Finance glossary
Strong Customer Authentication — SCA
Also known as: SCA
In simple terms
Strong Customer Authentication is the extra security check — like a code from your bank or a fingerprint — used to confirm it is really you making an online payment.
On this page
What does strong customer authentication mean?
Strong Customer Authentication (SCA) is a security requirement for many electronic payments, especially online. It asks you to verify yourself using at least two independent factors — something you know, have, or are.
It is why online card payments often trigger a bank app approval or a one-time code.
How SCA works
When you pay online, the payment may be routed for authentication — for example approving it in your banking app, entering a texted code, or using a fingerprint. Two of the three factor types must usually be used.
Some low-value or recurring payments are exempt, which is why not every transaction asks for it.
How could this affect me?
SCA adds a small step but significantly reduces online card fraud. Keeping your phone number and banking app up to date ensures the checks reach you smoothly.
Fraudsters may try to trick you into approving or reading out these codes — never share a one-time code with anyone who contacts you.
Things to watch out for
- Never share a one-time code with anyone who calls or messages you.
- Keep your phone number and banking app up to date so checks reach you.
- A genuine bank will not ask you to approve a payment you did not make.
Know your rights
- Strong Customer Authentication is required for many electronic payments under the Payment Services Regulations 2017.
- Unauthorised payments remain generally refundable under those regulations; complaints go to the Financial Ombudsman Service.
General information, not personal advice
Consumer Credit is an independent information service. We do not provide regulated financial advice or sell financial products. For advice on your own situation, speak to an appropriately authorised firm or a free service such as MoneyHelper. About Consumer Credit.
Sources
We checked this page against these official and authoritative sources.
- legislation.gov.uk, The Payment Services Regulations 2017 (opens in a new tab). Accessed 22 Aug 2026.