ShariaCoProtocol

ShariaCo Protocol — AAOIFI & Fiqh Technical Compliance Dossier (Teknik Fıkhi Uyumluluk ve Akıllı Kontrat Denetim Belgesi)

DOSSIER SC-FAS28-SS08 · TECHNICAL FIQH & SMART CONTRACT AUDIT DOSSIER

Murabaha Receivable Notes, Mudarabah Vault & Defect Option (Khiyar al-Ayb)

Murabaha Alacak Senetleri, Mudaraba Kasası ve Hıyar-ı Ayb İade Güvencesi

Fixed-price deferred commodity & retail sale architecture with constructive possession, escrow hold, and on-chain unwind on defective returns.

Shariah Supervisory Registry

Independent SSB Sign-off: Scheduled / In Audit Registry

Registry ID: SC-SSB-2026-REG-01

Primary AAOIFI, OIC Fiqh Academy, and Mecelle mappings are enforced in smart contracts and gateway services. External board sign-off updates automatically from config/ssb-signoff.json.

Foundational Fiqh Maxim (Al-Qawa'id al-Fiqhiyyah)

الْخَرَاجُ بِالضَّمَانِ وَالثَّمَنُ مَعْلُومٌ عِنْدَ الْعَقْدِ

Al-kharaju bi-d-daman wa ath-thamanu ma‘lumun ‘inda al-‘aqd

Entitlement to profit requires bearing ownership/liability risk, and the sale price must be fixed and known at contract execution.

Executive Architectural Summary (EN)

Every installment purchase on Karma is executed on-chain as a fixed-price Murabaha receivable note (MurabahaNFT.sol) funded by an ERC-4626 Mudarabah capital pool (MudarabahVault.sol). Once originated via EIP-712 offer and acceptance, the total sale price (priceOf) is immutable on-chain and can never increase due to late payment or maturity extension. Merchant proceeds are held in escrow throughout the statutory return window (14, 30, or 60 days) to enforce the buyer’s Defect Option (Khiyar al-Ayb).

Teknik Fıkhi Özet (TR — Tüketici & Mağaza Yüzeyi Karşılığı)

Karma üzerindeki her taksitli alışveriş, ERC-4626 tabanlı Mudaraba sermaye havuzu (MudarabahVault.sol) tarafından fonlanan ve toplam satış bedeli sözleşme anında kilitlenen bir Murabaha alacak senedi (MurabahaNFT.sol) olarak zincire kaydedilir. İcap ve kabul tamamlandığında toplam satış bedeli (priceOf) değişmez; gecikme veya vade uzatımı sebebiyle asla artırılamaz. Mağaza hak edişi, alıcının Hıyar-ı Ayb (ayıp muhayyerliği) hakkını korumak üzere iade süresi boyunca emanet (escrow) hesabında tutulur.

1. Primary Jurisprudential & Standard Authorities

Authoritative standards from AAOIFI, OIC International Islamic Fiqh Academy (IIFA), Mecelle-i Ahkâm-ı Adliyye, and TKBB Advisory Board principles.

AAOIFIالمرابحة للآمر بالشراء

AAOIFI Shari'ah Standard No. 8 (Murabaha), Clauses 2/1, 3/1 & 4/6; AAOIFI FAS 28

Cost and profit margin must be explicitly disclosed and fixed at the moment of contract; the deferred sale price becomes a fixed debt (dayn) that cannot be increased for delay.

Maliyet ve kâr payı akid anında açıkça bildirilmeli ve sabitlenmelidir; vadeli satış bedeli zimmette sabit bir borç (deyn) haline gelir ve vade uzatımıyla artırılamaz.

AAOIFIالمضاربة المشتركة

AAOIFI Shari'ah Standard No. 13 (Mudarabah), Clauses 4 & 8

Rab al-Mal (LP) provides capital into the Mudarabah pool; profits are distributed by pre-agreed ratio while unprovoked capital loss after Takaful reserve is borne strictly by capital.

Rabbü’l-mal (likidite sağlayıcı) sermayeyi Mudaraba havuzuna koyar; kâr önceden belirlenen oranda paylaşılır, Tekâfül rezervi sonrasındaki sermaye kaybı yalnız sermayeye yansır.

MECELLEخيار العيب

Mecelle-i Ahkâm-ı Adliyye, Articles 167, 245 & 336

Art. 167: Contract is concluded by offer and acceptance (Ijab wa Qabul). Art. 245: The sale price must be known at contract. Art. 336: An unconditional sale requires the good to be free of defects (Khiyar al-Ayb).

Md. 167: İcap ve kabul ile akid tamam olur. Md. 245: Bey’de semenin malum olması şarttır. Md. 336: Mutlak akid, mebiin ayıptan salim olmasını iktiza eder (Hıyar-ı Ayb).

TKBB

TKBB Advisory Board — Murabaha & Electronic Commerce Principles

Constructive possession (Qabd Hukmi) and transparent disclosure of cash vs. installment price prior to binding confirmation.

Hükmi kabz şartlarının sağlanması ve bağlayıcı onay öncesinde peşin ile vadeli toplam satış bedelinin şeffaf biçimde gösterilmesi.

2. Fiqh Ruling → Solidity Function & Gateway Enforcement Matrix

Direct line-by-line mapping between classical/contemporary Islamic commercial rulings and executable smart contract / gateway invariants.

Fiqh RulingStandard RefSource File & LineSolidity / Service SignatureOn-Chain / Runtime Enforcement
Offer & Acceptance (Ijab wa Qabul)
الإيجاب والقبول
Mecelle Art. 167 · AAOIFI SS 8 §3/1src/MurabahaNFT.sol:198originate(OriginationParams, bytes buyerSig, bytes clearanceSig) / hashOriginate(...)Verifies EIP-712 buyer offer digest and AI Engine Shariah/risk clearance signature before minting the receivable note.
Immutable Deferred Sale Price (Thaman Ma‘lum)
ثمن معلوم ثابت
Mecelle Art. 245 · AAOIFI SS 8 §4/6src/MurabahaNFT.sol:262priceOf(uint256 tokenId) / payInstallment(uint256 tokenId) / repayPartial(uint256 tokenId, uint256 wad)Sale price is written once at origination; no contract function can increase priceOf(tokenId) after minting.
Earnest Money & Title Tracking (Hamish Jiddiyyah)
هامش الجدية
AAOIFI SS 8 §2/5/3src/MurabahaNFT.sol:274hamishOf(uint256 tokenId) / titleOf(uint256 tokenId) / payerOf(uint256 tokenId)Records down-payment/earnest money separately and tracks payer address so refunds return strictly to the original payer.
Defect Option & Escrow Unwind (Khiyar al-Ayb)
خيار العيب والفسخ
Mecelle Art. 336 · AAOIFI SS 8 §3/2src/MurabahaNFT.sol:380requestReturn(tokenId) → objectReturn(tokenId) → finalizeReturn(tokenId) / refundOrder(tokenId) / releaseToMerchant(tokenId)Holds merchant settlement in escrow during the return window (14/30/60d). Validated returns unwind the note and refund the buyer without penalty.
Mudarabah Capital Pool & Loss Attribution
رأس مال المضاربة
AAOIFI SS 13 §8 · FAS 28src/MudarabahVault.sol:142deposit(uint256, address) / writeOffPrincipal(uint256) / requestRedeem(uint256) / processRedemptionQueue(uint256)ERC-4626 vault minting vMDB shares (+6 decimals offset). FIFO redemption queue prevents liquidity runs while preserving NAV accounting.

3. Machine-Checked Protocol Invariants

  • [INV]priceOf(tokenId) is strictly immutable after originate(); zero storage mutators exist to increase total debt.
  • [INV]Fair-margin cap (Gabn-i Fahis guard) in pricing_engine.py bounds monthly markup to <= 3.0% before any clearance signature is issued.
  • [INV]Merchant proceeds remain locked until returnWindow elapses or releaseToMerchant(tokenId) is eligible without active return dispute.

4. Supervisory Board Attestation

ShariaCo Independent Shariah Supervisory Board (SSB)SC-SSB-2026-REG-01

Independent SSB Sign-off: Scheduled / In Audit Registry

This technical dossier documents the exact AAOIFI, OIC Islamic Fiqh Academy, and Mecelle rules compiled into the ShariaCo smart contracts. Independent Shariah Supervisory Board (SSB) wet-ink member sign-offs are scheduled in the audit registry (`config/ssb-signoff.json`).