Alƙawuran Bitcoin Ba tare da Ƙuntatawa ba: Tsarin Ƙa'ida don Ƙwararrun Kwangilolin Smart

1. Gabatarwa

Tsarin Fitowar Ma'amalar da ba a ciyar da ita (UTXO) na Bitcoin, ko da yake yana da kyau don canja wurin kuɗi a lokaci guda, yana gabatar da ƙuntatawa mai mahimmanci don aiwatar da ƙwararrun kwangilolin smart masu ɗaukar jiha saboda rashin raba jihar mai canzawa. Alƙawurai suna fitowa a matsayin muhimmin tushen harshe da aka ba da shawara don faɗaɗa Rubutun Bitcoin, yana ba da damar ma'amala ta sanya ƙuntatawa akan rubutun ma'amalolin cirewa na gaba. Wannan takarda tana magance gibin da ke cikin ƙa'idodin ƙa'ida na alƙawurai, waɗanda aka bayyana su da farko daga ra'ayi na ƙananan matakan, mai mai da hankali kan aiwatarwa tun lokacin da aka ƙirƙira su a kusan 2013. Ta hanyar samar da tushe na ƙa'ida, aikin yana nufin sauƙaƙe tunani game da kaddarorin kwangila, ba da damar ƙayyadaddun amfani da suka wuce iyawar Bitcoin na yanzu, da sauƙaƙe ƙirar ƙwararrun rabe-raben shirye-shirye.

2. Tsarin Bitcoin Tsantsa

Takardar ta daidaita ƙirar ƙa'ida na ainihin tsarin ma'amalar Bitcoin. A cikin tsarin UTXO, ana bayyana jihar blockchain ta hanyar saitin fitowar ma'amalar da ba a ciyar da ita. Kowane fitowa ya ƙunshi ƙima (adadin bitcoin) da scriptPubKey (rubutun kullewa) wanda ke ƙayyade sharuɗɗan da ake buƙata don ciyar da shi. Ma'amalar ciyarwa tana ba da scriptSig (rubutun buɗewa) kuma tana nuni ga UTXO da take son cinyewa. Tabbatarwa ya haɗa da aiwatar da rubutun da aka haɗa. Muhimmin abu, daidaitaccen Rubutun Bitcoin yana da iyaka: ba zai iya bincika ko ƙuntata tsarin ma'amalar ciyarwa fiye da tabbatar da sa hannu da lissafi/mantiki na asali ba, yana hana ƙirƙirar kwangilolin da ke tilasta ka'idoji masu matakai da yawa.

3. Tsarin Ƙa'ida na Alƙawurai

Babban gudunmawar shine ƙirar ƙa'ida wacce ke ɗauke da ƙa'idodin alƙawuri da aka ba da shawara (kamar OP_CHECKTEMPLATEVERIFY).

3.1. Tushen Alƙawuri & Tsarin Magana

Ƙirar ta gabatar da tsinkayen alƙawuri a matsayin ƙari ga Rubutun Bitcoin. Alƙawuri a zahiri ƙuntatawa ne $C(T_x, T_{next})$ wanda ke kimanta zuwa gaskiya ko ƙarya, inda $T_x$ shine ma'amalar da ake ciyarwa a yanzu kuma $T_{next}$ shine ma'amalar ciyarwa da aka ba da shawara. Tsinkaya na iya duba filayen $T_{next}$, kamar rubutun fitarwa, adadi, ko lokutan kullewa.

3.2. Ma'anar Aiki

An faɗaɗa ƙa'idar tabbatarwa: Don UTXO mai alƙawuri, tabbatar da ma'amalar ciyarwa $T_{next}$ yana buƙatar ba kawai cewa scriptSig ɗinsa ya gamsar da ainihin scriptPubKey ba har ma cewa tsinkayar alƙawuri $C$ ya kasance gaskiya ga ma'auratan $(T_x, T_{next})$. An bayyana wannan bisa ƙa'ida ta amfani da ƙa'idodin ma'anar aiki waɗanda ke haɗa binciken alƙawuri cikin dabarar tabbatarwa ta Bitcoin da ke akwai.

3.3. Alƙawuran Maimaitawa & Injunan Jihohi

Bambance-bambancen mai ƙarfi shine alƙawurin maimaitawa, inda $C$ zai iya tilasta cewa fitowar $T_{next}$ da kanta ta ƙunshi alƙawuri ɗaya (ko alaƙa) $C'$. Wannan yana ba da damar aiwatar da injunan jihohi akan Bitcoin: kowane ma'amala yana wakiltar sauyin jiha, tare da alƙawurin tabbatar da ana bin ƙa'idodin injin jihohi a cikin sarkar ma'amaloli. Takardar ta ƙirƙira wannan a matsayin jerin ma'amaloli $T_1, T_2, ..., T_n$ inda ga kowane $i$, $C(T_i, T_{i+1})$ ya kasance gaskiya.

4. Ƙayyadaddun Ƙwararrun Kwangilolin Bitcoin

An yi amfani da ƙirar ƙa'ida don ƙayyade kwangilolin da ba za a iya bayyana su ko kuma suka yi wuya a cikin Bitcoin tsantsa.

4.1. Taskoki & Cire Kuɗi Mai Ƙullewar Lokaci

Alƙawurai na iya ƙirƙirar "taskoki" inda za a iya dawo da kuɗaɗen da aka sace. Ma'amala na iya buƙatar cewa duk wani babban cirewa dole ne da farko ya je zuwa fitowar da aka kulle lokaci, yana ba mai shi damar soke shi idan ba a ba da izini ba. An ƙayyade wannan ta hanyar alƙawuri wanda ke duba filin nLockTime da tsarin fitarwa na $T_{next}$.

4.2. Tashoshin Biyan Kuɗi & Cibiyar Sadarwar Walƙiya

Duk da yake Cibiyar Sadarwar Walƙiya ta wanzu, alƙawurai na iya sauƙaƙa da kuma kiyaye ginin da ke ƙarƙashinta. Za su iya tilasta cewa ma'amalar rufe tashar dole ne ta zama jihar da ta fi kwanan nan, tare da hana watsa tsohuwar jiha, ta hanyar ƙuntata ma'amalar ciyarwa don dacewa da sabuntawa da aka riga aka sanya hannu.

4.3. Tushen Kuɗi Na Rarraba (DeFi)

Gine-ginen DeFi masu sauƙi kamar bashi mai lamuni ko musayar da ba ta da kulawa sun zama mai yiwuwa. Alƙawuri na iya kulle kuɗaɗe a cikin ma'amala wanda za a iya ciyar da shi kawai ta hanyar ma'amala da ke gabatar da ingantaccen hujjar sirri na biyan kuɗi daga ɗayan ɓangaren ko na rarrabawa.

5. Tushen Harshe na Babban Matakin

Takardar tana tattauna yadda alƙawurai za su iya zama manufa ta haɗawa don harsunan kwangila na babban matakin. Tushen kamar "cire bayan lokaci T", "ciya kawai idan ɗayan ɓangaren ya sanya hannu", ko "canza jiha daga A zuwa B" ana iya ƙetare su kai tsaye zuwa takamaiman ƙuntatawar alƙawuri, yana ɗaga matakin rabe-rabe ga masu haɓaka kwangilolin Bitcoin.

6. Fahimtar Tushe & Ra'ayin Mai Bincike

Fahimtar Tushe: Bartoletti da sauransu ba kawai suna ba da shawarar wani ƙa'idar alƙawuri ba; suna isar da ka'idar ƙa'ida da ta ɓace wacce ke mai da wayo na dabarar zama ingantaccen tsarin shirye-shirye na Bitcoin wanda za a iya bincika. Wannan shine makullin da ke buɗe injiniyanci na tsari na ƙwararrun kwangiloli masu tsaro akan sarƙoƙin UTXO, ya wuce rubutun ad-hoc.

Tsarin Ma'ana: Hujjar tana da ban sha'awa mai sauƙi: 1) Tsarin UTXO na Bitcoin ba shi da jiha, yana iyakance kwangiloli. 2) Alƙawuran da aka ba da shawara a matsayin gyara ba a fahimta sosai bisa ƙa'ida. 3) Saboda haka, mun gina ƙirar ƙa'ida. 4) Ta amfani da wannan ƙirar, mun nuna cewa tana iya bayyana amfani mai mahimmanci, ƙwararrun amfani (taskoki, tashoshi, DeFi). 5) Wannan ƙa'idar sai ta ba da damar ƙirar harshe na babban matakin. Yana da kyau "ka'ida tana ba da damar aiki" bututun da aka aiwatar da daidaito.

Ƙarfi & Kurakurai: Babban ƙarfi shine haɗa gibin tsakanin ilimin sirri/ka'idar PL da injiniyan Bitcoin—gibin da ya haifar da ɓarnatattun kwayoyi a cikin ƙirar asusun Ethereum. Ma'anar ƙa'ida tana ba da damar tabbatar da kadarori, babban nasara. Kuskuren, wanda aka yarda da shi a ɓoye, shine tsarin siyasar tattalin arziki na Bitcoin. Kamar yadda takardar ta lura, "tsarin Bitcoin mai tsananin taka tsantsan" ya sa aiwatar da sabbin ƙa'idodi kamar alƙawuri ya zama aiki mai wuyar gaske, ba tare da la'akari da kyawun ƙa'idar su ba. Nasarar Layer-2s kamar Walƙiya ba tare da alƙawuran asali ba kuma yana tayar da tambayoyi game da larura da kyau. Bugu da ƙari, tsaron ƙirar ya dogara ne akan zato cewa filayen da aka ƙuntata (kamar hasashin rubutu) sun isa; tasirin hulɗar da ba a zata ba tare da wasu ƙa'idodi na iya kasancewa.

Fahimta Mai Aiki: Ga masu bincike, wannan takarda tsari ne: yi amfani da hanyoyin ƙa'ida don rage haɗari da fayyace haɓakar blockchain. Ga masu haɓakawa, fara ƙirar tsarin kwangila yanzu suna ɗauka cewa alƙawurai za su wanzu (kamar yadda aka gani akan Liquid ko Stacks). Ga masu haɓaka ƙa'idar Bitcoin, takardar tana ba da ingantaccen tushen da ake buƙata don yin jayayya don BIP 119 (OP_CTV) ko makamantansu—tana canza buƙatar fasali zuwa ƙayyadaddun injiniya. Babban abin da za a ɗauka: makomar ƙwararrun kwangilolin Bitcoin ba game da kwaikwayon Ethereum ba ne, amma game da yin amfani da ƙa'idar UTXO+alƙawuri na musamman don ƙirƙirar sabon nau'in aikace-aikacen rarraba, mai yuwuwar mafi tsaro da ma'auni.

7. Cikakkun Bayanai na Fasaha & Ƙirƙirar Ƙa'ida

Ƙirar ƙa'ida tana bayyana ma'amaloli, rubutun, da tabbatarwa bisa mahallin. Wani muhimmin bayani na fasaha shine wakilcin ƙuntatawar alƙawuri. Bari $\texttt{tx}$ ya wakilci ma'amala. Ana iya ganin alƙawuri a matsayin aiki:

$\text{Covenant}_{\text{cond}} : \texttt{tx}_{\text{current}} \times \texttt{tx}_{\text{next}} \times \sigma \rightarrow \{\text{True}, \text{False}\}$

inda $\sigma$ ke wakiltar mahallin tabbatarwa (tsayin toshe, da sauransu). Tsinkaya $\text{cond}$ na iya zama haɗin bincike akan filayen $\texttt{tx}_{\text{next}}$:

$\text{cond} \equiv (\texttt{hashOutputs}(\texttt{tx}_{\text{next}}) = H) \land (\texttt{nLockTime}(\texttt{tx}_{\text{next}}) > T) \land ...$

Wannan ya yi daidai da shawarwari kamar OP_CHECKTEMPLATEVERIFY, wanda ke tura hasashin sassan da aka ƙayyade na ma'amalar ciyarwa akan tarin don kwatanta. An ƙirƙira kadarorin maimaitawa ta hanyar tabbatar da cewa fitowar $\texttt{tx}_{\text{next}}$ ya ƙunshi rubutu $S'$ wanda da kansa yana tilasta alƙawuri $\text{Covenant}_{\text{cond}'}$.

8. Tsarin Bincike & Misalin Hali

Misali: Kwangilar Taska Mai Sauƙi
Manufa: Ƙirƙiri UTXO wanda za a iya ciyar da shi ta hanyoyi biyu: 1) Nan take, amma kawai zuwa takamaiman adireshin "ma'ajiyar sanyi". 2) Zuwa kowane adireshi, amma kawai bayan jinkiri na kwanaki 30 (yana ba da damar soke sata).
Aiwatar Tsarin ta Amfani da Ƙirar Ƙa'ida:
1. Ainihin Rubutun Kullewa (scriptPubKey): Ya ƙunshi sharadi na alƙawuri $C_1$.
2. Alƙawuri $C_1(T_{vault}, T_{spend})$: Dole ne ya kimanta zuwa Gaskiya. Yana bincika:
a) Hanya A (Nan take): $\texttt{hashOutputs}(T_{spend}) = H_{cold}$ // Fitowa dole ne ta yi hashe zuwa adireshin ma'ajiyar sanyi da aka riga aka yi alkawari.
b) Hanya B (Jinkiri): $\texttt{nLockTime}(T_{spend}) \geq \text{currentBlock} + 4320$ (kwanaki 30 a cikin tubalan) KUMA $\texttt{hashOutputs}(T_{spend})$ na iya zama komai.
3. Tabbatarwa: Lokacin ciyar da UTXO na taska tare da $T_{spend}$, kumburin Bitcoin yana aiwatar da rubutun. Yana buƙatar sa hannu daga mai taska kuma yana tabbatar da cewa $C_1$ ya kasance gaskiya ga ma'auratan ma'amala.
Wannan misalin yana nuna yadda ƙirar ƙa'idar tsinkaya $C(T_x, T_{next})$ aka ƙaddara tare da takamaiman bincike akan filayen ma'amala ta gaba, yana ba da damar kadarorin tsaro (dawo da sata) wanda ba zai yiwu a cikin Bitcoin na asali ba.

9. Ayyukan Gaba & Hanyoyi

Ƙirƙirar ƙa'ida ta buɗe hanyoyi da yawa na gaba:

Masu Haɗawa da aka Tabbatar: Gina masu haɗawa daga harsuna na babban matakin (kamar Simplicity ko ƙari na Miniscript) zuwa Rubutun Bitcoin da aka haɗa da alƙawuri, tare da hujjojin gaskiya na daidaito.
Alƙawuran Ƙetare Sarƙoƙi: Bincika alƙawuran da ke ƙuntata ciyarwa akan abubuwan da suka faru daga wasu sarƙoƙi ko masu duba, ta amfani da hujjojin sirri kamar SPVs, kamar yadda aikin farko akan "gadoji" da binciken kwanan nan akan rollups ya nuna.
Alƙawuran Kiyaye Sirri: Haɗa binciken alƙawuri tare da hujjojin rashin sani (misali, ta amfani da sa hannun Taproot/Schnorr) don ɓoye dabarar kwangila yayin da har yanzu ana tilasta ta, hanyar da ake bincika a cikin ayyuka kamar Ark.
Binciken Tsaro na Ƙa'ida: Yin amfani da ƙirar don bincika tsarin tsaro na gine-ginen alƙawuri da aka ba da shawara a kan hare-haren tattalin arziki da sirri, kama da aikin da aka yi akan ƙwararrun kwangilolin Ethereum ta al'ummar IEEE Symposium on Security and Privacy.
Sauƙaƙe Ƙa'idar Layer-2: Sake ƙirar ƙa'idodi kamar Cibiyar Sadarwar Walƙiya ko ɓangaren sarƙoƙi (Liquid) don zama mafi inganci da rage amincewa ta hanyar amfani da alƙawuran asali, rage buƙatar hadaddun hasumiya ko tarayya.

10. Nassoshi

M. Bartoletti, S. Lande, R. Zunino. Alƙawuran Bitcoin Ba tare da Ƙuntatawa ba. arXiv:2006.03918v2 [cs.PL]. 2020.
S. Nakamoto. Bitcoin: Tsarin Kuɗin Lantarki na Peer-to-Peer. 2008.
J. Poon, T. Dryja. Cibiyar Sadarwar Walƙiya ta Bitcoin: Biyan Kuɗi Nan take na Kashe-Layin Ma'auni. 2016.
M. Moser, I. Eyal, E. G. Sirer. Alƙawuran Bitcoin. Tarurrukan Kwamitin Kuɗi na 2016.
Shawara na Haɓaka Bitcoin 119 (BIP 119). OP_CHECKTEMPLATEVERIFY.
G. Wood. Ethereum: Tsarin Ma'amalar Gabaɗaya na Rarraba mai Tsaro. Takardar Yellow Ethereum. 2014.
A. Miller, da sauransu. Kwangilolin Ƙullewar Lokaci da aka Yi Hash (HTLCs). 2017.
R. O'Connor. Simplicity: Sabon Harshe don Sarƙoƙi. Proceedings of the 2017 Workshop on Programming Languages and Analysis for Security.
Blockstream. Cibiyar Sadarwar Liquid. https://blockstream.com/liquid/
IEEE Symposium on Security and Privacy. Takardu da yawa akan binciken tsaro na kwangilolin smart. Shekaru daban-daban.