Security Model

Link2Pay implements a comprehensive security model designed to protect merchants, customers, and the payment infrastructure from common threats while maintaining the decentralized and trustless properties of the Stellar network.

Overview

Link2Pay's security architecture is built on multiple layers of defense:

Security Principles

Defense in Depth: Multiple security layers prevent single points of failure
Least Privilege: Components and users have minimal required permissions
Zero Trust: All requests are authenticated and validated
Cryptographic Verification: All signatures and payments are cryptographically verified
Transparency: Security model is documented and auditable

Threat Model

Assets to Protect

Primary Assets:

Merchant funds and wallet keys
Customer payment information
API credentials and session tokens
Invoice and payment data
Webhook endpoints and secrets

Secondary Assets:

User session data
Transaction metadata
Analytics and metrics
System availability

Threat Actors

External Attackers:

Attempting to steal funds
Trying to compromise accounts
Performing DoS attacks
Intercepting payment data

Malicious Merchants:

Creating fraudulent invoices
Manipulating payment amounts
Phishing customers

Compromised Customers:

Stolen wallet credentials
Malware on client device
Man-in-the-middle attacks

Attack Vectors

Network Attacks
- Man-in-the-middle (MITM)
- DNS spoofing
- SSL stripping
- DDoS attacks
Application Attacks
- SQL injection
- XSS (Cross-Site Scripting)
- CSRF (Cross-Site Request Forgery)
- Session hijacking
- API abuse
Cryptographic Attacks
- Signature forgery
- Replay attacks
- Nonce reuse
- Key extraction
Social Engineering
- Phishing
- Invoice fraud
- Support impersonation

Authentication Security

Wallet-Based Authentication

Link2Pay uses cryptographic signatures for passwordless authentication:

typescript

// Authentication flow with security measures
async function authenticate(walletAddress: string) {
  // 1. Nonce generation with expiry
  const nonce = crypto.randomBytes(32).toString('hex');
  const expiresAt = Date.now() + 5 * 60 * 1000; // 5 minutes

  await redis.setex(
    `nonce:${nonce}`,
    300, // 5 minutes TTL
    JSON.stringify({ walletAddress, expiresAt })
  );

  // 2. Build message with timestamp
  const timestamp = Date.now();
  const message = `Link2Pay Authentication\n` +
    `Wallet: ${walletAddress}\n` +
    `Nonce: ${nonce}\n` +
    `Timestamp: ${timestamp}\n` +
    `This signature will not be used for any transactions.`;

  return { nonce, message, expiresAt };
}

async function verifyAuthentication(
  walletAddress: string,
  nonce: string,
  signature: string
) {
  // 1. Verify nonce hasn't been used
  const nonceData = await redis.get(`nonce:${nonce}`);
  if (!nonceData) {
    throw new Error('Invalid or expired nonce');
  }

  const { walletAddress: storedAddress, expiresAt } = JSON.parse(nonceData);

  // 2. Verify nonce belongs to this wallet
  if (storedAddress !== walletAddress) {
    throw new Error('Nonce does not match wallet');
  }

  // 3. Verify nonce hasn't expired
  if (Date.now() > expiresAt) {
    throw new Error('Nonce has expired');
  }

  // 4. Verify signature
  const keypair = Keypair.fromPublicKey(walletAddress);
  const message = buildMessage(walletAddress, nonce);
  const isValid = keypair.verify(
    Buffer.from(message, 'utf-8'),
    Buffer.from(signature, 'hex')
  );

  if (!isValid) {
    throw new Error('Invalid signature');
  }

  // 5. Invalidate nonce (one-time use)
  await redis.del(`nonce:${nonce}`);

  // 6. Issue session token
  const token = jwt.sign(
    {
      walletAddress,
      iat: Math.floor(Date.now() / 1000),
      exp: Math.floor(Date.now() / 1000) + 3600 // 1 hour
    },
    JWT_SECRET,
    { algorithm: 'HS256' }
  );

  return { token };
}

Security Features

Nonce Management:

Cryptographically random (32 bytes)
Single-use only
Time-limited (5 minutes)
Stored in Redis with TTL
Wallet-bound

Session Tokens:

JWT with HMAC-SHA256
1-hour expiration
Includes issued-at timestamp
Refresh token rotation
Secure storage requirements

Rate Limiting:

typescript

// Rate limiting configuration
const rateLimits = {
  nonce: {
    windowMs: 15 * 60 * 1000, // 15 minutes
    max: 10, // 10 nonce requests per window
    message: 'Too many authentication attempts'
  },
  verify: {
    windowMs: 15 * 60 * 1000,
    max: 20, // 20 verification attempts per window
    message: 'Too many verification attempts'
  },
  login: {
    windowMs: 15 * 60 * 1000,
    max: 5, // 5 failed logins per window
    skipSuccessfulRequests: true
  }
};

// Implementation with express-rate-limit
app.post('/auth/nonce',
  rateLimit(rateLimits.nonce),
  nonceController
);

app.post('/auth/verify',
  rateLimit(rateLimits.verify),
  verifyController
);

Payment Security

Payment Verification

Every payment is cryptographically verified on the Stellar network:

typescript

// Comprehensive payment verification
async function verifyPayment(
  transactionHash: string,
  invoice: Invoice
): Promise<PaymentVerificationResult> {
  try {
    // 1. Fetch transaction from Stellar network
    const transaction = await server
      .transactions()
      .transaction(transactionHash)
      .call();

    // 2. Verify transaction succeeded
    if (!transaction.successful) {
      return {
        valid: false,
        error: 'TRANSACTION_FAILED',
        details: 'Transaction was not successful on Stellar network'
      };
    }

    // 3. Load and verify operations
    const operations = await transaction.operations();
    const paymentOp = operations.records.find(
      op => op.type === 'payment'
    );

    if (!paymentOp) {
      return {
        valid: false,
        error: 'NO_PAYMENT_OPERATION',
        details: 'Transaction does not contain a payment operation'
      };
    }

    // 4. Verify recipient matches merchant
    if (paymentOp.to !== invoice.merchantAddress) {
      return {
        valid: false,
        error: 'RECIPIENT_MISMATCH',
        expected: invoice.merchantAddress,
        actual: paymentOp.to
      };
    }

    // 5. Verify amount matches invoice
    const actualAmount = new BigNumber(paymentOp.amount);
    const expectedAmount = new BigNumber(invoice.amount);

    if (!actualAmount.isEqualTo(expectedAmount)) {
      return {
        valid: false,
        error: 'AMOUNT_MISMATCH',
        expected: expectedAmount.toString(),
        actual: actualAmount.toString()
      };
    }

    // 6. Verify asset matches
    const actualAsset = paymentOp.asset_code || 'XLM';
    if (actualAsset !== invoice.asset) {
      return {
        valid: false,
        error: 'ASSET_MISMATCH',
        expected: invoice.asset,
        actual: actualAsset
      };
    }

    // 7. Verify timestamp within acceptable range
    const txTimestamp = new Date(transaction.created_at).getTime();
    const invoiceCreated = new Date(invoice.createdAt).getTime();
    const invoiceExpiry = new Date(invoice.expiresAt).getTime();

    if (txTimestamp < invoiceCreated || txTimestamp > invoiceExpiry) {
      return {
        valid: false,
        error: 'TIMESTAMP_OUT_OF_RANGE',
        details: 'Payment timestamp outside invoice validity period'
      };
    }

    // 8. Check for memo (optional)
    if (invoice.memo && transaction.memo !== invoice.memo) {
      return {
        valid: false,
        error: 'MEMO_MISMATCH',
        expected: invoice.memo,
        actual: transaction.memo
      };
    }

    // 9. All checks passed
    return {
      valid: true,
      transactionHash,
      amount: actualAmount.toString(),
      asset: actualAsset,
      from: paymentOp.from,
      to: paymentOp.to,
      ledger: transaction.ledger_attr,
      timestamp: transaction.created_at
    };

  } catch (error) {
    if (error.response?.status === 404) {
      return {
        valid: false,
        error: 'TRANSACTION_NOT_FOUND',
        details: 'Transaction hash not found on Stellar network'
      };
    }

    throw error;
  }
}

Double-Spend Prevention

typescript

// Prevent the same transaction from being used multiple times
async function preventDoubleSpend(transactionHash: string): Promise<boolean> {
  // Check if transaction already used
  const existing = await prisma.payment.findUnique({
    where: { transactionHash }
  });

  if (existing) {
    logger.warn('Double-spend attempt detected', {
      transactionHash,
      existingPaymentId: existing.id,
      existingInvoiceId: existing.invoiceId
    });
    return false;
  }

  // Use database unique constraint as final guard
  // If race condition occurs, constraint will prevent duplicate
  return true;
}

// Database schema with unique constraint
// schema.prisma
model Payment {
  id              String   @id @default(cuid())
  transactionHash String   @unique  // Prevents double-spend at DB level
  invoiceId       String
  amount          String
  asset           String
  from            String
  to              String
  status          PaymentStatus
  createdAt       DateTime @default(now())

  invoice Invoice @relation(fields: [invoiceId], references: [id])

  @@index([invoiceId])
  @@index([status])
}

Network Validation

typescript

// Ensure payment is on correct Stellar network
async function validateNetwork(transaction: any): Promise<boolean> {
  const networkPassphrase = process.env.STELLAR_NETWORK === 'testnet'
    ? Networks.TESTNET
    : Networks.PUBLIC;

  // Verify transaction network matches expected network
  const txNetwork = transaction.network_passphrase;

  if (txNetwork !== networkPassphrase) {
    logger.error('Network mismatch detected', {
      expected: networkPassphrase,
      actual: txNetwork,
      transactionHash: transaction.hash
    });
    return false;
  }

  return true;
}

API Security

Input Validation

All API inputs are validated using Zod schemas:

typescript

import { z } from 'zod';

// Invoice creation schema
const createInvoiceSchema = z.object({
  amount: z.string()
    .regex(/^\d+(\.\d{1,7})?$/, 'Invalid amount format')
    .refine(val => {
      const num = parseFloat(val);
      return num > 0 && num <= 1000000;
    }, 'Amount must be between 0 and 1,000,000'),

  asset: z.enum(['XLM', 'USDC', 'EURC'])
    .default('XLM'),

  description: z.string()
    .min(1, 'Description required')
    .max(500, 'Description too long')
    .trim(),

  clientName: z.string()
    .max(100, 'Client name too long')
    .optional(),

  clientEmail: z.string()
    .email('Invalid email format')
    .optional(),

  expiresIn: z.number()
    .int()
    .min(300, 'Minimum 5 minutes')
    .max(86400 * 30, 'Maximum 30 days')
    .default(3600),

  metadata: z.record(z.string(), z.any())
    .optional()
    .refine(val => {
      if (!val) return true;
      return JSON.stringify(val).length <= 2000;
    }, 'Metadata too large')
});

// Validation middleware
function validateRequest<T>(schema: z.ZodSchema<T>) {
  return async (req: Request, res: Response, next: NextFunction) => {
    try {
      req.body = await schema.parseAsync(req.body);
      next();
    } catch (error) {
      if (error instanceof z.ZodError) {
        return res.status(400).json({
          error: 'VALIDATION_ERROR',
          details: error.errors.map(e => ({
            field: e.path.join('.'),
            message: e.message
          }))
        });
      }
      next(error);
    }
  };
}

// Usage
router.post('/invoices',
  authenticate,
  validateRequest(createInvoiceSchema),
  invoiceController.create
);

SQL Injection Prevention

Using Prisma ORM with parameterized queries:

typescript

// Safe - Prisma automatically parameterizes
const invoices = await prisma.invoice.findMany({
  where: {
    merchantId: userId,
    status: 'PENDING',
    amount: { gte: minAmount }
  }
});

// Safe - Using raw queries with parameterization
const result = await prisma.$queryRaw`
  SELECT * FROM invoices
  WHERE merchant_id = ${userId}
  AND status = ${status}
  AND amount >= ${minAmount}
`;

// NEVER do this (vulnerable to SQL injection)
// const query = `SELECT * FROM invoices WHERE merchant_id = '${userId}'`;

XSS Prevention

typescript

// Content Security Policy headers
app.use(helmet({
  contentSecurityPolicy: {
    directives: {
      defaultSrc: ["'self'"],
      scriptSrc: ["'self'", "'unsafe-inline'"],
      styleSrc: ["'self'", "'unsafe-inline'"],
      imgSrc: ["'self'", 'data:', 'https:'],
      connectSrc: ["'self'", 'https://horizon.stellar.org'],
      fontSrc: ["'self'"],
      objectSrc: ["'none'"],
      mediaSrc: ["'self'"],
      frameSrc: ["'none'"]
    }
  },
  hsts: {
    maxAge: 31536000,
    includeSubDomains: true,
    preload: true
  }
}));

// Sanitize output in responses
import DOMPurify from 'isomorphic-dompurify';

function sanitizeOutput(data: any): any {
  if (typeof data === 'string') {
    return DOMPurify.sanitize(data);
  }
  if (Array.isArray(data)) {
    return data.map(sanitizeOutput);
  }
  if (typeof data === 'object' && data !== null) {
    const sanitized: any = {};
    for (const [key, value] of Object.entries(data)) {
      sanitized[key] = sanitizeOutput(value);
    }
    return sanitized;
  }
  return data;
}

CSRF Protection

typescript

import csrf from 'csurf';

// CSRF protection for state-changing operations
const csrfProtection = csrf({
  cookie: {
    httpOnly: true,
    secure: process.env.NODE_ENV === 'production',
    sameSite: 'strict'
  }
});

// Apply to state-changing routes
router.post('/invoices', csrfProtection, createInvoice);
router.patch('/invoices/:id', csrfProtection, updateInvoice);
router.delete('/invoices/:id', csrfProtection, deleteInvoice);

// Endpoint to get CSRF token
router.get('/csrf-token', csrfProtection, (req, res) => {
  res.json({ csrfToken: req.csrfToken() });
});

Webhook Security

Signature Verification

typescript

// Generate webhook signature
function generateSignature(payload: string, secret: string): string {
  return crypto
    .createHmac('sha256', secret)
    .update(payload)
    .digest('hex');
}

// Verify webhook signature
function verifyWebhookSignature(
  payload: string,
  signature: string,
  secret: string
): boolean {
  const expectedSignature = generateSignature(payload, secret);

  // Timing-safe comparison to prevent timing attacks
  return crypto.timingSafeEqual(
    Buffer.from(signature),
    Buffer.from(expectedSignature)
  );
}

// Webhook handler with verification
router.post('/webhooks/link2pay',
  express.raw({ type: 'application/json' }),
  async (req, res) => {
    const signature = req.headers['x-link2pay-signature'] as string;
    const timestamp = req.headers['x-link2pay-timestamp'] as string;

    // 1. Verify signature exists
    if (!signature || !timestamp) {
      return res.status(401).json({
        error: 'Missing signature or timestamp'
      });
    }

    // 2. Verify timestamp is recent (prevent replay attacks)
    const requestTime = parseInt(timestamp, 10);
    const currentTime = Math.floor(Date.now() / 1000);
    const timeDiff = Math.abs(currentTime - requestTime);

    if (timeDiff > 300) { // 5 minutes tolerance
      return res.status(401).json({
        error: 'Request timestamp too old'
      });
    }

    // 3. Verify signature
    const payload = req.body.toString('utf-8');
    const isValid = verifyWebhookSignature(
      payload,
      signature,
      process.env.WEBHOOK_SECRET!
    );

    if (!isValid) {
      logger.warn('Invalid webhook signature', {
        ip: req.ip,
        signature
      });
      return res.status(401).json({ error: 'Invalid signature' });
    }

    // 4. Respond immediately
    res.json({ received: true });

    // 5. Process asynchronously
    const event = JSON.parse(payload);
    await processWebhookEvent(event);
  }
);

Idempotency

typescript

// Prevent duplicate webhook processing
async function processWebhookEvent(event: WebhookEvent) {
  const eventId = event.id;

  // Check if already processed
  const existing = await redis.get(`webhook:${eventId}`);
  if (existing) {
    logger.info('Duplicate webhook event ignored', { eventId });
    return;
  }

  // Mark as processing
  await redis.setex(
    `webhook:${eventId}`,
    86400 * 7, // Keep for 7 days
    JSON.stringify({ processedAt: new Date().toISOString() })
  );

  // Process event
  try {
    await handleEvent(event);
  } catch (error) {
    logger.error('Webhook processing failed', { eventId, error });
    // Don't throw - event is marked as processed to prevent retries
  }
}

Transport Security

TLS/HTTPS

All production deployments must use HTTPS:

typescript

// Enforce HTTPS in production
if (process.env.NODE_ENV === 'production') {
  app.use((req, res, next) => {
    if (req.header('x-forwarded-proto') !== 'https') {
      return res.redirect(`https://${req.header('host')}${req.url}`);
    }
    next();
  });
}

// HSTS header
app.use(helmet.hsts({
  maxAge: 31536000, // 1 year
  includeSubDomains: true,
  preload: true
}));

CORS Configuration

typescript

import cors from 'cors';

// Strict CORS policy
const corsOptions = {
  origin: (origin: string | undefined, callback: Function) => {
    const allowedOrigins = process.env.ALLOWED_ORIGINS?.split(',') || [];

    // Allow requests with no origin (mobile apps, curl)
    if (!origin) return callback(null, true);

    if (allowedOrigins.includes(origin)) {
      callback(null, true);
    } else {
      callback(new Error('Not allowed by CORS'));
    }
  },
  credentials: true,
  methods: ['GET', 'POST', 'PATCH', 'DELETE'],
  allowedHeaders: ['Content-Type', 'Authorization'],
  exposedHeaders: ['X-Total-Count'],
  maxAge: 600 // 10 minutes
};

app.use(cors(corsOptions));

Data Security

Sensitive Data Handling

typescript

// Never log sensitive data
logger.info('User authenticated', {
  userId: user.id,
  // DON'T log: walletAddress, signature, tokens
});

// Mask sensitive data in responses
function maskWalletAddress(address: string): string {
  return `${address.slice(0, 4)}...${address.slice(-4)}`;
}

// Redact sensitive fields from logs
const logRedaction = {
  paths: [
    'password',
    'token',
    'apiKey',
    'secret',
    'signature',
    'authorization'
  ],
  censor: '[REDACTED]'
};

Data Encryption at Rest

typescript

// Encrypt sensitive metadata before storage
import { createCipheriv, createDecipheriv, randomBytes } from 'crypto';

const ENCRYPTION_KEY = Buffer.from(process.env.ENCRYPTION_KEY!, 'hex');
const ALGORITHM = 'aes-256-gcm';

function encrypt(text: string): string {
  const iv = randomBytes(16);
  const cipher = createCipheriv(ALGORITHM, ENCRYPTION_KEY, iv);

  let encrypted = cipher.update(text, 'utf8', 'hex');
  encrypted += cipher.final('hex');

  const authTag = cipher.getAuthTag();

  return `${iv.toString('hex')}:${authTag.toString('hex')}:${encrypted}`;
}

function decrypt(encrypted: string): string {
  const [ivHex, authTagHex, encryptedText] = encrypted.split(':');

  const iv = Buffer.from(ivHex, 'hex');
  const authTag = Buffer.from(authTagHex, 'hex');
  const decipher = createDecipheriv(ALGORITHM, ENCRYPTION_KEY, iv);

  decipher.setAuthTag(authTag);

  let decrypted = decipher.update(encryptedText, 'hex', 'utf8');
  decrypted += decipher.final('utf8');

  return decrypted;
}

// Usage in database
await prisma.invoice.create({
  data: {
    amount: '100.00',
    metadata: encrypt(JSON.stringify(sensitiveMetadata))
  }
});

Production Best Practices

Environment Variables

bash

# .env.example - never commit actual .env file
NODE_ENV=production
DATABASE_URL=postgresql://user:pass@localhost:5432/link2pay
REDIS_URL=redis://localhost:6379

# JWT configuration
JWT_SECRET=<256-bit random hex>  # openssl rand -hex 32
JWT_EXPIRY=3600

# Encryption
ENCRYPTION_KEY=<256-bit random hex>  # openssl rand -hex 32

# Webhook security
WEBHOOK_SECRET=<256-bit random hex>

# Stellar configuration
STELLAR_NETWORK=public
HORIZON_URL=https://horizon.stellar.org

# API keys (rotate regularly)
API_KEY_SECRET=<256-bit random hex>

# CORS
ALLOWED_ORIGINS=https://app.link2pay.dev,https://www.link2pay.dev

# Rate limiting
RATE_LIMIT_WINDOW_MS=900000  # 15 minutes
RATE_LIMIT_MAX_REQUESTS=100

Security Headers

typescript

import helmet from 'helmet';

app.use(helmet({
  contentSecurityPolicy: true,
  crossOriginEmbedderPolicy: true,
  crossOriginOpenerPolicy: true,
  crossOriginResourcePolicy: true,
  dnsPrefetchControl: true,
  frameguard: { action: 'deny' },
  hidePoweredBy: true,
  hsts: {
    maxAge: 31536000,
    includeSubDomains: true,
    preload: true
  },
  ieNoOpen: true,
  noSniff: true,
  originAgentCluster: true,
  permittedCrossDomainPolicies: false,
  referrerPolicy: { policy: 'strict-origin-when-cross-origin' },
  xssFilter: true
}));

Logging and Monitoring

typescript

import winston from 'winston';

const logger = winston.createLogger({
  level: process.env.LOG_LEVEL || 'info',
  format: winston.format.combine(
    winston.format.timestamp(),
    winston.format.errors({ stack: true }),
    winston.format.json()
  ),
  defaultMeta: { service: 'link2pay-api' },
  transports: [
    new winston.transports.File({
      filename: 'logs/error.log',
      level: 'error'
    }),
    new winston.transports.File({
      filename: 'logs/combined.log'
    })
  ]
});

// Security event logging
function logSecurityEvent(event: string, details: any) {
  logger.warn('Security event', {
    event,
    ...details,
    timestamp: new Date().toISOString(),
    ip: details.ip,
    userAgent: details.userAgent
  });
}

// Examples
logSecurityEvent('AUTHENTICATION_FAILED', {
  walletAddress,
  reason: 'Invalid signature',
  ip: req.ip,
  userAgent: req.headers['user-agent']
});

logSecurityEvent('RATE_LIMIT_EXCEEDED', {
  endpoint: req.path,
  ip: req.ip,
  limit: rateLimitConfig.max
});

Incident Response

Security Incident Checklist:

Detection
- Monitor logs for suspicious activity
- Set up alerts for security events
- Review Stellar transactions regularly
Containment
- Revoke compromised API keys immediately
- Rotate affected secrets
- Block malicious IPs
- Disable compromised webhooks
Investigation
- Analyze logs and transaction history
- Identify scope of compromise
- Document timeline of events
Recovery
- Deploy fixes for vulnerabilities
- Restore from backups if needed
- Verify system integrity
Post-Incident
- Notify affected users
- Update security measures
- Document lessons learned

Security Checklist

Pre-Launch Security Review

[ ] All API endpoints require authentication
[ ] Input validation on all user inputs
[ ] SQL injection prevention (parameterized queries)
[ ] XSS prevention (CSP headers, output sanitization)
[ ] CSRF protection on state-changing operations
[ ] Rate limiting on all endpoints
[ ] HTTPS enforced in production
[ ] Security headers configured (Helmet)
[ ] CORS properly configured
[ ] Webhook signature verification
[ ] Payment verification on Stellar network
[ ] Double-spend prevention
[ ] Sensitive data encrypted at rest
[ ] Secrets in environment variables (not code)
[ ] Error messages don't leak sensitive info
[ ] Logging doesn't capture sensitive data
[ ] Database backups encrypted
[ ] Incident response plan documented
[ ] Security monitoring and alerts configured
[ ] Dependencies regularly updated
[ ] Third-party code audited

Regular Security Maintenance

Weekly:

Review security logs
Check for suspicious transactions
Monitor rate limit violations

Monthly:

Update dependencies
Rotate API keys
Review access controls
Test backup restoration

Quarterly:

Security audit
Penetration testing
Review and update security policies
Staff security training

Security Model ​

Overview ​

Security Principles ​

Threat Model ​

Assets to Protect ​

Threat Actors ​

Attack Vectors ​

Authentication Security ​

Wallet-Based Authentication ​

Security Features ​

Payment Security ​

Payment Verification ​

Double-Spend Prevention ​

Network Validation ​

API Security ​

Input Validation ​

SQL Injection Prevention ​

XSS Prevention ​

CSRF Protection ​

Webhook Security ​

Signature Verification ​

Idempotency ​

Transport Security ​

TLS/HTTPS ​

CORS Configuration ​

Data Security ​

Sensitive Data Handling ​

Data Encryption at Rest ​

Production Best Practices ​

Environment Variables ​

Security Headers ​

Logging and Monitoring ​

Incident Response ​

Security Checklist ​

Pre-Launch Security Review ​

Regular Security Maintenance ​

Additional Resources ​

Security Model

Overview

Security Principles

Threat Model

Assets to Protect

Threat Actors

Attack Vectors

Authentication Security

Wallet-Based Authentication

Security Features

Payment Security

Payment Verification

Double-Spend Prevention

Network Validation

API Security

Input Validation

SQL Injection Prevention

XSS Prevention

CSRF Protection

Webhook Security

Signature Verification

Idempotency

Transport Security

TLS/HTTPS

CORS Configuration

Data Security

Sensitive Data Handling

Data Encryption at Rest

Production Best Practices

Environment Variables

Security Headers

Logging and Monitoring

Incident Response

Security Checklist

Pre-Launch Security Review

Regular Security Maintenance

Additional Resources