What is a card number?¶

A card number is the identifier associated with a payment card account and used to route card transactions.

Avoid this assumption: The visible card number uniquely identifies one physical card and one user.

The number usually identifies the card issuer, account range and individual card account.

It may appear in full within secure provider systems and in masked form on statements, receipts and applications.

The same underlying account may have several physical cards, replacement cards or digital tokens.

A mobile wallet may use a tokenised number rather than the actual card number during payment.

A replacement card may have a new number while remaining linked to the same customer account.

Conversely, several users may hold additional cards linked to one account.

Preserve the number exactly as displayed, including which digits are masked and which are visible.

Do not attempt to infer the missing digits from partial information.

Use the number with transaction references, dates, amounts, merchant details and issuer records to identify the relevant account and payment route.

Where tokenisation is involved, ask the issuer or wallet provider to link the token to the underlying card account.

A card number does not prove possession of the physical card. Card details can be stored, copied, intercepted or used online.

Nor does it prove the identity of the person making the payment.

When reporting, distinguish between the physical card, card account and token used in the transaction.

Operational takeaway¶

Use the card number to identify the card account and issuer, while treating the physical card, digital token and actual user as separate evidential issues.