> For the complete documentation index, see [llms.txt](https://painor.gitbook.io/gramjs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://painor.gitbook.io/gramjs/working-with-files/upload.getcdnfilehashes.md).

# upload.getCdnFileHashes

Get SHA256 hashes for verifying downloaded [CDN](https://core.telegram.org/cdn) files

## Example

{% tabs %}
{% tab title="Javascript" %}

```javascript
const {Api, TelegramClient} = require('telegram');
const {StringSession} = require('telegram/sessions');

const session = new StringSession('');
const client = new TelegramClient(session, apiId, apiHash, {});

(async function run() {
    const result = await client.invoke(new Api.upload.getCdnFileHashes({
        fileToken: Buffer.from('some bytes here'),
        offset: 1930220,
        }));
    console.log(result); // prints the result
})();
```

{% endtab %}

{% tab title="TypeScript" %}

```typescript
import {Api, TelegramClient} from 'telegram';
import {StringSession} from 'telegram/sessions';

const session = new StringSession('');
const client = new TelegramClient(session, apiId, apiHash, {});

(async function run() {
    const result: Api.Vector<FileHash> = await client.invoke(new Api.upload.getCdnFileHashes({
        fileToken: Buffer.from('some bytes here'),
        offset: 1930220,
        }));
    console.log(result); // prints the result
})();
```

{% endtab %}
{% endtabs %}

## TL schema

```
---functions---
upload.getCdnFileHashes#4da54231 file_token:bytes offset:int = Vector<FileHash>;
```

## Parameters

|       Name      | Type                                          | Description                               |
| :-------------: | --------------------------------------------- | ----------------------------------------- |
| **file\_token** | [bytes](https://core.telegram.org/type/bytes) | File                                      |
|    **offset**   | [int](https://core.telegram.org/type/int)     | Offset from which to start getting hashes |

## Result

[Vector](https://core.telegram.org/type/Vector%20t)[\[FileHash\](https://core.telegram.org/type/FileHash)](https://app.gitbook.com/s/-MMkAn4QUh4dOGfc-vjY/working-with-files/\[FileHash]\(https://core.telegram.org/type/FileHash\))

## Possible errors

| Code | Type                 | Description                            |
| :--: | -------------------- | -------------------------------------- |
|  400 | CDN\_METHOD\_INVALID | You can't call this method in a CDN DC |
|  400 | RSA\_DECRYPT\_FAILED | Internal RSA decryption failed         |

## Can bots use this methd ?

### yes

## Related pages

### [Encrypted CDNs for Speed and Security](https://core.telegram.org/cdn)