evernote-security-basics

Evernote Security Basics

Overview

Security best practices for Evernote API integrations, covering credential management, OAuth hardening, token storage, data protection, and secure logging patterns.

Prerequisites

• Evernote SDK setup
• Understanding of OAuth 1.0a
• Basic cryptography concepts (AES encryption, hashing)

Instructions

Step 1: Credential Management

Store consumerKey, consumerSecret, and access tokens in environment variables or a secrets manager (AWS Secrets Manager, GCP Secret Manager, HashiCorp Vault). Never commit credentials to source control. Add .env to .gitignore.

// Load from environment, fail fast if missing
const requiredVars = ['EVERNOTE_CONSUMER_KEY', 'EVERNOTE_CONSUMER_SECRET'];
for (const v of requiredVars) {
  if (!process.env[v]) throw new Error(`Missing required env var: ${v}`);
}

Step 2: Secure OAuth Flow

Add CSRF protection with a state parameter stored in the session. Validate the callback URL matches your registered domain. Use HTTPS-only for all OAuth endpoints. Set secure cookie flags for session tokens.

// Generate CSRF token for OAuth state
const csrfToken = crypto.randomBytes(32).toString('hex');
req.session.oauthCsrf = csrfToken;

// Verify on callback
if (req.query.state !== req.session.oauthCsrf) {
  return res.status(403).send('CSRF validation failed');
}

Step 3: Encrypted Token Storage

Encrypt access tokens at rest using AES-256-GCM before storing in your database. Decrypt only when making API calls. Store the encryption key separately from the database.

Step 4: Input Validation

Sanitize all user input before embedding in ENML. Validate note titles (max 255 chars), tag names (max 100 chars, no commas), and notebook names (max 100 chars). Strip forbidden HTML elements and attributes.

Step 5: Secure Logging

Redact access tokens, consumer secrets, and user email addresses from log output. Log only the first 8 characters of tokens for debugging correlation.

function redactToken(token) {
  if (!token || token.length < 12) return '***';
  return token.slice(0, 8) + '...[REDACTED]';
}

Step 6: Token Lifecycle Management

Track token expiration (edam_expires), implement proactive refresh before expiry, and handle AUTH_EXPIRED errors gracefully. Tokens default to 1-year validity but users can set shorter durations.

For the complete security implementation including encrypted storage, CSRF-protected OAuth, input validation, and audit logging, see Implementation Guide.

Output

• Environment-based credential management with validation
• CSRF-protected OAuth 1.0a flow
• AES-256-GCM encrypted token storage
• Input sanitization for ENML content and metadata
• Redacted logging utility
• Token expiration tracking and refresh

Error Handling

Error	Cause	Solution
INVALID_AUTH	Token revoked or invalid	Re-authenticate via OAuth; check token not corrupted during encryption
AUTH_EXPIRED	Token past expiration date	Implement proactive refresh before edam_expires
PERMISSION_DENIED	API key lacks required scope	Request appropriate permissions from Evernote
CSRF mismatch	Session expired or attack attempt	Regenerate CSRF token and restart OAuth flow

Resources

• OAuth Documentation
• API Key Permissions
• OWASP Security Guidelines
• Node.js Crypto (AES)

Next Steps

For production deployment checklist, see evernote-prod-checklist.

Examples

Secure credential setup: Store credentials in AWS Secrets Manager, load at startup, validate all required values are present, and fail fast on missing configuration.

Token rotation: Monitor edam_expires for all stored tokens, send re-authentication emails 30 days before expiry, and gracefully degrade to read-only mode when tokens expire.