Encryptionalgorithm
Inellipticcurveencryption(ECC),aspecialformofellipticcurveisused,thatis,anellipticcurvedefinedinafinitefield.Theequationisasfollows:
y²=x³+ax+b(modp)
Herepisaprimenumber, andbaretwonon-negativeintegerslessthanp. Theysatisfy:
4a³+27b²(modp)≠0wherex,y,a,b∈Fp, punctum (x, y) satisfacit formulae(2)andaninfinitepointOformanellipseCurveE.
TheellipticcurvediscretelogarithmproblemECDLPisdefinedasfollows:GivenaprimenumberpandanellipticcurveE,forQ=kP,findapositiveintegerklessthanpwhenPandQareknown.ItcanbeprovedthatitiseasiertocalculateQwithkandP,butitismoredifficulttocalculatekfromQandP.Sofar,thereisnoeffectivemethodtosolvethisproblem.Thisistheprincipleoftheellipticcurveencryptionalgorithm.
Comparatio
ComparatiobetweenellipticcurvealgorithmandRSAalgorithm
EllipticcurvepublickeysystemisastrongcompetitortoreplaceRSA.ComparedwiththeRSAmethod,theellipticcurveencryptionmethodhasthefollowingadvantages:(1)Highersecurityperformance.Forexample,160-bitECChasthesamesecuritystrengthas1024-bitRSAandDSA.
(2)Theamountofcalculationissmallandtheprocessingspeedisfast.Intermsoftheprocessingspeedofprivatekeys(decryptionandsignature),ECCismuchfasterthanRSAandDSA.
(3)SmallstoragespaceoccupiedThekeysizeandsystemparametersofECCaremuchsmallerthanRSAandDSA,sothestoragespaceoccupiedismuchsmaller.
(4)ThelowbandwidthrequirementmakesECChaveawiderangeofapplicationprospects.
ThesecharacteristicsofECCmakeitsuretoreplaceRSAandbecomeageneralpublickeyencryptionalgorithm.Forexample,thecreatorsoftheSETprotocolhaveadopteditasthedefaultpublickeycryptographicalgorithminthenext-generationSETprotocol.