Imbali Yobugcisa yeBitcoin

I-Bitcoin ayizange ivele ngaphandle kwemvelaphi, kodwa yakhiwe kumsebenzi wabaninzi kwiishumi leminyaka ezidlulileyo. Eli candelo liza kuphonononga iziseko ze-intanethi apho i-Bitcoin yakhiwe khona, kunye nophando nophuhliso oluqatshelwe kwiphepha elimhlophe.

Ngeminyaka yoo-70, iqela labantu laqwalasela indlela uRhulumente wase-US awayezama ngayo ukuthintela ukufikelela kwi-cryptography, baza baqalisa ukuqinisekisa ukuba le teknoloji iya kufumaneka kubo bonke abantu ukuze bakwazi ukukhusela ubumfihlo babo kwi-intanethi. Abanye babaseki bokuqala babegxile nakwizibonelelo ezinokubakho zenkqubo yemali yedijithali 'eqinileyo' enokusetyenziswa ukugcina nokutshintshiselana ngexabiso kwi-intanethi esakhulayo. U-Friedrich Hayek – ongomnye wabaqulunqi abaphambili kwezoqoqosho zase-Austria – wacinga ukuba imali efanelekileyo esekwe kukhuphiswano lwemarike yasimahla inganjani, kudala phambi kwexesha le-intanethi, kodwa wagqiba kwelokuba ayinakwenzeka ngokwezobuchwephesha nezopolitiko. Ukongeza kubumfihlo bedijithali, eli qela, elathi lagqibela laba yiCypherpunks, lazama ukuphumeza umbono kaHayek wemali yedijithali, kodwa ezi nzame zaphumelela kuphela emva kokuba uSatoshi epapashe izimvo zakhe kuluhlu lwe-imeyile.

• Umgaqo-nkqubo we-TCP/IP (1976)
• Imigaqo-nkqubo yeNkqubo yeSitshixo soLuntu - Ralph Merkle (1980)
• Digicash - David Chaum (1989)
• Ukubekwa kweempawu zexesha kwidijithali (ii-90's)
• Hashcash - Adam Back (1997)
• BitTorrent - Bram Cohen (2001)
• Reusable POW - Hal Finney (2004)
• Bitcoin Whitepaper - Satoshi Nakamoto (2008) 

Impembelelo ephambili kuphuhliso lweBitcoin yayikukuphuma kwentshukumo yeCypherpunk kwiminyaka yoo-90. Baphuhlisa itekhnoloji ezininzi ze-cryptography kubandakanya i-public-key cryptography ukuze abasebenzisi bakwazi ukunxibelelana kwaye babelane ngolwazi ngokhuseleko nangasese. Uninzi lophuhliso oluchazwe apha kunye nabantu abathathe inxaxheba babengamalungu aleli qela. 

Imfuno yemali yedijithali nayo yaqatshelwa kwaye kwenziwa iinzame ezininzi zokuyenza, kodwa zazinezithintelo ezazibangela ukuba zingaphumeleli. Ubukrelekrele bukaSatoshi Nakamoto yayikukudibanisa ezi zakhono, kwaye kunye nezinye izinto ezintsha zakhe, wakha kuzo ukwenza i-protocol yeBitcoin esetyenziswa namhlanje. Kwicandelo elilandelayo siza kuphonononga ezinye zale nkqubela phambili kwaye sichaze indlela ezanceda ngayo kuyilo lweBitcoin. Siza kuxoxa kwakhona ngezinto ezazilahlekile ezazisafuneka ukuba zisombululwe nguSatoshi.

Uninzi lwethu luqhelene neendlela ze-TCP/IP ezisetyenziswa namhlanje njengesiseko se-intanethi. Imvelaphi yazo ibuyela emva kwiminyaka yoo-1970 xa izazinzulu zaziphanda ezinye iindlela zokuyila i-Arpanet – inethiwekhi eyayisungulwe ngaphambili nguMphathiswa Wezokhuselo waseMelika ukuze kwabelwane ngezixhobo phakathi kweekhompyutha ezikude. I-TCP/IP yaba ngumgangatho wenkqubo ye-Arpanet ngo-1983, nto leyo eyabangela ukuba ibe yindlela ephambili yokunxibelelana ngothungelwano ekupheleni kweminyaka yoo-1990 kwaye yaba siseko se-intanethi apho iBitcoin isebenza khona namhlanje.

Ngexesha elifanayo xa kwakuphuhliswa imodeli ye-TCP/IP, kwakuphuhliswa nesakhelo esifanayo kodwa esibanzi ngakumbi yi-International Standards Organisation (ISO) kunye neshishini le-Telecoms (CCITT). Inkqubo yokuphuhlisa iindlela ezintsha okanye ukucetyiswa kweetshintsho yayihamba kancinci kwaye inzima xa ithelekiswa nendlela engaphezulu yokuzimela eyasetyenziswa kuphuhliso lwe-TCP/IP, nto leyo eyabangela ukuba le ndlela ibe ngumphambili namhlanje.

Isicelo Senguqu

Nawuphi na uphuhliso olucetywayo kwiindlela ezikhoyo okanye izimvo ezintsha zingacetyiswa kwimodeli ye-TCP/IP ngokusebenzisa Isicelo Senguqu inkqubo. Ezi zidlula kwinkqubo yokuvunywa, ephethwe yi-Internet Engineering Task Force (IETF), kwaye ziba yisoftware evulekileyo xa zivunyiwe ukuze nabani na akwazi ukuzisebenzisa nokuzamkela. Eminye imizekelo ebalulekileyo:

• 1969 RFC 1 Ixhase indlela iipakethi eziza kuthunyelwa ngayo kwi-Arpanet
• 1981 RFC791 ichaze indlela ye-Internet protocol V4 – esisetyenziswa kakhulu nanamhlanje
• 1982 RFC 821 Inkqubo elula yokuthumela i-imeyile
• 1987 Inkqubo yeDomain Name System – indlela amagama e-domain aguqulelwa ngayo kwiidilesi ze-IP
• 1999 RDC 2616 Inkqubo yeHypertext Transfer – ebalulekileyo ekukhangeleni kwiwebhu

I-Bitcoin Improvement Proposal (BIP) ilandela indlela efanayo ne-RFC, kodwa igxile kuphela ekuphuculeni iBitcoin ngokwayo endaweni yokuphuhlisa iindlela ezintsha okanye ezizezinye. IBitcoin ikwathatha kule modeli enamanqanaba, kwaye uza kubona ezinye iindlela zichazwa njengomphakamo wesibini okanye wesithathu.

Njengokuba amanqanaba asezantsi emodeli ye-TCP/IP engatshintshanga kakhulu kule minyaka idlulileyo, ngelixa izinto ezintsha zenzeka kumphakamo ophezulu, umphakamo osezantsi weBitcoin kulindeleke ukuba utshintshe kancinci ngeli xesha, nezisombululo zokwandisa ezifana ne-Lightning ne-Liquid zenzeka ngaphezulu.

Umzekelo olungileyo wokuba indlela esisiseko yokunxibelelana iba nzima ukuyitshintsha ngokuhamba kwexesha yi-IPv6. Ukuphela okulindelekileyo kwendawo yeedilesi kwi-IPv4 kwadala imfuno yendlela entsha. Umgaqo-siseko wokuqala wadalwa ngo-1998, kodwa awuvunywanga njengomgangatho we-intanethi de kwango-2017. Nangona isombulule iingxaki ezininzi ze-IPv4 kwaye iyakwazi ukumelana nekamva, isasetyenziswa kancinci kakhulu kwishishini namhlanje. Ngeli xesha, iindlela ezininzi ezintsha zichaziwe kumphakamo ophezulu ukuvumela imultimedia, i-imeyile njl.

Izinto ezisisiseko ezisetyenziswa yiBitcoin

Olu lwahlulo lweengxaki zonxibelelwano luvumela iindlela zokunxibelelana ukuba ziphuhliswe ngokuzimeleyo kumphakamo ongaphezulu okanye ongezantsi kwayo. Endaweni yokuphinda kusonjululwe iingxaki kumphakamo ngamnye, inethiwekhi yeBitcoin inokuxhomekeka kumandla esisiseko anikezelwa kumphakamo womzimba kunye nekhonkco ledatha.

I-Bitcoin yindlela engathathi hlangothi yokudlulisa ixabiso njengoko i-HTTPS iyindlela yokudlulisa ulwazi

• HTTPS: IiWebhusayithi Ezikhuselekileyo
• SMTP: Thumela ii-imeyile
• FTP: Guqulela iifayile
• DNS: Lawula amagama edomain
• BTC: Gcina kwaye guqulela ixabiso

I-Bitcoin ivumela ukuba ixabiso lithuthwe ngokuthembekileyo kwaye ngaphandle kokufuna umntu wesithathu phakathi kwabantu okanye izixhobo kwi-Intanethi. Oku kulindeleke ukuba kuvule ixabiso elikhulu.

Namhlanje i-Intanethi, kunye neenkqubo ezininzi zekhompyutha zale mihla, zixhomekeke kwi-cryptography, indlela yokufihla ulwazi ukuze kuphela umamkeli wolwazi akwazi ukuluvula. Iziseko ze-cryptography ezisetyenziswa ukukhusela iBitcoin zingalandelwa emva kwiminyaka yee-70.

Ingxaki yokuqala ekufuneka isonjululwe yile – indlela yokuthumela imfihlo esabelwana ngayo phezu kwendlela engakhuselekanga.

Oku kwaqala kwaphandwa nguWhitfield Diffie noMartin Hellman.

Ingxaki: amaqela amabini – ahlala ebizwa ngokuba ngu-Alice no-Bob – afuna ukwabelana ngolwazi oluyimfihlo kwinethiwekhi apho abanye banokumamela. Ukuze bakwazi oku, badala inkqubo yokutshintshiselana ngesitshixo kaDiffie-Hellman.

Le mfihlo esabelwana ngayo ingasetyenziswa njengembewu yokudala izitshixo ezininzi ezifanayo zokufihla nokuvula imiyalezo abayithumelanayo ngaphandle kokwabelana ngesitshixo ngokwalo esidlangalaleni.

Njengoko isitshixo sabucala singaze sabelwane ngaso, kwaye izitshixo ezahlukeneyo zisetyenziswa kwicala ngalinye ukufihla nokuvula, oku kubizwa ngokuba yindlela yokufihla engalinganiyo (asymmetric encryption algorithm).

Iimeko zokusetyenziswa:

• UAlice usayina umyalezo ngesitshixo sikaBob soluntu – ongulowo kuphela onokuwuvula esebenzisa isitshixo sakhe sabucala
• UAlice usayina umyalezo ngesitshixo sakhe sabucala – ngokuwuvula ngesitshixo sakhe soluntu nabani na angaqinisekisa ukuba umyalezo uthunyelwe nguAlice, ngaphandle kokwazi isitshixo sakhe sabucala
• Xa ezi ndlela zimbini zidibanisiwe kunye nemigangatho emibini yokufihla, umyalezo unokuthunyelwa ufihlakele ukuze kuphela uBob akwazi ukuwuvula, aze akwazi nokuqinisekisa ukuba umthumeli ebenguAlice ngenene

Nangona engakhange anikwe imbeko ephepheni, uRalph Merkle waba negalelo elikhulu ekusombululeni le ngxaki eyayijongwa njengengenakwenzeka – indlela yokuseka okanye ukuphinda kusekwe unxibelelwano lwabucala kwinethiwekhi evulekileyo nenokuthi ibe nobungozi.

Le ndlela yodwa isengaphantsi komngcipheko wokuhlaselwa ngamandla (brute force attack), apho umhlaseli angathatha amanani abelwana ngawo aze ekugqibeleni enze isitshixo esabelwana ngaso xa enexesha nezixhobo ezaneleyo, ngoko ke ayisosisombululo sipheleleyo yodwa.

Iinkqubo zeNkqubo zeSitshixo soLuntu (Public Key Cryptosystems)

Ukongeza ekunikezeleni kwinkqubo yesitshixo soluntu kaDiffie-Hellman echazwe ngasentla, Ralph Merkle waqhubeka nokunika igalelo kule ndawo iminyaka emininzi, kwaye waba negalelo elikhulu kuphuhliso lwezinto eziphambili ezisetyenziswa yiBitcoin.

Umsebenzi wokuhashisha kwi-cryptography yindlela ye-mathematics ethatha imiyalelo yobungakanani obuphina kwaye iqhube iibalansi ezinzima ukuze ibuyise ixabiso le-hash kwi-bits, elihlala limelwe sisiphumo esingaguqukiyo sobude obuthile esisebenzisa ifomathi ye-hexadecimal.

• Imiyalelo ingaba nobungakanani obuphina
• Isiphumo sihlala sinesilinganiso esingaguqukiyo kwaye siyaphindaphindeka (umyalelo ofanayo uvelisa i-hash efanayo rhoqo)
• Kulula ukuqinisekisa kodwa kunzima kakhulu ukubuyisela umva inkqubo ukuze kufumaneke umyalelo wangaphakathi
• Utshintsho oluncinane kwidatha lutshintsha ngokupheleleyo iziphumo

Ukusebenza kwe-hash yinxalenye ebalulekileyo kwinkqubo yeBitcoin. I-SHA-256, esetyenziswa kwiBitcoin, yadalwa yi-NSA kwaye ngumzekelo womsebenzi wokuhashisha kwi-cryptography.

• Ibhloko nganye kwikhonkco iyahashishwa ukuze idatha ingatshintshwa – oku kuqinisekisa ukuthembeka kwe-ledger esasazekileyo
• I-hash evelisiweyo kufuneka ihlangabezane nemigangatho ye-‘Proof of work’ ukuze ithathwe njengebhloko evumelekileyo
• Imithi kaMerkle – ngokusebenzisa amasebe kunye ne-hash ye-hash, imithi ye-hash ingavumela ukuqinisekiswa kweedatha ezinkulu ngokugcina indawo encinci
• Iisayini kunye nezitshixo ezisekwe kwi-hash zingasetyenziswa kwi-wallets, iidilesi kunye nemvume yokwenza iintengiselwano

Ukuqinisekiswa okusasazekileyo kweemeko zeblockchain kunye nemodeli ye-ledger enokongezwa kuphela engalungiswayo kwenziwa yindlela yokuhashisha engabuyiswayo. Imisebenzi ye-hash ibonelela ngendlela ethembekileyo, ephindaphindekayo yokuqinisekisa iziganeko kwiiledger zoluntu ezifana neBitcoin xa kungekho mzekelo wokuthembana ophakathi.

Ezi zakhono zintsha kwindawo ye-cryptography zazilindeleke ngabadali bazo ukuba zize nezinto ezintsha kule ndawo.

I-cryptography ye-elliptic curve

Enye yezi zinto zintsha kamva yafika ngendlela ye-elliptic curve cryptography.

I-elliptic curve cryptography yaziswa ngo-1985 ngososayensi ababini, uN. Koblitz noV. Miller. Bacebisa umbono wokusebenzisa amanqaku achazwe yi-elliptic curves endaweni yamacandelo aphambili anemida ukuze ingxaki ye-Discrete Logarithm isebenze, njengoko kusetyenziswa rhoqo kwinkqubo yesitshixo kaDiffie-Hellman. Iinkcukacha zokusebenza kwayo ziphaya kolu candelo, kodwa ngokubanzi, i-elliptic curve yiseti yamanqaku ahlangabezana nelinge lemathematics elithile.

Ilinge le-elliptic curve libonakala ngolu hlobo:

Oku kuneempawu eziluncedo:

• Ukulingana ngokuthe nkqo. Naliphi na inqaku kwicurve linokuboniswa kwakhona ngaphezulu kwe-x axis kwaye lihlale likwicurve efanayo.
• naluphi na ulayini ongathe nkqo uya kudibana ne-curve kwiindawo ezingaphezulu kwezintathu kuphela.
• Ubungakanani bezitshixo ezincinci bubalulekile ekugcineni nasekuthumeleni izitshixo zoluntu kwi-blockchain ngendlela efanelekileyo.

Ezi mpawu zingasetyenziswa ukudala izibini zezitshixo ngendlela efanayo ne-algorithm kaDiffie-Hellman. IBitcoin isebenzisa i-ECDSA, ethetha i-Elliptic Curve Digital Signature Algorithm. Yinkqubo esebenzisa i-elliptic curve kunye nentsimi enomda 'finite field' ukuze 'isayine' idatha ngendlela yokuba abantu besithathu bakwazi ukuqinisekisa ubuqiniso besayini ngelixa umsayini egcina amandla okukwazi ukwenza isayini kuphela. KwiBitcoin, idatha esayinwayo yintengiselwano edlulisa ubunini.

Icandelo 'elinemida' lifana nendlela ye-'mod' kwiDiffie-Hellman, apho isiphumo selinge sahlulwe kwaye intsalela isetyenziswa ukuqinisekisa ukuba ihlala kuluhlu lweenani.

Omnye wabathathi-nxaxheba bokuqala 'kwigagasi elitsha lomdla' kwi-cryptography yayinguDavid Chaum. Wachitha iminyaka yakhe yokuqala efunda ukophula iinkqubo zekhompyutha kwaye impumelelo yakhe yakhokelela ekungathembini iinkqubo ezithiwa 'zikhohlo'. Waphinda waqaphela ingxaki engazange ithathelwe ingqalelo ukuza kuthi ga ngoku: "indlela yokugcina imfihlo yolwazi lokuba ngubani othetha nobani kwaye nini".

Waqamba inkqubo yemeyile engaziwayo esebenzisa i-public key cryptography eyayixuba imiyalezo ukuze kugcinwe imvelaphi kunye nendawo ekuyiwa kuyo ingaziwa. Le nto yaba sisisiseko senethiwekhi ye-TOR.

Chaum wabona iintlawulo zedijithali ngendlela efanayo – waqonda ukuba 'iintengiselwano zemali ezilandelwayo ezenziwa ngumntu ngamnye zinokutyhila okuninzi malunga nendawo ahlala kuyo, abantu ahlangana nabo kunye nendlela aphila ngayo'. Ngo-1980 wafumana ipatent yenkqubo yemali yedijithali ekhuselekileyo nge-cryptography eyaba sisisiseko se-cryptocurrency. Waqalisa nokuphanda umbono wokusebenzisa i-cryptography ukwenza uqoqosho oluzimeleyo ngokupheleleyo olusekwe ekuzimeleleni kwemiyalezo kunye neentlawulo.

Oorhulumente banobuchule bokunqumla iintloko zeenethiwekhi ezilawulwa embindini ezifana neNapster, kodwa iinethiwekhi ezicocekileyo ze-P2P ezifana neGnutella ne-TOR zibonakala zikwazi ukuzimela.Satoshi Nakamoto

Iinkqubo ezizimeleyo ngaphandle komphathi ophakathi – peer-to-peer – zinikezela ngeengenelo ezininzi:

• Zinokukhula ngokukhawuleza kuba nabani na angakhulisa inkqubo ngokusebenzisa i-node entsha ngaphandle kokubhalisa okanye ukufumana imvume
• Zonke ii-node ziyafana ngoko ukusilela kunokujikelezelwa
• Akukho gunya eliphakathi elinokubanjwa okanye lonakalise inkqubo
• Kunzima ngakumbi ukuzibamba, ukuzilawula, ukuzirhweba okanye ukuzijonga ngaphandle kwamacandelo alawulwa embindini

Kwiminyaka elishumi kamva waseka inkampani yakhe, iDigicash ukwenza 'ecash' inkqubo yokuqala yemali yedijithali emhlabeni. Amagama amaninzi adumileyo ajoyina iDigicash okwethutyana, eyabona impumelelo ethile kodwa ekugqibeleni yasilela yaza yachitha imali.

Uphuhliso olungakumbi kwimali yedijithali

Kwiposti ye-forum ngoJulayi 2010, uSatoshi Nakamoto wathi: “Bitcoin sisicelo sikaWei Dai se-b-money kwiCypherpunks ngo-1998 kunye nesindululo sikaNick Szabo se-Bit Gold.”

Nangona ezi ngcinga zimbini zingazange zidlule kwisigaba sesindululo, ezinye zezimvo ezikuzo zacebisa ngokucacileyo uphuhliso lweBitcoin:

• Ukusebenzisa 'Proof of work' ukunikezela ngexabiso lemali kumsebenzi wokubala
• Ingcinga yokuba iindleko zokubala zitshintsha ngokuhamba kwexesha kwaye kufuneka zithathelwe ingqalelo

Kodwa kuqala siza kujonga iHashcash.

UHashcash wadalwa nguAdam Back, omnye wabantu bokuqala abenza izinto ezintsha kweli candelo. UAdam wayenomdla omkhulu kwiimarike ezikhululekileyo kunye nobumfihlo kwi-intanethi, kwaye wadibana noluhlu lwe-imeyile lweCypherpunks apho wajoyina waba ngumthathi-nxaxheba osebenzayo.

Wayenomdla kakhulu kwimali yedijithali, kwaye wenza iingcebiso ezithile zokuba iqela linokusebenza ngokusondeleyo kwiDigiCash kunye noChaum, kodwa ezi azizange ziphumelele. Emva koko wajolisa ingqalelo yakhe kwenye ingxaki eyayisanda kuvela – i-imeyile engafunekiyo (spam). Yena kunye nabanye beCypherpunks babefuna ukufumana isisombululo kule ngxaki ye-spam, apho kwakulula kakhulu kubathumeli be-spam ukwenza nokuthumela amawaka e-imeyile ezalisayo iinethiwekhi. Isisombululo sakhe esiyingqayizivele sasisebenzisa i-hashing – amandla e-cryptography okuguqula naluphi na ulwazi lube ngumtya owodwa nowahlukileyo wobude obuthile, ukwenza into efana 'nesitampu' sedijithali ekufuneka yongezwe kwi-imeyile ukuze ithathwe njengeyiyo kwaye ithunyelwe kwinethiwekhi. Iindleko ezincinci kwi-imeyile yokwenene, kodwa ezinzima kumthumeli we-spam.

Uphuhliso oluphambili olwenziwa yiHashcash yayikukudibanisa izixhobo zangempela – amandla okusebenza kwekhompyutha – kwinethiwekhi yedijithali. Ngelixa izixhobo zedijithali kude kube ngelo xesha zazisenokuphindaphindwa ngaphandle komda, inani le 'hashcash' elenziwayo lalilinganiselwe ngokuba abantu bazimisele ukusebenzisa amandla amangakanani kuyo.

Nangona isisombululo sasihlangabezana nezinye zeemfuno uAdam wayekholelwa ukuba ziyimfuneko kwinkqubo yemali yedijithali; yayiyimfihlo, yomelele kwaye ingaxhomekekanga kuthembeko, kodwa i-hashcash nganye yayingasetyenziswa kwakhona kwaye yayinganyaniyo ngokwenene. Wacebisa ezinye iindlela zokuba ezi ngxaki zingasombululwa kusetyenziswa amaqela angaphandle.

BitGold

UNick Szabo wakha phezu kwengcamango yeHashcash kunye nobungqina bomsebenzi (proof of work) ukuze acebise esinye isisombululo, awayesichaza kuluhlu lwe-imeyile kunyaka emva kokupapashwa kweHashcash, ngo-1998.

Nangona esondela kwisombululo, esi siphakamiso sasisenemingeni emininzi.

• Ngubani oza kulawula iRegistry yobunini be-hash kwaye bangathembeka njani?.
• Ukusebenzisa i-hashing kuya kuthi kungabizi mali kakhulu ngokuhamba kwexesha, leyo yayingumceli-mngeni nakwiHashCash.

Njengoko ii-hash ezinxulumeneyo ziya kufakwa i-time-stamp, wacebisa uhlobo oluthile lokulandelela imbali yobunzima bokwenza i-hashing ngelo xesha; i-hash yangaphambili yayiza kufuna iindleko zokusebenza eziphezulu kunele yakamva njengoko iindleko ziye zehla. Ngelishwa, oku kwakuthetha ukuba ii-hash bezingayi kuba 'fungible' oko kukuthi, zexabiso elifanayo, nto leyo ithathwa njengento ephambili kwimali yedijithali. Ukuze ancede ukusombulula oku, uNick wacebisa uhlobo oluthile 'lwebhanki ezikhululekileyo' ezisebenza phezu kweBitGold ezaziza kuhlanganisa amaqela ahlukeneyo ee-hash ezaziza kuxatyiswa ngokufanayo.

B-Money

Kungekudala emva kwesiphakamiso seBit Gold, uWei Dai wacebisa isisombululo esifana neso. Wayesele ephuhlise ezinye izixhobo ezininzi zeCypherpunks, kwaye wayenezimvo zakhe ngemali yedijithali.

Isiphakamiso sakhe sasifana neBit Gold kuba sasisebenzisa utyikityo lwedijithali ukugqithisela imali, kwaye iirekhodi zotshintshiselwano zaziza kugcinwa kwiledger, equlathe izitshixo zoluntu kunye nenani leyunithi zemali ezinxulunyaniswa nomntu ngamnye. NjengeBit-Gold, amaqela athembekileyo athathwa njengezithuba zokhuseleko, kwaye inkolelo yayikukuba inkqubo yemali yombane akufuneki ixhomekeke kwiqela elinye ukulandelela ibhalansi, iintengiselwano okanye ukuthintela ukusetyenziswa kabini kwemali.

UWei-Dai wacebisa izisombululo ezininzi kwezi ngxaki, enye yazo yayikukuba endaweni yokuba kube nombutho ophakathi ogcina i-ledger, ZONKE i-node zaziza kugcina ikopi yayo. Ukuba bonke abasebenzisi bajonga i-ledger yabo kunye nokusebenziseka kwentengiselwano nganye, logama zonke ii-node zihlaziywa ngexesha, ii-ledger ziza kuhlala zidityanisiwe kwinethiwekhi. Le nkqubo isasazeke kakhulu yayingayi kuba lula ukonakaliswa.

UWei Dai waqonda ukuba oku akusombululi ingxaki ye-Byzantine generals (1), njengoko ii-node zinokuphulukana lula nokudityaniswa okanye zixoke nje. Wacebisa ezinye iindlela ezifana nokuba kube neseti yeeseva 'ezithembekileyo' ezigcina i-ledger, kunye nokudala imivuzo yezemali ukugcina ezi seva zithembekile.

Kwipolisi yemali, wacebisa ukuxhasa amandla okuthenga kweB-Money kwindlela ethile ye-consumer price index yangaphandle. Wayefuna ukuba inani elifanayo leB-Money likwazi ukuthenga isabelo esilinganayo kwi-index ngokuhamba kwexesha, ukubonelela uzinzo lwamaxabiso. Ke, nabani na wayenokwenza iiyunithi zemali ezintsha ngokubonelela nge-hash esebenzayo, kodwa ubunzima bokwenza i-hash bunokutshintsha ngokuhamba kwexesha ngokusekelwe kwiindleko ze-CPU kunye ne-price index, ukuze iyunithi nganye ibe 'ngatshintshiyo'.

Elinye iprojekthi edlale indima ebalulekileyo ekubunjweni kweemali zedijithali phambi kokuba kuvele i-bitcoin yi-BitTorrent.

Ngo-2001, uBram Cohen wakhupha uyilo lweprotocol ebizwa ngokuba yi-BitTorrent, eyayenzelwe ukuqhuba inkqubo yokwabelana ngeefayile phakathi kwabantu. Waqala ukusebenza kwinkampani ebizwa ngokuba yi-MojoNation, eyayimiswe ukuze abantu bakwazi ukwaphula iifayile eziyimfihlo zibe ziziqwenga ezikhuselweyo ezisasazwa kwiikhompyutha ezisebenzisa esoftware. Ikopi yefayile yayikhutshelwa ngaxeshanye kwiikhompyutha ezininzi. Nangona ekugqibeleni le projekthi yasile, yazisa uCohen kwindawo yokwabelana ngeefayile, apho wagqiba kwelokuba angakwazi ukwenza i-protocol engcono, eyayiquka:

• I-Swarm: uluntu lwezixhobo ezikhuphela okanye ezilayisha umxholo
• I-Tracker: isixhobo esizinikeleyo esisebenza ngendlela efana neenjini zokukhangela, kodwa sigcina umkhondo weefayile ezikwi-swarm. Oku kuvumela abasebenzisi ukuba babone kwaye bafikelele lula kuyo nayiphi na ifayile abayifunayo
• Umxhasi we-BitTorrent: ofakelwa kwikhompyutha ukuze ufikelele kwi-tracker. Qaphela ukuba i-swarm kuphela yindawo apho iifayile zigcinwa khona ngokwenene
• Iskimu somvuzo apho abasebenzisi abathatha inxaxheba kwinethiwekhi njengababelani beefayile bafumana ukukhuphela ngokukhawuleza

Ufaniso neBitcoin:

• Zombini ezi protocol zisebenza ngendlela yokwabelana phakathi kwabantu (peer-to-peer)
• Uyilo olungaphakathi kwabantu (decentralised design)
• Iifayile ze-BitTorrent kunye nerekhodi yeBitcoin zisasazwa kulo lonke uthungelwano
• Imvelaphi evulekileyo (open-source) (i-BitTorrent ekugqibeleni yaba software evaliweyo)

Hal Finney ngumnye wamalungu adumileyo kwintshukumo ye-Cypherpunk, owayenomdla omkhulu kuphuhliso lwemali yedijithali kwaye wayesebenzayo kuluhlu lwe-imeyile.

Wagqiba kwelokuba azame kwakhona ukuphuhlisa inkqubo yemali yedijithali esekwe kubungqina bomsebenzi (proof-of-work). Ukuza kuthi ga kweli nqanaba, isiphumo se-hash besisodwa kuyo yonke intengiselwano, kodwa ingcamango yakhe yayikukudala 'ubungqina bomsebenzi obunokusetyenziswa kwakhona'.

Ingxaki kule ndlela kukuba kukho iseva ephakathi ekufuneka ithembeke ukuba ayizukuphinda isebenzise imali enye, okanye ivaliwe. Ukuze ayigqithe le ngxaki, uHal wacebisa ukusetyenziswa kweSoftware yasimahla nevulekileyo enokubanjwa kwikhomponenti yezixhobo ezikhuselekileyo kwaye iqinisekiswe ngokuzimeleyo.

Isisombululo sasijongene neengxaki ezifanayo nezinye izindululo:

• Ingxaki ye-'chicken and egg' yokufumana ukwamkelwa, apho kungekho mvuzo okhuthaza abasebenzisi ukuba bafune iitokheni, kwaye abathengisi abafuni ukudibanisa kwinkqubo ngaphandle kokuba abasebenzisi bafuna ukuhlawula ngezi tokheni.
• I-POW nayo inokwenzeka ukuba ibe ngexabiso eliphantsi ngokuhamba kwexesha njengoko ukusebenza kweekhompyutha kuphucuka, oko kuthetha ukuba imarike inokuzaliswa ngeeyunithi zemali ze-RPOW.

Ukuba umthetho ka-Moore uyaqhubeka usebenza, iindleko zokudala i-tokheni ye-(POW) ziya kuncipha rhoqo, ngendlela ekhula ngokukhawuleza. Khumbula ukuba le ayisosimali kwaye ayenzelwanga ukuba ibe yindawo yokugcina ixabiso, koko yindlela elula yokumela umzamo wekhompyutha onokutshintshiselwa.Hal Finney

Ezi mpawu zanciphisa umtsalane kunye nokwamkelwa kweprojekthi, kwaye nangona wayezama kakhulu, le projekthi yagqibela ngokuba yenye yemizamo ehlulekile yokudala imali yedijithali.

Emva kweminyaka emininzi kunye nezamkelo ezingaphumelelanga, amaCypherpunks aye aqala ukulahlekelwa ngumdla kumxholo wemali yedijithali engenamvume, xa uAdam Back wafumana i-imeyile equlethe ikhonkco kwiphepha-mhlophe elibizwa ngokuba 'yi-electronic cash without a third party' evela kumntu ongaziwayo owayezibiza ngoSatoshi Nakamoto.

Ukushwankathela kweli nqanaba, sinemibono elandelayo:

• Iisayini zekhryptografi ezinokubonelela ngenqanaba lobumfihlo kunye nokungaziwa
• Ingcamango yemali engenaxhaso (B-Money)
• Iziphakamiso (kodwa akukho ndlela) zokulinganisa ukukhutshwa kwemali entsha
• Iinkozo zemali zedijithali ezinomnini ochongwe ngamaqhosha oluntu (B-Money) kwaye zinokuhanjiswa ngokusayina kwaye zabelwe kwakhona ngokusekelwe kwidilesi yomamkeli (RPOW kunye neHashcash)
• Zonke iinodi zigcina ikopi yencwadi-mali esasazekileyo ngokupheleleyo (B-Money) (eyayilahlwa ngelo xesha njengengasebenziyo)
• Inkqubo yokutywina ixesha– kusetyenziswa iMerkle tree hashing ukubonelela ngolandelelwano lweziganeko oluqinisekiswa ngezibalo kwaye kunzima ukulufaka isandla ukuba bonke abasebenzisi bagcina iirekhodi ezifanayo
• Ubungqina bomsebenzi bokudibanisa umzamo wokwenyani kwinkqubo (kodwa kusetyenziswa i-hash ngokwayo njengemali)
• Iinethiwekhi ezisasazekileyo ngokupheleleyo apho bonke oontanga balingana kwaye banokungena okanye ukuphuma kwinethiwekhi (BitTorrent)
• Ingcamango yokudibanisa ii-hash ezintsha kwiihash zangaphambili (Bit Gold kunye nokutywina ixesha)

Oko kwakungekhoyo ngelo xesha kubandakanya:

• Isisombululo esisebenzayo sokusombulula ingxaki 'yabaphathi baseByzantium'
• Indlela yokulinganisa imali ekwisetyenzisweni nangona izixhobo zekhompyutha zihlala ziphucuka
• Inkqubo yezikhuthazo ukuze abantu bathathe inxaxheba (ingxaki yenkukhu neqanda)

Umahluko omkhulu phakathi kwemizamo yakutshanje kunye neBitcoin kukuba uSatoshi wayesele esebenza kwikhowudi ixesha elithile ngokwenene 'amaCypherpunks abhala ikhowudi' ngaphambi kokuba ayazise kwiimeyile, ngokungafaniyo neBit Gold kunye neB-Money ezazisengcinga nje.

Yintoni inoveli eyahlula iBitcoin kwezinye iinzame zangaphambili zemali yedijithali?

Ubungqina bomsebenzi buya kusetyenziswa njengendlela yokuvumelana kunye nendlela yokubonelela ukhuseleko kunye nokungaguquki: Endaweni yokusebenzisa i-hash njengemali, iya kusetyenziswa kwinkqubo entsha ebizwa ngokuba kukumba, apho inodi iya kudibanisa iqela leentengiselwano, yongeze inani elingahleliwe kwaye isebenzise i-hash kwibhloko yedatha. Ibhloko evumelekileyo edibana neemfuno ze-hash iya kubhengezwa kwinethiwekhi. Ezi bhloko ziya kudityaniswa kusetyenziswa i-hash yebhloko yangaphambili, kwaye umxokelelwane webhloko omde uya kusetyenziswa xa kukho ukungavani apho iinodi ezahlukeneyo zivavanya kwaye zibhengeza iibhloko ezahlukeneyo ngexesha elinye ukuze kudaleke ukwahlukana komxokelelwane. Ubungqina bomsebenzi baba sisigqibo esisasazekileyo sokusombulula ingxaki yabaphathi baseByzantium.

Aba bakhasi nabo banikwa isikhuthazo sokubonelela ngeCPU efunekayo ukwenza ubungqina bomsebenzi ngokwabelwa iBitcoin entsha kwibhloko nganye. Inani leBitcoin abawufumanayo likwacwangciswe ukuba lehle rhoqo kwiminyaka emi-4 de yonke iBitcoin yenziwe, oko kudala umda onzima kwinani leBitcoin eliza kuze libe semjikelezweni, eliyi-21M.

Eyona ngcamango intsha yayikukuba usombulule njani umba wokuba imali ingakanani eyenziwayo xa izixhobo zekhompyutha ziphucuka kwaye amandla amaninzi asetyenziswa kwinethiwekhi. Amaxesha eebhloko ezili-2016 aya kumiselwa umndilili, kwaye ukuba zidalwa ngokukhawuleza kakhulu, i-hash efunekayo ukwenza ibhloko entsha iya kwenziwa inzima ngakumbi, ukuba zicotha kakhulu iya kwenziwa lula. Oku kwakwakhiwe kwinkqubo esasazekileyo eqhutywa ziinodi zonke, ngoko nawuphi na umgodi ongayilandiyo uya kuchitha amandla akhe engenanzuzo njengoko ibhloko yakhe iya kulahlwa yinxalenye yenethiwekhi. Olu lungiso luqinisekisa ukuba ukudalwa kwebhloko ezintsha kuhlala kuhambelana neshedyuli ecwangcisiweyo yokukhutshwa, kwaye lubonelela ngezikhuthazo kubagodi ukuba 'badlale ngemithetho'.

Isishwankathelo

Uninzi lwezinto ezifunekayo ukwakha inkqubo yemali yedijithali esekwe kwimigaqo yemali ezinzileyo zazisele zikho phambi kokuba uSatoshi akhuphe iphepha-mhlophe lakhe kwaye kungekudala emva kokukhutshwa kokuqala kwekhowudi.

Indalo yeBitcoin injalo ukuba kwakamsinya nje ukuba inguqulelo 0.1 yakhutshwa uyilo oluphambili lwaba lusemgangathweni ubomi bayo bonke
Satoshi Nakamoto

Nangona izimvo ezininzi zokuphucula (BIPs) ziye zaphakanyiswa kwaye zamkelwa, iBitcoin isebenza ngasemva ukusukela ngo-2009 ilandela inkqubo eyilwe kukukhutshwa kokuqala kwaye phantse akukho siphazamiso. Zonke izilungiso zenziwe ngelixa kugcinwa ukuhambelana ngasemva kuzo zonke iinguqulelo zangaphambili.

Amanqaku

1. Ngokuchaza ingxaki yabaPhathi baseByzantium - jonga https://en.wikipedia.org/wiki/Byzantine_fault