> ## Documentation Index
> Fetch the complete documentation index at: https://docs.digitalreceiptprotocol.org/llms.txt
> Use this file to discover all available pages before exploring further.

> An open, consent-driven standard for encrypted, portable, and verifiable digital receipts.

# Digital Receipt Protocol (DRP)

### What is DRP?

DRP is an open protocol that enables merchants to send encrypted, itemized receipts directly to customers' banking apps during transactions. Like OAuth standardized authentication and HTTP standardized web communication, DRP provides a standard layer for receipt data ownership.

**Technical foundation:**

* Client-side encryption with RSA-2048 (private keys never leave user devices)
* Hardware security module integration (iOS Secure Enclave, Android KeyStore)
* Dual signatures from merchants and issuers for verification
* JSON-LD for semantic interoperability
* Open-source protocol with no vendor lock-in

***

### The Problem DRP Solves

Current digital receipt systems store user data on merchant or third-party servers. Users don't truly own their transaction history—they're granted access to corporate databases. This creates friction for expense reporting, disputes, returns, and data portability.

DRP provides cryptographic ownership: users hold the only key to decrypt their receipts. Receipts are verified, itemized, and portable without compromising privacy or security.

***

### How It Works

#### Four-Step Flow

1. **Transaction occurs** - Customer pays at merchant POS
2. **Receipt generated** - Merchant creates itemized receipt, signs with their private key
3. **Encrypted transmission** - Receipt encrypted with user's public key, sent to issuer
4. **User decryption** - Only user can decrypt receipt in their banking app with private key stored in device hardware

<Card title="See the Sequence Diagram" icon="arrow-up-right-from-square" href="https://drp-banking-demo.vercel.app/" target="_blank">
  View the full flow from payment intent through receipt viewing
</Card>

***

### Protocol Participants

**Card Issuers:** Integrate SDK to provide receipt viewing in banking apps

**Merchants:** Send cryptographically signed receipts through POS systems

**POS Systems:** Provide plugin or native integration for receipt generation

**End Users:** Receive encrypted receipts with full data ownership

***

## Get Started

<Card title="Quick Start Guide" icon="rocket" horizontal href="/quickstart">
  Follow the integration guide for your role in the ecosystem.
</Card>

## Integration Guides

<Columns cols={2}>
  <Card title="Card Issuers" icon="building-columns" href="/essentials/card-issuers">
    SDK integration for banking apps
  </Card>

  <Card title="End Users" icon="user" href="/essentials/end-user">
    Understanding receipt ownership and portability
  </Card>

  <Card title="Merchants" icon="shop" href="/essentials/merchants">
    Receipt signing and transmission
  </Card>

  <Card title="POS Systems" icon="cash-register" href="/essentials/pos-systems">
    Plugin and native integration options
  </Card>
</Columns>

***

### Frequently Asked Questions

<AccordionGroup>
  <Accordion title="How is DRP different from existing digital receipt solutions?">
    Existing solutions store receipts on merchant or third-party servers—you're granted access, not ownership. DRP uses client-side encryption where your private key never leaves your device. Merchants, banks, and even DRP cannot decrypt your receipts.
  </Accordion>

  <Accordion title="Is DRP a proprietary platform or vendor?">
    No. DRP is an open-source protocol, like HTTP or OAuth. There's no vendor lock-in, no transaction fees, and no licensing costs. The protocol is being submitted for W3C standardization.
  </Accordion>

  <Accordion title="What if my bank doesn't support DRP yet?">
    You can use an open-source reference wallet app to receive and store receipts independently. Once your bank integrates DRP, you can migrate your receipt history since you control the private keys.
  </Accordion>

  <Accordion title="How does DRP handle receipt data from before it was implemented?">
    DRP includes retroactive encryption capability. When issuers integrate DRP, they can encrypt existing receipt data from transaction history and deliver it to users.
  </Accordion>

  <Accordion title="What happens if I switch banks or credit cards?">
    Receipts are portable. Export your encrypted receipt history in JSON-LD format and import it into your new banking app. True ownership means your data travels with you.
  </Accordion>
</AccordionGroup>