityperiodoftheprivatekeyinthepublickeycryptographyapplicationvariesaccordingtotheapplication.Theprivatekeyusedfordigitalsignatureandidentificationmustlastforseveralyears(orevenlife),andtheprivatekeyusedforthecointossprotocolshouldbedestroyedimmediatelyaftertheagreementiscompleted.Evenifthesecurityofthekeyisexpectedtolastforalifetime,itisnecessarytoconsiderchangingthekeyonceeverytwoyears.Theoldkeystillneedstobekeptsecretincasetheuserneedstoverifytheprevioussignature.Butthenewkeywillbeusedtosignthenewfiletoreducethenumberofsignaturefilesthatacryptanalystcanattack.

Tuhoa avain

Jos avain on vaihdettava, vanha avain on tuhottava ja avain on tuhottava fyysisesti.

Hallintajärjestelmä

Julkisen avaimen salasanan avulla on helpompi hallita. Riippumatta siitä, kuinka monta ihmistä verkossa on, jokaisella on vain yksi julkinen avain.

Itisnotenoughtouseapublic/privatekeypair.Theimplementationofanygoodpublickeycryptographyneedstoseparatetheencryptionkeyfromthedigitalsignaturekey.Butasinglepairofencryptionandsigningkeysisnotenough.LikeanIDcard,aprivatekeyprovesarelationship,andpeoplehavemorethanonerelationship.Forexample,Alicecansignadocumentinthenameofaprivateperson,thevicepresidentofthecompany,etc.

InthefinancialICcardjointpilotprojectsofcommercialbanks,thesecuritycontrolandmanagementofkeysbybanksatalllevelsisthekeytothesecurityoftheapplicationsystem.

"RT-KMSKeyManagementSystem" noudattaa"ChinaFinancial Integrated Circuit(IC)CardSpecification"(v1.0)"ja"BankICCardJointPilotTechnicalPlan"jäsenpankkien riippumattomuuden helpottamiseksi.

Korttien myöntäminen, kortinlukijoiden jakamisen toteuttaminen ja pankkien välisten tapahtumien suorittaminen eri paikoissa.

Securitymechanism

InthenationalbankICcardjointpilotprogram,banksatalllevelsusekeymanagementsystemstoimplementkeysecuritymanagement.Thekeymanagementsystemadoptsthe3DESencryptionalgorithmandusesthethree-levelmanagementsystemofthebankheadoffice,theregionalbranchofthePeople’sBankofChina(commercialbankheadoffice),andmemberbankstosecurelysharethepublicmasterkeyandrealizecardintercommunication.,Equipmentsharing.

Theentiresecuritysystemstructuremainlyincludesthreetypesofkeys:thenationally-usedconsumer/cashwithdrawalmasterkeyGMPKoftheheadoffice,theconsumption/cashwithdrawalmasterkeyMPKoftheissuingbank,andothersoftheissuingbank

Masterkey. Avaimen tarkoituksen mukaan järjestelmä ottaa käyttöön erilaisia ​​käsittelystrategioita.

Suunnitteluperiaatteet

(1)Kaikki avaimet ladataan ja tuodaan salatekstinä.

(2)Avain koskee viranomaisenvalvontaa, ja eri organisaatioilla tai henkilökunnalla on eri valtuudet lukea, kirjoittaa, päivittää ja käyttää erilaisia ​​avaimia.

(3)Inordertoensurethesecurityofkeyuseandconsidertheneedsofactualuse,thesystemcangeneratemultiplesetsofmasterkeys.Ifoneofthekeysisleakedorattacked,theapplicationsystemcanbestoppedimmediatelyTheuseofthissetofkeysandtheuseofbackupkeys,soastoavoidthewasteofexistinginvestmentandequipmentasmuchaspossible,andreducetheriskofsystemuse.

(4)Userscanchoosedifferentcombinationsandconfigurationsofthekeymanagementsubsystemaccordingtoactualneeds.

(5)Avainpalvelu,tallennus- ja varmuuskopiointiavaimensalauskoneen muodossa.

Managementtechnology

Technologyclassification

1.Symmetrickeymanagement.Symmetricencryptionisrealizedbasedonthecommonkeepingofsecrets.Bothpartiestothetradethatadoptsymmetricencryptiontechnologymustensurethattheyusethesamekey,thattheexchangeofeachother'skeysissafeandreliable,andalsosetupprocedurestopreventkeyleakageandchangekeys.Inthisway,themanagementanddistributionofsymmetrickeyswillbecomeapotentiallydangerousandcumbersomeprocess.Therealizationofsymmetrickeymanagementthroughpublickeyencryptiontechnologymakesthecorrespondingmanagementsimplerandmoresecure,andatthesametimesolvesthereliabilityandauthenticationproblemsinthepuresymmetrickeymode.Thetradingpartycangenerateauniquesymmetrickeyforeachexchangeofinformation(suchaseachEDIexchange)andencryptthekeywithapublickey,andthenencrypttheencryptedkeywiththekeyTheinformation(suchasEDIexchange)issenttothecorrespondingtradingpartytogether.Sinceauniquekeyisgeneratedforeachinformationexchange,eachtradingpartynolongerneedstomaintainthekeyandworryabouttheleakageorexpirationofthekey.Anotheradvantageofthismethodisthatevenifakeyisleaked,itwillonlyaffectonetransaction,andwillnotaffectallthetransactionrelationshipsbetweenthetradingparties.Thismethodalsoprovidesasecurewaytoissuesymmetrickeysbetweentradingpartners.

2.Publickeymanagement/digitalcertificate.Digitalcertificates(publickeycertificates)canbeusedtoexchangepublickeysbetweentradingpartners.ThestandardX.509developedbytheInternationalTelecommunicationUnion(ITU)definesdigitalcertificates.ThisstandardisequivalenttotheISO/IEC9594-8:195standardjointlyissuedbytheInternationalOrganizationforStandardization(ISO)andtheInternationalElectrotechnicalCommission(IEC).Digitalcertificatesusuallyincludethenamethatuniquelyidentifiestheownerofthecertificate(ie,thetradingparty),thenamethatuniquelyidentifiesthecertificateissuer,thepublickeyofthecertificateowner,thedigitalsignatureofthecertificateissuer,thevalidityperiodofthecertificate,andtheserialnumberofthecertificate,etc..Thecertificateissuerisgenerallycalledacertificateauthority(CA),whichisanorganizationtrustedbyallpartiesinthetrade.Digitalcertificatescanplayaroleinidentifyingtradingpartiesandarecurrentlyoneofthetechnologieswidelyusedine-commerce.

3.Standardspecificationsrelatedtokeymanagement.Atpresent,relevantinternationalstandardizationorganizationshavestartedtoformulatetechnicalstandardsandspecificationsonkeymanagement.TheInformationTechnologyCommittee(JTC1)underISOandIEChasdraftedaninternationalstandardspecificationforkeymanagement.Thespecificationismainlycomposedofthreeparts:oneisthekeymanagementframework;thesecondisthemechanismusingsymmetrictechnology;thethirdisthemechanismusingasymmetrictechnology.Thespecificationhasnowenteredthestageofvotingondraftinternationalstandardsandwillsoonbecomeanofficialinternationalstandard.

Digitaalinen allekirjoitus

Digitalsignatureisanothertypeofapplicationofpublickeyencryptiontechnology.Itsmainmethodis:thesenderofthemessagegeneratesa128-bithashvalue(ormessagedigest)fromthemessagetext.Thesenderusesitsownprivatekeytoencryptthishashvaluetoformthesender'sdigitalsignature.Then,thisdigitalsignaturewillbesenttotherecipientofthemessageasanattachmenttothemessagetogetherwiththemessage.Thereceiverofthemessagefirstcalculatesa128-bithashvalue(ormessagedigest)fromthereceivedoriginalmessage,andthenusesthesender'spublickeytodecryptthedigitalsignatureattachedtothemessage.Ifthetwohashvalues​​arethesame,thereceivercanconfirmthatthedigitalsignatureisfromthesender.Throughthedigitalsignature,theauthenticationandnon-repudiationoftheoriginalmessagecanberealized.

ISO/IECJTC1isalreadydraftingrelevantinternationalstandards.Thepreliminarytitleofthestandardis"InformationTechnologySecurityTechnologywithAttachedDigitalSignatureScheme",whichconsistsoftwoparts:anoverviewandanidentity-basedmechanism.

Salausalgoritmi

Johdatus salaukseenTietueiden mukaan vuonna 400 eKr. muinaiset kreikkalaiset keksivätvaihtosalauksen. Vuonna 1881 maailman ensimmäinen puhelinturvapatentti ilmestyi.

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

Usingcryptographycanachievethefollowingpurposes:

Luottamuksellisuus: Estä käyttäjän tunnistaminen tai tietojen lukeminen.

Tietojen eheys: Estä tietojen muuttaminen.

Identiteettivarmennus: varmistaaksesi, että tiedot ovat tietystä osapuolesta peräisin.

2.IntroductiontoencryptionalgorithmsAccordingtodifferentkeytypes,moderncryptographictechnologiesaredividedintotwocategories:symmetricencryptionalgorithms(secretkeyencryption)andasymmetricencryptionalgorithms(publickeyencryption).

Thesymmetrickeyencryptionsystemusesthesamesecretkeyforencryptionanddecryption,andbothpartiesincommunicationmustobtainthiskeyandkeepthekeysecret.

Epäsymmetrisen avaimen salausjärjestelmän käyttämät salausavain (julkinen avain) ja salauksenpurkuavain (yksityinen avain) ovat erilaisia.

Symmetricencryptionalgorithm

Inasymmetricencryptionalgorithm,onlyonekeyisusedtoencryptanddecryptinformation,thatis,thesamekeyisusedforencryptionanddecryption.Commonlyusedalgorithmsinclude:DES(DataEncryptionStandard):adataencryptionstandard,whichisfasterandissuitableforencryptinglargeamountsofdata.

3DES(TripleDES):Perustuu DES:iin,joukko tietoja salattu kolme kertaa kolmella eri avaimella, vahvemmalla.

AES (Advanced Encryption Standard): Advanced Encryption Standard, sen jälkeen seuraavan sukupolven salausalgoritmistandardi, nopealla nopeudella ja korkealla suojaustasolla;

InOctober2000,NIST(AmericanNationalStandardAndTechnologyAssociation)announcedtheadoptionofanewkeyencryptionstandardselectedfrom15candidatealgorithms.RijndaelwasselectedasthefutureAES.Rijndaelwasfoundedinthesecondhalfof1999byresearchersJoanDaemenandVincentRijmen.AESisincreasinglybecomingthedefactostandardforencryptingvariousformsofelectronicdata.

National Institute of StandardsandTechnology (NIST) muotoili uuden Advanced Encryption Standard (AES) -spesifikaation 26. toukokuuta 2002.

AlgorithmprincipleTheAESalgorithmisbasedonpermutationandpermutationoperations.Permutationistorearrangedata,andreplacementistoreplaceonedataunitwithanother.AESusesseveraldifferentmethodstoperformpermutationandpermutationoperations.

AESisaniterative,symmetrickeyblockcipher,itcanuse128,192,and256-bitkeys,anduse128-bit(16-byte)blockstoencryptanddecryptdata.Unlikepublickeyciphersthatusekeypairs,symmetrickeyciphersusethesamekeytoencryptanddecryptdata.Thenumberofbitsoftheencrypteddatareturnedbytheblockcipheristhesameastheinputdata.Iterativeencryptionusesaloopstructureinwhichtheinputdataisrepeatedlyreplacedandreplaced.

AES:n ja 3DES:n vertailu

Epäsymmetrinen goritmi

Yleiset symmetriset salausalgoritmit ovat seuraavat:

RSA:InventedbyRSA,itisapublickeyalgorithmthatsupportsvariable-lengthkeys.Thelengthofthefileblockthatneedstobeencryptedisalsovariable;

p>

DSA(Digitaalinen allekirjoitusalgoritmi):Digitaalinen allekirjoitusalgoritmi,on standardiDSS(Digital Signature Standard);

ECC(EllipticCurvesCryptography):EllipticCurvesCryptography.

In1976,becausesymmetricencryptionalgorithmscouldnolongermeettheneeds,DiffieandHellmanpublishedanarticlecalled"NewTrendsinCryptography",whichintroducedtheconceptofpublickeyencryption.AdelmanproposedtheRSAalgorithm.

Withtheprogressandimprovementofthemethodofdecomposinglargeintegers,theincreaseofcomputerspeedandthedevelopmentofcomputernetworks,inordertoensurethesecurityofdata,theRSAkeyneedstoincreasecontinuously.However,theincreaseofthekeylengthleadstoAsthespeedofencryptionanddecryptionhasbeengreatlyreduced,hardwareimplementationhasbecomemoreandmoreunbearable,whichhasbroughtaheavyburdentoapplicationsthatuseRSA,soanewalgorithmisneededtoreplaceRSA.

In1985,N.KoblitzandMillerproposedtheuseofellipticcurvesincryptographicalgorithms,basedonthediscretelogarithmproblemECDLPinpointgroupsonellipticcurvesoverfinitefields.ECDLPisamoredifficultproblemthanthefactorizationproblem,itisexponentiallydifficult.

Principle-thedifficultproblemontheellipticcurveThediscretelogarithmproblemontheellipticcurveECDLPisdefinedasfollows:GivenaprimenumberpandanellipticcurveE,forQ=kP,findPandQFindapositiveintegerkthatislessthanp.ItcanbeprovedthatitiseasiertocalculateQfromkandP,butitismoredifficulttocalculatekfromQandP.

Correspondingtheadditionoperationintheellipticcurvetothemodularmultiplicationoperationinthediscretelogarithm,andthemultiplicationoperationintheellipticcurvecorrespondingtothemodularexponentiationoperationinthediscretelogarithm,wecanbuildbasedonThecorrespondingcryptosystemoftheellipticcurve.

Forexample,correspondingtotheDiffie-Hellmanpublickeysystem,wecanimplementitontheellipticcurveinthefollowingway:selectthegeneratorPonE,andrequireenoughgroupelementsgeneratedbyP,andthecommunicationpartiesAAndBselectsaandbrespectively,aandbarekeptsecret,butaPandbParemadepublic,andthekeyusedforcommunicationbetweenAandBisabP,whichisnotknowntoathirdparty.

ThecorrespondingELGamalcryptosystemcanbeimplementedontheellipticcurveinthefollowingway:

Upota yksinkertainen teksti PmpointonE:hen, valitse kohta B∈E ja jokainen käyttäjäValitse kokonaisluku,0

K=kG[missäK,GarepointsonEp(a,b),jakisanintegerlessthann(pisteenG nisojärjestys)]

ItisnotdifficulttofindthatgivenkandG,itiseasytocalculateKaccordingtotheruleofaddition;butgivenKandG,itisrelativelydifficulttofindk.

Tämä on elliptisen käyrän salausalgoritmin aiheuttama ongelma.Kutsumme pistettä Gperuspiste, k(yksityinen avain)jaKjulkinen avain.

ComparisonofECCandRSAComparedwithECCandRSA,Hasabsoluteadvantagesinmanyaspects,mainlyreflectedinthefollowingaspects:

Vahva hyökkäyksen vastainen. Sama avaimenpituus, sen hyökkäysvastaisuus on aina vahvempi.

Theamountofcalculationissmallandtheprocessingspeedisfast.TheoverallspeedofECCismuchfasterthanthatofRSAandDSA.

Thestoragespaceissmall.ThekeysizeandsystemparametersofECCaremuchsmallerthanthoseofRSAandDSA.More,itmeansthatitoccupiesamuchsmallerstoragespace.ThisisofspecialsignificancefortheapplicationofencryptionalgorithmsonICcards.

Lowbandwidthrequirements.WhenencryptinganddecryptinglongmessagesAtthistime,thethreetypesofcryptosystemshavethesamebandwidthrequirements,butwhenappliedtoshortmessages,theECCbandwidthrequirementsaremuchlower.ThelowbandwidthrequirementsmakeECChaveawiderangeofapplicationprospectsinthefieldofwirelessnetworks.

ECCThesecharacteristicsmakeitsuretoreplaceRSAandbecomeageneralpublickeyencryptionalgorithm.Forexample,thecreatorsoftheSETprotocolhaveadopteditasthedefaultpublickeyencryptionalgorithminthenextgenerationSETprotocol.

ThefollowingtwoRepresentsthecomparisonofthesecurityandspeedofRSAandECC.

RSA- ja ECC-turvamoduulien vertailu

RSA:n ja ECC:n välinen nopeusvertailu

Hashalgorithm

Hashingalgorithmisalsocalledhashalgorithm,EnglishisHash,whichistotransformaninputofanylength(alsocalledpre-image,pre-image)intoafixed-lengthoutputthroughahashingalgorithm.Theoutputisthehashvalue.Thisconversionisacompressionmapping,thatis,thehashvaluespaceisusuallymuchsmallerthantheinputspace,differentinputsmaybehashedintothesameoutput,anditisimpossibletouniquelydeterminetheinputvaluefromthehashvalue.Simplyput,itisafunctionthatcompressesmessagesofanylengthtoafixed-lengthmessagedigest.

HASHismainlyusedinencryptionalgorithmsinthefieldofinformationsecurity.Itconvertsinformationofdifferentlengthsintomessy128-bitcodes.Thesecodedvalues​​arecalledHASHvalues.ItcanalsobesaidthathashistofindakindofThehashofthemappingrelationshipbetweenthedatacontentandthedatastorageaddressistherefinementoftheinformation,anditslengthisusuallymuchsmallerthanthatoftheinformation,anditisafixedlength.Astrongencryptionhashmustbeirreversible,whichmeansthatnopartoftheoriginalinformationcanbederivedfromthehashresult.Anychangeintheinputinformation,evenifitisonlyonebit,willcauseasignificantchangeinthehashresult,whichiscalledtheavalancheeffect.Hashingshouldalsobeanti-collision,thatis,twopiecesofinformationwiththesamehashresultcannotbefound.Thehashresultwiththesecharacteristicscanbeusedtoverifywhethertheinformationhasbeenmodified.

Yksisuuntaista hash-toimintoa käytetään yleensä luomaan viestitiivisteitä, avaimen salausta jne.Yleiset ovat:

MD5(MessageDigestAlgorithm5): Sen on kehittänyt RSADataSecurityCorporationOone-way-halgorithm.

SHA(SecureHash Algorithm):Se voi luoda 160 bitin arvon datan pituuden;

In1993,theSecureHashAlgorithm(SHA)wasadoptedbytheAmericanNationalStandardItwasproposedbytheInstituteofTechnologyandTechnology(NIST)andpublishedastheFederalInformationProcessingStandard(FIPSPUB180);in1995,arevisedversionofFIPSPUB180-1wasreleased,usuallycalledSHA-1.SHA-1isbasedontheMD4algorithm,anditsdesignlargelyimitatesMD4.Itisnowrecognizedasoneofthesafesthashingalgorithmsandiswidelyused.

PrincipleSHA-1isadataencryptionalgorithm.Theideaof​​thealgorithmistoreceiveapieceofplaintextandthenconvertitintoapieceof(usuallysmaller)ciphertextinanirreversibleway.ItcanalsobesimpleTheunderstandingofistheprocessoftakingastringofinputcodes(calledpre-mappingorinformation)andconvertingthemintoashort-length,fixed-digitoutputsequencethatisahashvalue(alsoknownasinformationdigestorinformationauthenticationcode).

Thesecurityoftheone-wayhashfunctionliesinitsstrongone-wayoperationintheprocessofgeneratingthehashvalue.Ifthepasswordisembeddedintheinputsequence,noonecangeneratethecorrecthashvaluewithoutknowingthepassword,thusensuringitssecurity.SHAdividestheinputstreamintoblocksof512bits(64bytes)perblock,andproduces20bytesofoutputcalledthemessageauthenticationcodeormessagedigest.

Algoritmin syöttöviestin enimmäispituus ei ylitä 264 bittiä, ja tuotettu ulostulo on 160-bittinen viestitiiviste.Syöte käsitellään 512-bittisissä ryhmissä.SHA-1 on palautumaton, törmäyksenesto ja sillä on hyvä vaikutus.

Thedigitalsignaturecanberealizedthroughthehashalgorithm.Theprincipleofdigitalsignatureistoconverttheplaintexttobetransmittedintoamessagedigestthroughafunctionoperation(Hash)(differentplaintextcorrespondstodifferentmessagedigests),Themessagedigestisencryptedandsenttotherecipienttogetherwiththeplaintext.Therecipientwillgenerateanewmessagedigestofthereceivedplaintextandcompareitwiththesender'ssentmessagedigest.Thecomparisonresultisconsistent,indicatingthattheplaintexthasnotbeenchanged.Ifitisinconsistent,itmeansTheplaintexthasbeentamperedwith.

MAC(InformationAuthenticationCode)isahashresult.Partoftheinputinformationisapassword.OnlyparticipantswhoknowthispasswordcanrecalculateandverifythevalidityoftheMACcode.ThegenerationofMACisshowninthefigurebelow.

SHA-1:n ja MD5:n vertailu, koska molemmat ovat peräisin MD4:stä ja SHA-1:stä ja MD5:stä eroavat toisistaan.yhdennäköisyys.

Securityagainstforcedsupply:ThemostsignificantandimportantdifferenceisthattheSHA-1abstractislongerthantheMD5abstract32bits.Usingforcetechnology,thedifficultyofgeneratinganymessagesothatitsdigestisequaltoagivendigestisa2-orderoperationforMD5,anda2-orderoperationforSHA-1.Inthisway,SHA-1hasgreaterstrengthagainstforcedattacks.

Salausanalyysin turvallisuus: MD5:n suunnittelun vuoksi se on alttiina salausanalyysihyökkäyksille, ja SHA-1 ei ole alttiina sellaisille keskusteluhyökkäyksille.

Nopeus: Samalla laitteistolla SHA-1 toimii hitaammin kuin MD5.

Kahden vertailu

Symetrian ja symmetristen goritmien vertailu

Theprinciplesofthetwoencryptionmethodsaresummarizedabove.Generallyspeaking,therearemainlythefollowingaspectsDifferent:

1.Intermsofmanagement:thepublickeycryptographicalgorithmonlyneedslessresourcestoachieveitspurpose.Inthedistributionofkeys,thereisanexponentialleveldifferencebetweenthetwo(oneisnoneIsn).Therefore,theprivatekeycryptographicalgorithmisnotsuitablefortheuseofWAN,andmoreimportantly,itdoesnotsupportdigitalsignatures.

2.Intermsofsecurity:Sincethepublickeycryptographicalgorithmisbasedonanunsolvedmathematicalproblem,itisalmostimpossibletocrack.Fortheprivatekeycryptographicalgorithm,althoughitisimpossibletocracktheoreticallybyAES,fromtheperspectiveofcomputerdevelopment.Thepublickeyismoreadvantageous.

3.Fromthepointofviewofspeed:ThesoftwareimplementationspeedofAEShasreachedseveralmegabitsortensofmegabitspersecond.Itis100timesthepublickey.Ifimplementedbyhardware,thisratiowillbeexpandedto1000times.

ThechoiceofencryptionalgorithmThepreviouschaptershaveintroducedsymmetricdecryptionalgorithmsandasymmetricencryptionalgorithms.Manypeoplearewondering:Sowhichoneshouldweuseinactualuseisbetter?

Weshoulddetermineaccordingtoourowncharacteristics.Sincetherunningspeedofasymmetricencryptionalgorithmismuchslowerthanthatofsymmetricencryptionalgorithm,whenweneedtoencryptalargeamountofdata,itisrecommendedtousesymmetricencryptionalgorithmtoimproveEncryptionanddecryptionspeed.

Symmetricencryptionalgorithmcannotrealizesignature,sosignaturecanonlybeasymmetricalgorithm.

Asthekeymanagementofthesymmetricencryptionalgorithmisacomplexprocess,themanagementofthekeydirectlydeterminesitssecurity,sowhentheamountofdataissmall,wecanconsiderusinganasymmetricencryptionalgorithm.

Intheactualoperationprocess,weusuallyadoptthemethod:useanasymmetricencryptionalgorithmtomanagethekeyofthesymmetricalgorithm,andthenusethesymmetricencryptionalgorithmtoencryptthedata,sothatwehaveintegratedtwotypesofencryptionalgorithmsTheadvantageofnotonlyrealizestheadvantagesoffastencryptionspeed,butalsorealizestheadvantagesofsafeandconvenientkeymanagement.

Jos salausalgoritmi ei ole valittu, kuinka monta bittiä avainta tulisi käyttää?Yleensä mitä pidempi avain, sitä hitaampi käyntinopeus.Se tulisi valita sen tietoturvatason mukaan, jota todella tarvitsemme.Yleensä 1024-bittistä numeroa suositellaan.

Themodernapplicationofcryptography,withthepopularizationofcommercialapplicationsofcryptography,publickeycryptographyhasreceivedunprecedentedattention.Inadditiontotraditionalcryptographicapplicationsystems,thePKIsystemisbasedonpublickeycryptography,providingfunctionssuchasencryption,signature,authentication,keymanagement,anddistribution.

Confidentialcommunication:Confidentialcommunicationisthecauseofcryptography.Whenusingpublicandprivatekeycryptographyforconfidentialcommunication,therecipientoftheinformationcandecrypttheinformationonlyifheknowsthecorrespondingkey.

Digitalsignature:Digitalsignaturetechnologycanreplacetraditionalhandwrittensignatures,andfromasecurityperspective,digitalsignatureshaveagoodanti-counterfeitingfunction.Ithasawiderangeofapplicationenvironmentsingovernmentagencies,militaryfields,andcommercialfields.

Secretsharing:Secretsharingtechnologyreferstotheuseofcryptographictechniquestosplitasecretinformationintonpiecesofinformationcalledsharingfactors,anddistributethemtonmembers,onlyk(k≤n)legalmembersThesecretinformationcanberecoveredbythesharingfactorof,andanyoneorm(m≤k)memberscooperateswithoutknowingthesecretinformation.Theuseofsecretsharingtechnologycancontrolanysecretinformation,commands,etc.thatneedtobecontrolledbymultiplepeople.

Authenticationfunction:transmitsensitiveinformationonopenchannels,usesignaturetechnologytoverifytheauthenticityandintegrityofthemessage,andverifytheidentityofthecommunicationsubjectbyverifyingthepublickeycertificate.

Keymanagement:Thekeyisamorefragileandimportantlinkinthesecuritysystem.Thepublickeycryptosystemisapowerfultooltosolvethekeymanagementwork;thepublickeycryptosystemisusedforkeynegotiationandgeneration,Thetwopartiesinconfidentialcommunicationdonotneedtosharesecretinformationinadvance;publickeycryptosystemsareusedforkeydistribution,protection,keyescrow,andkeyrecovery.

Basedonthepublickeycryptosystem,inadditiontotheabovegeneralfunctions,thefollowingsystemscanalsobedesignedandimplemented:securee-commercesystem,electroniccashsystem,electronicelectionsystem,electronicbiddingsystem,electroniclotterysystem,etc.

Theemergenceofthepublickeycryptosystemisthebasisforthedevelopmentofcryptographyfromthetraditionalgovernment,militaryandotherapplicationfieldstocommercialandcivilianuse.Atthesametime,thedevelopmentoftheInternetande-commercehasopenedupabroaderfieldforthedevelopmentofcryptography.prospect.

ThefutureofencryptionalgorithmsWiththeimprovementofcalculationmethods,theaccelerationofcomputeroperationspeed,andthedevelopmentofnetworks,moreandmorealgorithmshavebeencracked.

Atthe2004InternationalConferenceonCryptography(Crypto'2004),ProfessorWangXiaoyunfromShandongUniversity,China,madeareportondecipheringMD5,HAVAL-128,MD4andRIPEMDalgorithms,whichmadethepresentinternationaltoppasswordsAcademicexpertsareshocked,whichmeansthatthesealgorithmswillbeeliminatedfromtheapplication.Subsequently,SHA-1wasalsodeclaredtohavebeencracked.

TherearethreeattackexperimentsthathaveanimpactonDESinhistory.In1997,using70,000computersfromvariouscountriesatthattime,ittook96daystocracktheDESkey.In1998,theElectronicFrontierFoundation(EFF)usedaspecialcomputerbuiltfor$250,000tocracktheDESkeyin56hours.In1999,EFFcompletedthecrackingworkin22hoursand15minutes.therefore.DES,whichoncemadeoutstandingcontributions,cannolongermeetourgrowingneeds.

Recently,agroupofresearcherssuccessfullydecomposeda512-bitintegerandannouncedtheRSAcracking.

Wesaythatdatasecurityisrelative.Itcanbesaidthatitissafeforacertainperiodoftimeandundercertainconditions.Withthedevelopmentofhardwareandnetwork,ortheemergenceofanotherWangXiaoyun,thecurrentcommonlyusedencryptionalgorithmsareItmaybecrackedinashorttime.Atthattime,wehavetouselongerkeysormoreadvancedalgorithmstoensuredatasecurity.Therefore,encryptionalgorithmsstillneedtobecontinuouslydevelopedandimprovedtoprovidehigherencryptionsecuritystrengthandcalculatingspeed.

Overviewofthesetwoalgorithms,oneisfromDESto3DEStoAES,andtheotherisfromRSAtoECC.Itsdevelopmentangleisallconsideringthesimplicityofthekey,thelowcost,theeaseofmanagement,thecomplexityofthealgorithm,thesecurityofconfidentiality,andthespeedofcalculation.Therefore,thedevelopmentofalgorithmsinthefuturemustbebasedontheseperspectives,andthesetwoalgorithmsareoftencombinedinactualoperations,andanewalgorithmthatcombinestheadvantagesofthetwoalgorithmswillappearinthefuture.Atthattime,therealizationofe-commercewillsurelybefasterandsafer.