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

# Encrypting Data

> How to encrypt data using Qanapi Smart Data Proxies

# Encrypting Data with Smart Data Proxies

This guide demonstrates how to use the Qanapi Smart Data Proxy to encrypt sensitive data within JSON payloads.

## Encryption Process Overview

When you encrypt data with the Smart Data Proxy:

1. Your application sends a JSON payload to your project's proxy endpoint
2. You specify which fields to encrypt using the `X-Qanapi-Fields` header
3. Qanapi encrypts only those specified fields, leaving the rest untouched
4. The encrypted data is returned in the same structure, with encrypted values replacing the original sensitive data

## Basic Encryption Request

Here's a basic example of how to encrypt data using the Smart Data Proxy:

```bash theme={null}
curl --location 'https://your-tenant.qanapi.cloud/proxy/your-project-id' \
--header 'X-Qanapi-Authorization: your_api_key' \
--header 'X-Qanapi-Mode: encrypt' \
--header 'X-Qanapi-Fields: title,body' \
--header 'Content-Type: application/json' \
--data '{
    "userId": 1,
    "id": 1,
    "title": "Title text to encrypt",
    "body": "Body text to encrypt"
}'
```

## Understanding the Headers

For encryption requests, you need to include these headers:

| Header                   | Value              | Description                                    |
| ------------------------ | ------------------ | ---------------------------------------------- |
| `X-Qanapi-Authorization` | `your_api_key`     | Your API key for authentication                |
| `X-Qanapi-Mode`          | `encrypt`          | Specifies that you want to encrypt data        |
| `X-Qanapi-Fields`        | `title,body`       | Comma-separated list of field names to encrypt |
| `Content-Type`           | `application/json` | Specifies that the payload is JSON             |

## Optional Headers for Encryption

You can also include these optional headers:

| Header                 | Example Value             | Description                             |
| ---------------------- | ------------------------- | --------------------------------------- |
| `X-Qanapi-Destination` | `https://example.com/api` | Forwards the encrypted data to this URL |

## Sample Response

When encrypting data, the response will contain the original JSON structure with the specified fields replaced by encrypted values:

```json theme={null}
{
  "userId": 1,
  "id": 1,
  "title": "qanapi:bm9uZQ:MDFqNDRrZmJmenkyc3ZqbTg1NG5qYng2d2c:dHFkY1Q1MW81Y1hLcTRCdkxibG1DK3NoMnF0ZFE3OFVIa3REbFZwVGpmQT0:$",
  "body": "qanapi:bm9uZQ:MDFqNDRrZmJnOWN4ejYwcHFxOWo3c3huYXE:dzlTdlYwVkNVK0xmVXUwM2JLT2xGQi9rbHF4R1l0MWxCZlR5QlNqeHpZUT0:$"
}
```

## Encrypting Nested JSON Objects

You can encrypt fields within nested JSON objects by using dot notation in the `X-Qanapi-Fields` header:

```bash theme={null}
curl --location 'https://your-tenant.qanapi.cloud/proxy/your-project-id' \
--header 'X-Qanapi-Authorization: your_api_key' \
--header 'X-Qanapi-Mode: encrypt' \
--header 'X-Qanapi-Fields: user.name,user.email,payment.cardNumber' \
--header 'Content-Type: application/json' \
--data '{
    "orderId": "12345",
    "user": {
        "name": "John Doe",
        "email": "john@example.com",
        "role": "customer"
    },
    "payment": {
        "cardNumber": "4111111111111111",
        "expiryDate": "12/25"
    }
}'
```

## Encrypting Arrays

To encrypt items in an array, specify the field name in the `X-Qanapi-Fields` header. All items in the array will be encrypted:

```bash theme={null}
curl --location 'https://your-tenant.qanapi.cloud/proxy/your-project-id' \
--header 'X-Qanapi-Authorization: your_api_key' \
--header 'X-Qanapi-Mode: encrypt' \
--header 'X-Qanapi-Fields: tags,comments' \
--header 'Content-Type: application/json' \
--data '{
    "postId": 123,
    "tags": ["sensitive", "personal", "private"],
    "comments": ["Great post!", "Contains personal info"]
}'
```

## Error Handling

Common errors when encrypting data include:

| Error Code | Description          | Solution                                                     |
| ---------- | -------------------- | ------------------------------------------------------------ |
| 401        | Unauthorized         | Check your API key                                           |
| 400        | Bad Request          | Ensure your JSON is valid and fields are correctly specified |
| 422        | Unprocessable Entity | Check that the fields you specified exist in your payload    |
| 429        | Too Many Requests    | You've exceeded the rate limit, wait and try again           |

## Best Practices for Encryption

1. **Only encrypt sensitive fields** - Don't encrypt everything, focus on sensitive data
2. **Store encrypted data securely** - Even though the data is encrypted, follow good security practices
3. **Document encrypted fields** - Keep track of which fields are encrypted in your application
4. **Handle errors gracefully** - Implement proper error handling in your application

## Next Steps

* [Learn how to decrypt data](/api-v1/data-proxies/decryption)
* [Set up forwarding of encrypted data](/api-v1/data-proxies/forwarding)
* [Explore language-specific examples](/api-v1/examples/curl)