---
Source: https://docs.microblink.com/blinkcard/anonymization
Title: Mask and anonymize card data
Description: Anonymize the card number, CVV, IBAN, and cardholder name in BlinkCard results and images for PCI DSS compliance
---

# Mask and anonymize card data

Handling images and data of payment cards has implications for PCI DSS compliance.
BlinkCard can anonymize sensitive fields so they never appear in the data or images it returns.

## Anonymization modes

Each field is anonymized according to an anonymization mode.

- **type**: string
- `"none"`: no anonymization
- `"image-only"`: the field is covered with a black box in the returned card image, but stays in the result data
- `"result-fields-only"`: the field is removed from the result data, but stays visible in the image
- `"full-result"`: the field is removed from both the data and the image

The mode is the same concept on every platform, but the names differ.

- Web: `AnonymizationMode` string values `"none"`, `"image-only"`, `"result-fields-only"`, `"full-result"`.
- Android: `AnonymizationMode` enum values `None`, `ImageOnly`, `ResultFieldsOnly`, `FullResult`.
- iOS: `RedactionMode` enum cases `.none`, `.imageOnly`, `.resultFieldsOnly`, `.fullResult`.

## Anonymize fields

Anonymization is configured on the scanning settings and passed when you start the session.

<Tabs queryString="platform">
  <TabItem value="web" label="Web (JS)" default>

Configure anonymization through `scanningSettings.anonymizationSettings` and pass it when you create the scanner.

```ts
const blinkCard = await createBlinkCard({
  licenseKey: "your-license-key",
  scanningSettings: {
    anonymizationSettings: {
      cvvAnonymizationMode: "full-result",
      ibanAnonymizationMode: "full-result",
      cardholderNameAnonymizationMode: "result-fields-only",
    },
  },
});
```

  </TabItem>
  <TabItem value="android" label="Android (Kotlin)">

Configure `AnonymizationSettings` on `ScanningSettings`, wrap it in a `BlinkCardSessionSettings`, and pass that to `BlinkCardCameraScanningScreen` through its `sessionSettings` parameter.

```kotlin
val sessionSettings = BlinkCardSessionSettings(
    scanningSettings = ScanningSettings(
        anonymizationSettings = AnonymizationSettings(
            cvvAnonymizationMode = AnonymizationMode.FullResult,
            ibanAnonymizationMode = AnonymizationMode.FullResult,
            cardholderNameAnonymizationMode = AnonymizationMode.ResultFieldsOnly,
        ),
    ),
)

BlinkCardCameraScanningScreen(
    sessionSettings = sessionSettings,
    // other parameters
)
```

  </TabItem>
  <TabItem value="ios" label="iOS (Swift)">

On iOS the equivalent settings live on `RedactionSettings`.
Set them on `scanningSettings.redactionSettings` and pass the session settings to `BlinkCardAnalyzer(sdk:blinkCardSessionSettings:)`.

```swift
var sessionSettings = BlinkCardSessionSettings()
sessionSettings.scanningSettings.redactionSettings = RedactionSettings(
    cvvRedactionMode: .fullResult,
    ibanRedactionMode: .fullResult,
    cardholderNameRedactionMode: .resultFieldsOnly
)

let analyzer = try await BlinkCardAnalyzer(
    sdk: blinkCardSdk,
    blinkCardSessionSettings: sessionSettings
)
```

  </TabItem>
</Tabs>

The available per-field modes are:

- `cvvAnonymizationMode` (iOS: `cvvRedactionMode`)
- `ibanAnonymizationMode` (iOS: `ibanRedactionMode`)
- `cardholderNameAnonymizationMode` (iOS: `cardholderNameRedactionMode`)
- `cardNumberPrefixAnonymizationMode` (iOS: `cardNumberPrefixRedactionMode`)

## Partially mask the card number

The card number has its own settings object so you can keep part of it visible, for example the last four digits for display.
The object takes a mode plus the number of digits to leave visible at each end.

<Tabs queryString="platform">
  <TabItem value="web" label="Web (JS)" default>

`cardNumberAnonymizationSettings` takes a `mode` plus `prefixDigitsVisible` and `suffixDigitsVisible`.

```ts
const blinkCard = await createBlinkCard({
  licenseKey: "your-license-key",
  scanningSettings: {
    anonymizationSettings: {
      cardNumberAnonymizationSettings: {
        mode: "full-result",
        prefixDigitsVisible: 0,
        suffixDigitsVisible: 4,
      },
    },
  },
});
```

  </TabItem>
  <TabItem value="android" label="Android (Kotlin)">

`CardNumberAnonymizationSettings` takes an `anonymizationMode` plus `prefixDigitsVisible` and `suffixDigitsVisible`.

```kotlin
val sessionSettings = BlinkCardSessionSettings(
    scanningSettings = ScanningSettings(
        anonymizationSettings = AnonymizationSettings(
            cardNumberAnonymizationSettings = CardNumberAnonymizationSettings(
                anonymizationMode = AnonymizationMode.FullResult,
                prefixDigitsVisible = 0U,
                suffixDigitsVisible = 4U,
            ),
        ),
    ),
)
```

  </TabItem>
  <TabItem value="ios" label="iOS (Swift)">

`CardNumberRedactionSettings` takes a `mode` plus `prefixDigitsVisible` and `suffixDigitsVisible`.

```swift
var sessionSettings = BlinkCardSessionSettings()
sessionSettings.scanningSettings.redactionSettings = RedactionSettings(
    cardNumberRedactionSettings: CardNumberRedactionSettings(
        mode: .fullResult,
        prefixDigitsVisible: 0,
        suffixDigitsVisible: 4
    )
)
```

  </TabItem>
</Tabs>

With the settings above, the card number is masked in both the data and the image, leaving only the last four digits visible.

## Mask the card image

Set a field's mode to `"image-only"` or `"full-result"` to cover that field with a black box in the returned card image.
This applies to whichever fields you configure, so to redact every sensitive field from the image, set each field's mode accordingly.

If you don't need the card image at all, disable it entirely instead through `croppedImageSettings.returnCardImage`.

## Related articles

- [Extract specific fields](./extract-fields.md)
- [Detect fraud and liveness](./liveness.md)


Last updated on Jun 18, 2026