> ## Documentation Index
> Fetch the complete documentation index at: https://docs.datafog.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Privacy transformations

> Choose between redaction, masking, removal, pseudonymization, and tokenization.

DataFog Core exposes concrete transformation strategies rather than claiming
that every output is anonymous.

| Strategy       | Output                           | Reversible | Provider required | Browser/WASM |
| -------------- | -------------------------------- | ---------- | ----------------- | ------------ |
| `redact`       | `[ENTITY_TYPE]`                  | No         | No                | Supported    |
| `mask`         | Configured mask characters       | No         | No                | Supported    |
| `remove`       | Empty replacement                | No         | No                | Supported    |
| `pseudonymize` | Keyed HMAC-SHA-256 pseudonym     | No         | Key provider      | Unsupported  |
| `tokenize`     | Opaque `DFTOKENv1(...)` envelope | Yes        | Token provider    | Unsupported  |

## Redact

Redaction replaces each selected finding with an unnumbered entity placeholder.

```json theme={null}
{ "default": { "strategy": "redact" } }
```

`jane@example.com` becomes `[EMAIL]`.

## Mask

Masking replaces every non-revealed Unicode code point. The default character
is `*`. A custom character must be exactly one non-whitespace, non-control
Unicode code point.

```json theme={null}
{
  "default": {
    "strategy": "mask",
    "character": "•",
    "reveal": { "direction": "last", "count": 4 }
  }
}
```

## Remove

Removal deletes only the exact finding span. It does not normalize adjacent
whitespace.

```json theme={null}
{ "default": { "strategy": "remove" } }
```

## Pseudonymize

Pseudonymization computes deterministic HMAC-SHA-256 over the exact UTF-8
matched value using a provider-resolved 32-byte key. Use it when stable equality
under an intentionally scoped secret key is required.

See [Pseudonymization](/guides/pseudonymization).

## Tokenize

Tokenization asks an application-owned provider to issue opaque token payloads.
The resulting envelope can later be restored under the same exact request
scope.

See [Tokenization and restoration](/guides/tokenization-and-restoration).

## Transformation records

Each applied replacement produces a record with:

* source ranges and detector provenance;
* the strategy and exact replacement;
* output ranges that select the replacement;
* resolved key metadata for pseudonymization; or
* resolved token metadata for tokenization.

The record does not include `matched_text` or a plaintext-to-token mapping.