Security Considerations
Implementing robust security measures is crucial for protecting user data, preventing fraud, and ensuring safe transactions.
QR Code Security
Measures to prevent QR code tampering and unauthorized use
Required Security Measures
-
Short Expiration Time
Set QR codes to expire after 5-10 minutes to prevent replay attacks
-
Digital Signatures
Sign QR data with HMAC-SHA256 to prevent tampering
-
One-Time Use Tokens
Ensure each QR code can only be used once
Example QR Code Security Flow
flowchart TD
A[Generate QR Code] -->|Include timestamp| B{Valid?}
B -->|Yes| C[Check Signature]
B -->|No| D[Reject - Expired]
C -->|Valid| E[Check if Used]
C -->|Invalid| F[Reject - Tampered]
E -->|Not Used| G[Process Transaction]
E -->|Already Used| H[Reject - Used]
API Security
Protecting your backend APIs and machine communication
HTTPS Requirements
- Use TLS 1.2 or higher
- Valid SSL certificates
- HSTS enabled
Authentication
- API key authentication
- Machine authentication
- Token validation
Rate Limiting
- Limit requests per IP
- Machine request limits
- Prevent brute force
Data Validation
Ensuring data integrity and preventing injection attacks
Input Validation Rules
-
Validate All Incoming Requests
Check data types, lengths, and formats
-
Sanitize Data
Remove or escape special characters
-
Verify Transaction IDs
Prevent replay attacks by tracking used IDs
Example Validation Code
// Example QR data validation
function validateQRData(qrData) {
if (!qrData.appid || typeof qrData.appid !== 'string') {
throw new Error('Invalid app ID');
}
if (!qrData.timestamp ||
new Date(qrData.timestamp).getTime() < Date.now() - 600000) {
throw new Error('QR code expired');
}
if (!verifySignature(qrData)) {
throw new Error('Invalid signature');
}
// Additional validation...
}