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

# Card Issuers

> Technical integration guide for card issuers implementing Vero to provide encrypted digital receipts to cardholders.

This guide covers the technical requirements and integration paths for card issuers implementing Vero.

***

## Integration Architecture

### Three integration paths

**1. Full Native Integration** (recommended)

* Add Vero SDK to existing banking app
* Receipts appear in transaction history automatically
* Typical development timeline: 2-4 weeks for experienced mobile teams

**2. Hosted Solution**

* Drop-in receipt viewer component
* Handles encryption/decryption logic
* Faster integration: 1-2 weeks

**3. API-Only**

* Webhook receiver for encrypted receipts
* Build custom UI in your app
* Maximum flexibility for custom implementations

**All approaches maintain client-side encryption, private keys never touch issuer servers.**

***

## Security & Compliance

### Cryptographic architecture

* RSA-2048 encryption with client-side key generation
* Hardware security module integration (iOS Secure Enclave, Android KeyStore)
* Private keys never leave user devices

### Compliance considerations

* GDPR-compatible design (user controls all personal data)
* PCI-DSS compatible (receipt data outside cardholder data scope)
* Cryptographic audit trail for regulatory requirements

### Fraud prevention features

* Dual signatures from merchant and issuer prevent receipt forgery
* Tamper-evident cryptographic seals
* Real-time verification of merchant legitimacy

***

## SDK Reference

### Available SDKs

* Swift (iOS) - production-ready
* Kotlin (Android) - production-ready
* JavaScript - for web-based banking portals
* API specifications for backend integration

### Developer resources

* Complete technical documentation
* Sandbox environment for testing
* Integration support

***

## Technical FAQ

> [accordion] How long does Vero integration take?
>
> **Full native integration:** 2-4 weeks for experienced mobile development teams
>
> **Hosted solution:** 1-2 weeks with drop-in components
>
> **API-only:** Timeline varies based on custom UI requirements

> [accordion] Do we need to store or manage customer private keys?
>
> No. Private keys are generated and stored exclusively on user devices in hardware security modules (iOS Secure Enclave, Android KeyStore). Your infrastructure never touches private keys.

> [accordion] How does Vero integrate with existing fraud detection systems?
>
> Vero provides itemized transaction data and dual cryptographic signatures that can be incorporated into existing fraud models. The protocol includes merchant verification and tamper-evident seals.

> [accordion] How do we handle merchants who don't support Vero yet?
>
> Vero degrades gracefully. Transactions at non-participating merchants continue normally, customers simply don't receive itemized receipts for those purchases.

> [accordion] Is Vero compliant with banking regulations and data privacy laws?
>
> Vero is designed for compliance:
>
> * **GDPR:** User controls all personal data with client-side encryption
> * **PCI-DSS:** Receipt data falls outside cardholder data scope
> * **Banking regulations:** Cryptographic audit trails support regulatory requirements
>
> Consult your compliance team for jurisdiction-specific requirements.

> [accordion] What happens if a merchant goes out of business?
>
> Receipts remain accessible to users indefinitely since they're stored client-side on user devices. The cryptographic signatures provide proof of purchase regardless of merchant status.


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