Security & credit (tawthīqāt)

These are the contracts that surround a debt without becoming interest on it. The recurring rule is severe and simple: a loan returns its like, no more. “Every loan that draws a benefit is riba.” So the collateral earns the creditor nothing, the guarantor takes no fee, the transfer of a debt carries no increase, and the safekeeping deposit is a trust the custodian may not touch. Each is a place where a benefit could quietly attach to a loan. The engine refuses the attachment.

Note

Citations are [scholar-verify]; the engine proves consistency, not a fatwa.

Qarḍ ḥasan (qard_hasan)

A benevolent loan. The lender disburses a sum; the borrower repays in like, exactly the principal, no more. Any stipulated increase, or any fee or benefit conditioned on the loan, is riba. An unstipulated gift at repayment is licit, and is not modelled here.

Code	What it guards
QARD-1	returns { loan { principal; repayment; stipulated_increase; fee } } present.
QARD-2	no fee is tied to the loan: “every loan that draws a benefit is riba.”

qard_hasan.fiqh: consistent

returns {
  loan {
    principal:           1000000;
    repayment:           principal;  // repaid in like, no increase
    stipulated_increase: none;
    fee:                 none;
  }
}

Rahn (rahn)

A pledge or collateral. The pledgor (al-rāhin) pledges an asset (marhūn) to secure a debt held by the pledgee (al-murtahin). The pledge is security, not a profit centre. The creditor takes no benefit from it, since a benefit to the creditor would be riba on the loan, and on default it is sold to satisfy the debt with any surplus returning to the pledgor. The pledge is not forfeit (lā yaghlaqu al-rahn).

Code	What it guards
RAHN-1	returns { pledge { debt; pledge_value; creditor_use; surplus } } present, with creditor_use: none.
RAHN-2	the surplus over the debt returns to the pledgor (the pledge is not forfeit).
RAHN-3	a positive debt and pledge_value.

rahn.fiqh: the load-bearing terms

returns {
  pledge {
    debt:         1000000;
    pledge_value: 1200000;
    creditor_use: none;       // the creditor derives NO benefit (else riba)
    surplus:      to_pledgor; // on default, surplus over the debt returns to the pledgor
    liability:    amanah;     // a trust in the creditor's hand (majority view)
  }
}

Kafāla / ḍamān (kafala)

Suretyship. The guarantor (kafīl) gratuitously assumes the debtor’s obligation to the creditor. The majority forbid a fee for the guarantee itself, since it is a benefit on lent credit and can mask riba. Al-zaʿīm ghārim: the guarantor is liable. On paying the creditor at default, the guarantor recovers from the debtor exactly what he paid, with no surcharge.

Code	What it guards
KAFALA-1	returns { guarantee { amount; fee; recourse } } present, with fee: none.
KAFALA-2	recourse is actual_paid; a surcharge would be riba.

kafala.fiqh: consistent

returns {
  guarantee {
    amount:   1000000;
    fee:      none;         // no fee for the guarantee itself
    recourse: actual_paid;  // recover exactly what was paid, no surcharge
  }
}

Ḥawāla (hawala)

Assignment or transfer of debt. The original debtor (al-muḥīl) refers his creditor to a third party who owes him, and on acceptance the original debtor is discharged. The transfer is for the like of the debt, with no increase, since an increase would be a riba-bearing sale of debt.

Code	What it guards
HAWALA-1	returns { transfer { debt; amount; discharge } } present.
HAWALA-2	the transfer discharges the original debtor (al-muḥīl).

hawala.fiqh: consistent

returns {
  transfer {
    debt:      1000000;
    amount:    1000000;          // equals the debt, no increase
    discharge: original_debtor;  // a valid hawala discharges the muḥīl
  }
}

Wadīʿa (wadia)

A safekeeping deposit. The depositor entrusts property to the custodian. The deposit is a trust (yad amāna), so the custodian is not liable for its loss absent taʿaddī or taqṣīr, and may not use it. Declaring it “guaranteed,” or using it, turns the contract into a loan (qarḍ), at which point any conditioned benefit is riba. A fee for the safekeeping service is permitted (wadīʿa bi-l-ujra) and is not modelled here.

Code	What it guards
WADIA-1	returns { deposit { amount; liability; custodian_use } } present.
WADIA-2	the custodian must not use the deposit (using it is taʿaddī and, if arranged, makes it a loan).

wadia.fiqh: consistent

returns {
  deposit {
    amount:        1000000;
    liability:     amanah;   // a trust, not guaranteed (else it becomes a loan)
    custodian_use: none;     // the custodian must not use the deposit
  }
}