ACTL

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Building a service securely

If you're building an app, website or online service, security is cheapest when you design it in from the start. These are practical habits for the build and run phases — not a compliance checklist.

Accounts & access

  • Offer or require MFA on customer sign-in, especially for accounts holding personal or payment data.
  • Apply least privilege — give each user and service account only the access it needs.
  • Never hard-code credentials or API keys in your code or repository; use a secrets manager.

Data handling

  • Collect the minimum personal information you actually need (data minimisation — APP 3).
  • Hash passwords with a strong, salted algorithm — never store them in plain text.
  • Encrypt sensitive data in transit (HTTPS/TLS) and at rest.
  • Delete or de-identify personal information you no longer need (APP 11).

Environments & operations

  • Separate development, testing and production environments; never use real customer data in dev/test.
  • Keep dependencies and frameworks patched; monitor for known vulnerabilities.
  • Keep audit logs of access and changes — and protect the logs themselves.
  • Back up data and configuration, store a copy offline, and test restores regularly.

Before you launch

Before you go live: MFA on, secrets out of code, real data out of test, backups tested, and a plan for what to do if there's a breach (see Privacy Obligations).

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Official sources

Targeted by a business scam?

Invoice fraud, Business Email Compromise (BEC) and payment redirection — see how to respond and report.

Go to Business Scams

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