Blog | G5 Cyber Security

User Data Encryption: Best Practices

G5 Cyber Security

TL;DR

Encrypt user data at rest and in transit using strong algorithms (AES-256, TLS 1.3+). Implement key management best practices – don’t store keys with the data! Use a combination of techniques like field-level encryption, envelope encryption, and secure enclaves for enhanced security. Regularly audit your systems and follow compliance standards.

1. Understand Your Data

  1. Identify Sensitive Data: What information *needs* encrypting? This includes Personally Identifiable Information (PII) like names, addresses, credit card details, health records, etc.
  2. Data Classification: Categorise data based on sensitivity level. Higher sensitivity requires stronger encryption and more robust key management.

2. Encryption at Rest

This means encrypting data when it’s stored – in databases, filesystems, backups.

  1. Database Encryption: Most modern databases offer Transparent Data Encryption (TDE). This encrypts the entire database file.
    • Example (PostgreSQL with pgcrypto):
    CREATE EXTENSION pgcrypto;
UPDATE users SET password = pgp_sym_encrypt(password, 'your_encryption_key');
  2. Filesystem Encryption: Use tools like LUKS (Linux), BitLocker (Windows), or FileVault (macOS) to encrypt entire disks or partitions.
  3. Field-Level Encryption: Encrypt specific columns/fields within a database, offering more granular control.
    • This is useful when you only need to protect certain data points.

3. Encryption in Transit

Protecting data as it moves between systems.

  1. HTTPS/TLS: Use HTTPS (HTTP Secure) with TLS 1.3 or higher for all web traffic. This encrypts communication between the user’s browser and your server.
    • Ensure your SSL/TLS certificates are valid and up-to-date.
  2. VPNs: Use Virtual Private Networks (VPNs) for secure connections when accessing data remotely.
  3. SSH: Secure Shell (SSH) provides encrypted communication for remote server access.

4. Key Management

This is the *most* critical part. Poor key management renders encryption useless.

  1. Never Store Keys with Data: This is a fundamental rule! If an attacker gains access to your data storage, they’ll also have the keys.
  2. Key Rotation: Regularly change your encryption keys (e.g., every 90-180 days).
  3. Hardware Security Modules (HSMs): Use HSMs to securely store and manage encryption keys in dedicated hardware.
    • HSMs provide a tamper-resistant environment for key operations.
  4. Key Management Systems (KMS): Cloud providers offer KMS services (e.g., AWS KMS, Azure Key Vault) to manage keys securely.
    • These systems often integrate with other cloud services.
  5. Envelope Encryption: Encrypt your data key with a master key stored in an HSM or KMS. This allows you to encrypt large amounts of data without directly handling the master key.
    • Example (simplified):
    # Generate a data key
data_key = generate_random_key()

# Encrypt your data with the data key
encrypted_data = encrypt(data, data_key)

# Encrypt the data key with the master key
enrypted_data_key = encrypt(data_key, master_key)

5. Secure Enclaves

Use secure enclaves (e.g., Intel SGX, ARM TrustZone) to perform sensitive operations in a protected environment.

  1. Confidential Computing: Enclaves isolate code and data from the rest of the system, even if the operating system is compromised.
    • Useful for decrypting data within a trusted execution environment.

6. Auditing & Compliance

  1. Regular Security Audits: Conduct regular audits to identify vulnerabilities and ensure your encryption systems are working correctly.
  2. Compliance Standards: Follow relevant compliance standards (e.g., GDPR, HIPAA, PCI DSS) based on the type of data you’re handling.
    • These standards often have specific requirements for data encryption.
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