多种币交易和合约平台

Contents02FOREWORD04EXECUTIVESUMMARY061—PROJECTORCHIDINTRODUCTION082—MOTIVATION123—PURPOSE-BOUNDMONEY(PBM)OVERVIEW3.1PBMArchitecture3.2DigitalCurrenciesbackingPBM3.3PBMWrapper3.4PBMInfrastructure3.5PBMWallets184—PBMUSAGEPATTERNS4.1GovernmenttoPerson4.2PersontoGovernment4.3CorporationtoPerson4.4PersontoCorporation4.5PersontoPerson285—PBMFUNCTIONALOVERVIEW5.1PBMLifecycleStages5.2PBMRolesandResponsibilities5.3PBMOn-ramp&Off-ramp326—DESIGNCONSIDERATIONS6.1Interoperability6.2FungibilityofdigitalSGDacrossissuers6.3UserProtection6.4OperationalCost6.5DigitalReadiness6.6Security6.7Anti-MoneyLaunderingandTerroristFinancingRisks387—CASESTUDIES7.1CaseStudy1-GovernmentVouchers7.2CaseStudy2-CommercialVouchers7.3CaseStudy3-GovernmentPay-outs7.4CaseStudy4-LearningAccount488—SUMMARYANDNEXTSTEPS509—ACKNOWLEDGEMENTSAnnex1:CentralBankDigitalCurrencyAnnex2:TokenisedDepositsAnnex3:StablecoinsAnnex4:GlossaryofTermsForewordDigitalassetsenabledthroughtheinnovativecombinationoftokenisationanddistributedledgersoffertransformativeeconomicpotential.Tokenisationenablesanythingofvaluetoberepresentedindigitalform,storedandexchangedonaledgerthatkeepsanimmutablerecordofalltransactions.Ifdoneright,thedigitalassetecosystemcouldpotentiallyfacilitatemoreefficienttransactions,enhancefinancialinclusion,andunlockeconomicvalue.Itcouldimprovefinancialservices-acommongoalsharedbyMAS,thefinancialindustryandtheFinTechcommunity.However,likeallinnovations,digitalassetactivitiesposerisksaswellasbenefits.MAS,visionistobuildaninnovativeandresponsibledigitalassetecosysteminSingapore.Thedevelopmentstrategyandregulatoryapproachfordigitalassetsgohand-in-handtowardsachievingthis.MAS'developmentstrategymakesSingaporeoneofthemostconduciveandfacilitativejurisdictionsfordigitalassets.Atthesametime,MAS'evolvingregulatoryapproachmakesSingaporeoneofthemostcomprehensiveinmanagingtherisksofdigitalassets,andamongthestrictestinareaslikediscouragingretailinvestmentsincryptocurrencies.Innovationthroughindustrycollaborationiskeytogrowingthedigitalassetecosystem.Tosupportthedevelopmentofadigitalassetecosystem,weneedthesupportinginfrastructureformediumsofexchangetofacilitatetransactions.AnongoingfocusforMASistostrengthenourdigitalcurrencyconnectivitybydevelopingtheinfrastructureandtechnicalcompetenciesnecessarytoissueadigitalSingaporedollar(SGD).However,theonlywaytofindoutwhatworksisthroughexperimentationandexploration-“learningbydoing”.Policymakersandinstitutionscouldbenefitfrombuildingtheirownarchetypesofpossibledesignchoicesforadigitalcurrencybasedinfrastructuretopromotedebateandinnovationmovingforward.ProjectOrchidanditsexperimentsareastepforwardinadvancingthegloballearningonthepossibilityofprogrammablemoneyandpayments.RatherthanbuildingaCentralBankDigitalCurrency(CBDC)ledgerfirst,theprojecthastakenauserdrivenapproachinstead.ThefirstphaseoftheprojectaimstouncoverapotentialusecasesforaprogrammabledigitalSGDandtheinfrastructurerequired.ThesubsequentphaseofProjectOrchidwillinvestigatetheoptimalledgertechnologytoissueaCBDCaswellasitsintegrationtoexistingfinancialmarketinfrastructure.Theprojectseekstoapproachthesubjectofenablinganinnovative,interoperable,andinclusivedigitalcurrencyinfrastructureinanopen-sourcedmanner,withaviewofharnessingcollectivecontributionsofthecommunityandcontributingthelearningpointstotheglobalFinTechcommunity.SOPNENDUMOHANTYCHIEFFINTECHOFFICER,MONETARYAUTHORITYOFSINGAPORE4ExecutiveSummary--f编5、・「■_ApotentialfuturedigitalSGDwillneedtointeractwithdifferentformsofdigitalassetsandbeinteroperableacrossdifferentfinancialinfrastructures.ThisreportbeginswithanoverviewofProjectOrchid,themotivationforprogrammablemoneyandhowitsupportsadigitalassetecosystem.ThereportintroducestheconceptofPurposeBoundMoney(PBM)andthepotentialbenefitsofprogrammabledigitalcurrencythroughillustrativeusecasescontributedbyindustryparticipantsandgovernmentagencies.ThereportdiscussesthedesignconsiderationsforimplementingPBMandfeaturesfourcasestudiesbasedonongoingtrialsthathavebeeninitiatedtosupporttheexperimentsofPBMandadigitalSGD.Thetrialsstudiedthefeasibilityofpublicblockchainandtheirequivalentprivateimplementations,thoughtheirinclusionisforexperimentalpurposesonly,andshouldnotbeinferredasanendorsementontheirsuitabilityasfinancialmarketinfrastructures.ThereportconcludesbyprovidingasummaryoflessonslearntandaroadmapforfutureworkunderProjectOrchid.Centralbanks,includingMAS,wouldhavetoassesswhichcombinationoffinancialinfrastructureandtechnologybestalignswithitspolicygoals.AnimportantconsiderationstudiedinthisreportwasinteroperabilitywithotherformsofdigitalassetsthroughPBMasthecommoninterfacelayer.AlthoughMASdoesnotseeanurgentcaseforretailCBDC,itisenvisionedthatthestudyofpotentialusecasesforaprogrammabledigitalSGDandtheinfrastructurerequired,wouldenableMASandthefinancialservicesecosysteminSingaporetodevelopcapabilitiestosupportaretailCBDCshouldtheneedarises.ThesubsequentchaptersdiscusssolutionapproachesforimplementingPBMthroughacommoninterfaceandhowitmightworkwithvariousunderlyingmediumofexchanges,mainlyCBDCs,tokeniseddepositsandstablecoins.PROJECTORCHID-PROGRAMMABILITYOFDIGITALSGD71一ProjectOrchidIntroductionSince1967,Singaporehasdesignedandissueditsownnationalcurrency.ThefirstSingaporedollarnotescirculatedwereknownastheOrchidSeries,forthesprayoforchidsfeaturedinthecentreofthefrontofeachnote.MAShasactivelyexperimentedwithcentralbankdigitalcurrencies(CBDCs)anddistributedledgertechnologies(DLT)incollaborationwiththefinancialindustryandothercentralbanks,beginningwithProjectUbinin2016.MAS'experimentsto-datehaveprimarilyfocusedonwholesalecross-bordertransactionsinvolvingfinancialinstitutions,inrecognitionoftheirpotentialtoaddresslongstandingandemergingchallengesinpayments.ProjectOrchid,launchedattheSingaporeFinTechFestival(SFF)2021,marksthefirstextensionoftheseexperimentsintothedomesticretailpaymentspace(seefig1).TheoverarchingobjectiveofProjectOrchidistobuildthefoundationaltechnologyinfrastructureandtechnicalcompetenciesnecessarytoissuearetailCBDC(i.e.,adigitalversionofSingaporedollarcash),shouldSingaporedecidetodosointhefuture.•MAShasassessed1thatthereisnourgentneedforaretailCBDCinSingaporeatthispointintime.2TheusecasesforaretailCBDCareunclear,giventhatelectronicpaymentsinSingaporearepervasive,andhouseholdsandfirmsinSingaporearealreadyabletotransactdigitallyinafast,secureandseamlessmannertoday.•However,MAShasnotruledouttheintroductionofaretailCBDCatsomestageinthefuture,inlightofthedynamicnatureofthepaymentlandscape,evolvingconsumerpreferencesandlikelygrowthofthedigitalassetecosystem.34ThecaseforaretailCBDCinSingaporecouldstrengthenovertime,especiallyifinnovativeusesemergeortherearesignsthatdigitalcurrenciesnotdenominatedinSGDaregainingtractionasamediumofexchangelocally.ProjectOrchidisintendedtobeamulti-year,multi-phaseexploratoryprojectexaminingthevariousdesignandtechnicalaspectspertinenttoaretailCBDCsystemforSingapore,fromitsfunctionalitiestoitsinteractionwithexistingpaymentinfrastructures.ProjectOrchidwillbuildonthelearningsfromtheGlobalCBDCChallengeorganisedbyMASanditsglobalpartnersin2021.4Initsfirstphase,MAShaspartneredthepublicandprivatesectorstoinvestigatethepossibilitiesaroundprogrammabilityofadigitalcurrency.Forthepurposesofthispaper,tokeniseddepositsstablecoinsandCBDCsarereferredtoasdigitalcurrency.ProgrammabilityisakeyenablerofsomeofthecommonlycitedusecasesforaretailCBDC,evenasitisneitheraninherentnoruniquefeatureofaretailCBDC.AprogrammableretailCBDC,togetherwithasetofwell-designedsmartcontracts,couldfacilitatemoreefficientdisbursementofhighlytargetedorin-kindfiscalsupport(e.g.,tourismvouchers)andsupportnewbusinessandoperatingmodels(e.g.,seamlessmachine-to-machinetransactions).1

.sg/-/media/MAS/EPG/Monographs-or-Information-Paper/A-retail-CBDC---Economic-Considerations-in-the-Singapore-Context.pdf2MonetaryAuthorityofSingapore(2021),ARetailCentralBankDigitalCurrency：EconomicConsiderationsintheSingaporeContext,November.3Adigitalassetisanythingofvaluewhoseownershipisrepresentedinadigitalorcomputerizedform.Itcouldbeafinancialassetlikeabond,arealassetlikeartwork,orevenanintangibleitemlikecomputingresources.Digitalassetsaretypicallydeployedondistributedledgersthatrecordtheownershipandtransferofownershipoftheseassets.4TheGlobalCBDCChallengeisorganisedbyMAS,inpartnershipwithIMF,WorldBank,ADB,UNCDF,UNHCR,UNDPandOECD,thatseeksinnovativeretailCBDCsolutionstoenhancepaymentefficienciesandpromotefinancialinclusion.2017202020212022Cross-BorderPaymentversusPayment(PvP)ProjectOrchidProgrammabilityofDigitalSGDGlobalCBDCChallenge2021InnovativeretailCBDCSolutionsProjectUbinPhase1TokenisedSGDProjectUbinPhase2Re-imaginingRTGSProjectDunbarInternationalSettlementsusingmulti-CBDCOtherCrossBorderDigitalCurrencyConnectivityInitiativesProjectUbinPhase5EnablingBroadEcosystemCollaborationARetailCentralBankDigitalCurrencyEconomicconsiderationsintheSingaporecontextF2016L,■2023Figure1:DigitalCurrencyInitiatives8PROJECTORCHIDINTRODUCTIONPROJECTORCHID-PROGRAMMABILITYOFDIGITALSGD92——MotivationFoundationaldigitalinfrastructurewhichsupportsdigitalidentity,dataexchange,andinteroperablepayments,playanimportantroleinenablingfinancialservicestobeaccessedbyawidersetofthepopulationandsupporteconomicandsocialdevelopment.Businessesandinnovatorscouldbuilduponthesefoundationalinfrastructurestodevelopinnovativeservices,leadingtomoreefficientandaffordableserviceswithbetteruserexperiences.Oneareawheresignificantstrideshavebeenmadeinrecentyearsisthedevelopmentoftheconceptofprogrammablepaymentandmorerecentlyprogrammablemoneypopularisedwiththeblockchainandpeertopeermoneymovement.Programmablepaymentreferstotheautomaticexecutionofpaymentsonceapre-definedsetofconditionsaremet.Forexample,dailyspendinglimitsorrecurringpaymentscouldbedefined,similartodirectdebitsandstandingorders.Today,programmablepaymentsarecommonlyimplementedthroughsettingupdatabasetriggersorintheformofApplicationProgrammingInterface(API)gatewaysthatsitsbetweentheaccountingledgerandtheclientapplication.Theseprogramminginterfacesinteractwithtraditionalledgersandadjustbankaccountbalancesbasedonprogrammedlogic.Programmablemoneyreferstothepossibilityofembeddingruleswithinthemediumofexchangeitselfthatdefinesorconstraintsitsusage.Forexample,rulescouldbedefinedsuchthatthemediumofexchangecouldbedenominatedinfractionalunitsofuptoeighteenthdecimalplaces.Programmablemoneyimplementationsincludetokeniseddeposits,stablecoinsandCBDCs.Unlikeprogrammablepayment,wherebytheprogramminglogicandthevalueitselfaredecoupled,programmablemoneyisself-containedandcontainsbothprogramminglogicandservesasastoreofvalue.Whenithasbeentransferredtoanotherparty,thelogicandrulesaremovedaswell.Programmablepayment'sadvantageisitsabilitytodefineasetofprogramminglogicorconditionsthatcouldbeappliedacrossavarietyofdifferentformsofmoney.Meanwhile,programmablemoneyhastheadvantageofbeingself-containedandtransferrableonapeer-to-peerbasisbetweenparties.Athirdmodel-PurposeBoundMoney(PBM),whichisexploredintheinitialphaseofProjectOrchid,buildsupontheconceptandcapabilitiesofbothprogrammablepaymentandprogrammablemoney.PBMreferstoaprotocolthatspecifiestheconditionsuponwhichanunderlyingdigitalcurrencycanbeused.PBMsarebearerinstruments,withself-containedprogramminglogicandtransferrablebetweentwopartieswithoutintermediaries.AcrucialaspectofPBMisthattheunderlyingdigitalmediumofexchangeboundwithinitcomesembeddedwithprogrammablelogicthatmakesitpossibleforuseacrossdifferentplatformsandsystems.PBMscouldbeusedtodigitalisevouchers.Avouchercomeswithitapredefinedsetofconditionsforitsusage.Theholderofthevouchercanpresentittoparticipatingmerchantsinexchangeforgoodsorservices(aprogrammablepaymentfeature).Insomeinstances,thetermsofthevoucherschemeallowittobetransferrablebetweenpeople(aprogrammablemoneyfeature).Hence,aconsumercouldpurchaseagiftvoucherandtransferittoanotherpersonwhomaythenuseitataparticipatingmerchant.Voucherscouldalsobeissuedtosupportgovernmentdisbursementprogrammes.Forexample,CommunityDevelopmentCouncil(CDC)vouchers5,aspartoftheHouseholdSupportPackageinSingapore,aredesignedtodefraythecostoflivingandsupporthawkersandheartlandmerchantsaffectedbythepandemic.Thevouchersaredistributedtoeligiblehouseholdandprogrammedtobespentatmerchantsintheheartlands.PBMservesasdigitalbearerinstrument,andcouldineffectsupportgovernmentpayouts,Conceptually,theholderofthePBMcouldpresentthePBMandcashoutwithoutrequiringitsholderhavingtohaveabankaccount.5

.sg/news-publications/press-releases/1.5-billion-support-package-to-provide-targeted-relief-for-lower-income-households-and-vulnerable-groupsModel1ProgrammablePaymentsModel2ProgrammableMoneyModel3PurposeBoundMoneyLegendProgrammingLogicStoreofValueFigure2:PossiblemodelsofprogrammabledigitalcurrencyProliferationofSchemesTheproliferationofschemesandplatforms,increasesthecomplexityandthechallengeusersface.Voucherschemestodayoftenoperateonseparatedistributionchannelswithdistinctfeaturesfordifferentschemes.Forexample,CDCvouchersareclaimedthroughtheRedeemSG6system,anddigitalGrabvouchersareredeemedviatheGrabmobileapplication.Participatingmerchantswouldhavetotraintheirretailstafftobeabletohandleandacceptdifferentvouchers.Thiscouldbeonerous,andtherecouldbemistakesmadeduetounfamiliarity.Private,independenteffortstoconsolidatevouchersintoasingleplatformseektostreamlinetheuserexperience.Torealisethepotentialofdigitalisation,theseeffortsneedtogofurthertoensureitisopenandinteroperabilityacrossvoucherschemes.Itshouldnotlimitinteroperabilityandaccesstoonlyconsumersandmerchantswhoaresubscribedtotheirplatform.Interoperablevouchersandpaymentssystemswillallowgreaterflexibilityandprovideseamlesspaymentexperienceforbusinessesandconsumersalike.DeviationfromintendedpurposesTherisksofmisappropriationanddeviationfrompurposesspecifiedinavoucher'stermsandconditionsisapersistentconcern.Forexample,withdirectpay-outstoaperson'sbankaccountortheuseofcheques,itisnotpossibleforthesendertodirectthattherecipientsspenditatapprovedmerchantsandnotonvices.AdministrativeoverheadCampaignorganisersneedtotypicallyfigureoutahostofadministrativeissues.Theywouldneedtofigureoutoperations-e.g.distributionofvouchersacrossdifferentchannels,trackingvoucherredemptions,troubleshootingdisputes.Currently,eventhoughmerchantsmayhavebeenonboardedtoaparticularsystem(e.g.onboardedtotheRedeemSGsystem),theywouldstillneedtosignacontractwithcampaignorganiserstoagreetoacceptvouchersforeachnewcampaignitsupports.Inaddition,underexistingvoucherschemes,participatingmerchantsdonotreceivefundsimmediately.Aftersubmittingaclaimtothevoucherissuerandwaitingfordaysorweeks,thesumisvalidatedandtheamountiscreditedtothemerchants'bankaccounts.PBMdefinesacommoninterfacelayerthatcanbeusedbetweendifferentpaymentserviceproviders,merchantsandendconsumerstointeractwithoneanotherwithoutexpensiveorproprietary3rdpartyequipmentorinstitutionstoreceivepayments,nordotheyhavetobuildbilateralnetworksuniqueonlytothepartiesinvolvedinthetransaction.ProviderscouldbuilduponthePBMstandardtofosterinnovationwhilestillensuringcompatibilitywithvariousdevicesandacollaborativefinancialecosystem.TheintroductionofPBMcouldfacilitategrantdisbursementsandmitigatefraudandmisusebyembeddingintrinsicconditionswhichgoverntheuseoftheunderlyingdigitalcurrencies.OtherexamplesoftheusagepatternsofPBMarediscussedinSection4ofthisreport.6

RedeemSGisavouchersystemthathelpsSingaporeGovernmentagencieseasilycreate,issueandtracktheredemptionofvouchers.ItalsoenablesmerchantstoeasilyacceptGovernmentissuedvouchers.10MOTIVATIONPROJECTORCHID-PROGRAMMABILITYOFDIGITALSGD5一Purpose-BoundMoneyOverviewTheconceptscoveredinthissectionserveasthebasisfordiscussingthefunctionalitiesofPBM,theirbenefitsandrisksandinvestigatehowtheycouldbesupportedbydifferentunderlyingdigitalcurrenciesacrossdifferentrealworldusecases.3.1PBMArchitectureCommercialVoucherERC-1155formultipleissuers,multipleconsumersGovernmentDisbursementERC-20forsingleissuermultipleconsumersOtherUseCasesReceiveWalletsConsumerConsumerConsumerMerchantsMerchantsMerchantsProgrammedBusinessLogicIssuerslockincollateraltocreatePBMFiatAccountsPBMWrapperCollateralLegend■Self-custody■Third-PartyCustody■PBMTokens■FungibleDigitaltokens口OrderoftheflowFigure3:PBMArchitectureDiagram15APBMbasedarchitecturehasfourdistinctcomponents.1.DigitalcurrencybackingPBMThedigitalcurrencybackingaPBMservesascollateralforthePBM.WhentheconditionsofaPBMarefulfilled,theunderlyingdigitalcurrencyisreleased,andownershipistransferredtothetargetrecipient.Tobeutilisedasabackingdigitalcurrency,adigitalassetneedstobeagoodstoreofvalue,unitofaccountandamediumofexchange.BackingdigitalcurrenciescouldcomeintheformofCBDCs,tokeniseddepositsorstablecoinsthatareproperlyregulatedinamannerthatprovidesconfidenceinthestabilityoftheirvalue(hereinknownas“securelybackedstablecoins”).BackingdigitalcurrenciescouldbeimplementedasanERC-20fungibletokensmartcontract.2.PBMWrapperThePBMWrapperimplementedintheformofsmartcontractcodespecifiestheconditionsuponwhichanunderlyingdigitalcurrencycanbeused.ThePBMWrappercouldbeprogrammedwherebythePBMcanonlybeutilisedforitsintendedpurposes,suchasvaliditywithinacertainperiod,atspecificretailers,andinpredetermineddenominations.OncetheconditionsspecifiedinthePBMWrapperaremet,theunderlyingbackingdigitalcurrencywillbereleased,andtransferredtotherecipient.Forexample,thepurposelayercouldbeimplementedasanERC1155Semi-FungibleTokensmartcontract.73.PBMInfrastructureTheownershipofadigitalcurrencyandthesmartcontractsgoverningitsusageareexecuteduponaledger-basedinfrastructure.ThePBMinfrastructureestablishesthefoundationfortheimplementationofProgrammableMoneyandenablesnewpossibilitiesforinteractionsamongconsumers,merchants,financialinstitutions,andgovernmentagencies.Theledger-basedinfrastructurecouldbeDLTornon-DLTbased.4.PBMWalletPBMwalletsareusedbyuserstosendandreceivePBMsandtherespectivebackingdigitalcurrencies.Theyrefertocryptographicwalletswhicharesoftwareprogrammesthatholdusers'privatekeysthatgrantsthemaccesstoPBMs.3.2

DigitalCurrenciesbackingPBMInadditiontoaretailCBDC,PBMtechnologyisalsodesignedtoworkwithotherpromisingformsofdigitalcurrenciesthatcouldcirculateasprogrammable“money”inthefuture,namelytokeniseddepositsand“securelybacked”stablecoins.Anyformofelectronicordigitalmoneycanbeconsideredintwoparts:themonetaryinstrumentitselfandthesupportinginfrastructurethatallowsbalancestobemanagedandtransferred.WhilethestartingpointisaretailCBDC,thePBMtechnologyhasbeendesignedtobe简CBDCBTokenisedDepositsStablecoinPurposeBoundMoney(PBM)Merchant4FinancialInstitutionFigure4:IllustrationofDigitalcurrenciesbackingPBMRetailUser7EthereumRequestforComments(ERC)arespecificationsforEthereumapplications,suchastokenstandards,nameregistries,libraryformats,andpackageformats.ERC-1155isatokenstandardthatenablestheefficienttransferoffungibleandnon-fungibletokensinasingletransaction.14PURPOSE-BOUNDMONEYOVERVIEWPROJECTORCHID-PROGRAMMABILITYOFDIGITALSGDTheinclusionofemergingformsofdigitalcurrenciesinthedesignofthePBMissolelyforexperimentalandexploratorypurposesbasedontechnicalgroundsandinrecognitionofthepotentialtheymaypresent.agnostictothetypeofliabilityunderlyingit.Threeconsiderationsunderpinthisdesignchoice:First,MASexpectsthat,asamonetaryinstrument,anyfutureretailCBDCwillonlyformasmallpartofourmoneysupply,playingausefulbutultimatelyconstrainedroleintheeconomyjustlikephysicalcash.Today,banknotesandcoinsissuedbyMASonlyaccountforaround8%ofourentiremoneysupply,withprivatelyissuedmoneyintheformofbankdepositsmakinguptheremaining92%.Second,theretailCBDCsystemwillformpartofSingapore'snationalfoundationaldigitalinfrastructure,whichbringstogetherpayments,digitalidentityanddataexchangeandauthorisationandconsentmechanismstoprotecttheprivacyandwelfareofindividualsmoreholistically.Asapublicpaymentrail,itisexpectedtoplayanimportantroleinensuringthattheminimumstandardsrequiredofpayments(e.g.,intermsofsafety,speed,convenienceandfees)arepresent.MASthusenvisagestheretailCBDCsystemtobeacommonandopenback-endplatformthatisfullyinteroperablewithotherexistingpaymentsystems.Lastly,andtoasmallerextent,MASismindfulthatthecaseforaretailCBDCinSingaporeremainsopenatthispoint.Therapidpaceatwhichinnovationsareunfoldinggloballyalsomeansthatitisstilltooearlyatthispointintimetotellhowthefutureofmoneyandpaymentswillultimatelypanout.Againsttheseuncertainties,itisMAS'hopethatintheprocessofbuildingupthenecessarytechnicalcapabilitiestoissuearetailCBDC,MASisabletocontributetothecommonpoolofknowledgethatwillbeusedtoadvancethestateofpayments,regardlessofoureventualdecision.ThesereasonssuggestthatforthePBMtechnologytobe"future-ready”andinlinewithMAS'vision,itshouldideallybecompatiblewithotheremergingformsofdigitalcurrenciesthatcouldpotentiallycirculateas“money”inthefuture(i.e.,amediumofexchangewidelyacceptedforpaymentofgoodsandservicesintherealeconomy,astablestoreofvalue,andaunitofaccount).Basedoncurrentdevelopments,possiblecandidates(withvaryingdegreesoflikelihood)aresyntheticCBDCs,tokeniseddepositsand"securelybacked”stablecoins.Cryptocurrencies(e.g.,bitcoin)andotherformsofstablecoins(e.g.,commodity-backedorunbackedandwhichadoptanalgorithmicmechanismtomaintainstability)-basedontheircharacteristicstoday-areunlikelytohavepotentialtobecirculatedas“money”.Account-basedmodelstypicallysupportsprogrammablepaymentswhiletoken-basedmodelssuchasCBDCsandtokeniseddepositsareProgrammableMoneywithrulesembeddedwithinthemoneyitself.PBMwrapstheProgrammableMoneywithconditionsthatwillexpireoncetheyhavebeenmet.UndertheinitialphaseofProjectOrchid,participatingfinancialinstitutionsandgovernmentagenciestestedPBMwithtokeniseddepositoranexistingSGD-denominatedstablecoin.FuturephasesoftheprojectmayincludetestingwithanMASissuedCBDC.TheinclusionofemergingformsofdigitalcurrenciesinthedesignofthePBMissolelyforexperimentalandexploratorypurposesbasedontechnicalgroundsandinrecognitionofthepotentialtheymaypresent.Foreditorialpurposes,CBDCs,tokeniseddepositsandsecurelybackedstablecoinsissuedbyregulatedfinancialinstitutions,whicharedenominatedinSGD,arecollectivelyreferredtoas"DigitalSGD”inthisreport.3.3

PBMWrapperPBMcanbecreatedfromthedistincttypesofdigitalcurrencies,highlightedintheearliersection,throughwrappingthesedigital15currenciesinthePBMsmartcontract.AfterthePBMhasbeencreated,itisdistributedtotheconsumers.ConsumerswillonlyinteractwithPBMinitswrappedform,andtheydonothavetomanageorhandletheunderlyingdigitalcurrency.Consequently,thereisnoneedforvoucherissuerstoissuetheirownpaymentinstrument.Essentially,PBMCreatorsarenotissuingnewpaymentinstrumentsasPBMsattachconditionstoexistingpaymentinstruments.AnanalysisoftheusecasespresentedbythePBMworkinggroupsuggeststhataPBMundergoessimilarlifecyclestages,regardlessofitsunderlyingtechnicalimplementation.Consequently,thereismeritindevelopinganopen,standards-basedinterfacespecificationthatwillserveasacommonframeworkforfuturePBMdevelopmentwork.Theprovisionoftheinterfacespecificationthroughanopen-sourcesoftwareprojectwillfurtherencourageadoptionandenablegreaterinteroperability