Promise278/QiCash

QiCash is a campus payment application designed to make everyday digital payments as simple as cash while using the privacy-oriented properties of QI and decentralized settlement on Quai Network. The initial target is African campus commerce, where students and small vendors make frequent low-value transactions. # QiCash **Privacy-first campus payments on Quai Network.** QiCash makes everyday digital payments as simple as cash — and as private as cash — for students and small vendors on African campuses. A student scans a vendor's QR code, pays in **native QI**, and the sale is done. Nobody — neither the network nor an onlooker — can see *who bought what, for how much, from whom*. The privacy is not an "extra layer bolted on." It is the product. QiCash is built around QI's cash-like properties (UTXO ledger, fixed denominations, prohibition of address reuse) and turns them into a QR checkout that hides the *content* of every transaction from the public ledgers that settle it. --- ## Table of contents 1. The problem 2. The experience 3. Why QI and Quai Network 4. How a payment actually works 5. The privacy model 6. Architecture 7. Security model 8. Security hardening log 9. Honest limitations 10. Getting started 11. Testing 12. Deployment 13. Roadmap --- ## The problem Students and campus vendors face a stack of payment problems: - **Digital payments expose your life.** Payment apps record every transaction — what shop, what amount, what time — and link it to your identity. - **Fees eat small purchases.** Percentage fees that barely matter on a big transfer are significant on a plate of food. - **Cash is inconvenient and unsafe.** Change, queues, theft, and no digital record. - **Crypto wallets are unusable for normal people.** Addresses, networks, gas, seed phrases, linkable activity — none of it belongs in a lunch queue. There is a gap between cash (private, simple, ubiquitous) and digital payments (convenient, but surveilled). ## The experience **Student:** open QiCash → select the campus item → scan the vendor's QR → pay → confirmed. **Vendor:** create a payment request → display the QR → detect the payment → complete the sale. Choose, scan, pay, confirmed. All blockchain complexity stays behind the interface. ## Why QI and Quai Network Quai describes QI a …