# MASK

```
MASK(strExpr)
```

Alias for ANONYMIZE.

Available in:

| Processors | SQL Studio |
| ---------- | ---------- |
| ✓          | ✓          |

*Sample code:*

```sql
USE `kafka`;
SELECT 
  MASK(first_name) AS first_name_hidden,
  first_name  
FROM users-events
LIMIT 1;
```

*Output:*

```json
{
  "value": {
    "first_name_hidden": "*******",
    "first_name": "Charles"
  }
}
```