> For the complete documentation index, see [llms.txt](https://docs.bayunsystems.com/bayuncoresdk-python/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.bayunsystems.com/bayuncoresdk-python/bayuncoresdk-operations/lock-unlock-binary-data.md).

# 5.3 Lock/Unlock Binary Data

## 5**.3.1 Lock Binary Data**

The `lockData` function of `BayunCore` class locks binary data with default encryption-policy dictated by server settings.

The function takes the following parameters :

* **sessionId** : Unique SessionId which is received in the authenticate function response.
* **data** : Data to be locked.
  * dataType : `bytes`
* **data\_len** : Length of the data to be locked.

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

```python
data = b'Hello World!'
data_len = len(data)
lockDataOutput = bayunCore.lockData("<sessionId>", data, data_len)
locked_data = lockDataOutput.data
locked_binary_data = locked_data.tobytes()
locked_binary_data_len = lockDataOutput.data_len
```

{% endtab %}
{% endtabs %}

## **5.3.2 Lock Binary Data with encryption-policy**

The `lockData` function with encryption-policy as an optional parameter locks data with the encryption key dictated by the policy. The function takes the following parameters :

* **sessionId** : Unique SessionId which is received in the authenticate function response.
* **data** : Data to be locked.
  * dataType : `bytes`
* **data\_len** : Length of the data to be locked.
* **encryptionPolicy** : [BayunEncryptionPolicy](https://docs.bayunsystems.com/bayuncoresdk-python/bayuncoresdk-operations#encryption-policy) determines the key for locking.
* **keyGenerationPolicy** : [BayunKeyGenerationPolicy](https://docs.bayunsystems.com/bayuncoresdk-python/bayuncoresdk-operations#key-generation-policy) determines the policy to generate the data encryption key.
* **groupId** : GroupId is required if encryptionPolicy is `BayunEncryptionPolicyGroup`.

{% hint style="info" %}
Note : If encryption-policy is other than `BayunEncryptionPolicyGroup` then groupId should be empty string.
{% endhint %}

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

```python
from BayunCore import BayunEncryptionPolicy
from BayunCore import BayunKeyGenerationPolicy

data = b'Hello World!'
data_len = len(data)
encryptionPolicy = BayunEncryptionPolicy.Company
keyGenerationPolicy = BayunKeyGenerationPolicy.Static
lockDataOutput = bayunCore.lockData("<sessionId>", data, data_len, encryptionPolicy, keyGenerationPolicy, "<groupId>")
locked_data = lockDataOutput.data
locked_binary_data = locked_data.tobytes()
locked_binary_data_len = lockDataOutput.data_len
```

{% endtab %}
{% endtabs %}

## **5.3.3 Unlock Binary Data**

The `unlockData` function of `BayunCore` class unlocks a locked binary data. The function takes the following parameters :

* **sessionId** : Unique SessionId which is received in the authenticate function response.
* **data** : Data to be unlocked.
  * dataType : `bytes`
* **data\_len** : Length of data to be unlocked.

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

```python
unlockData_output =  bayunCore.unlockData(sessionId, <data>, <data_len>)
unlocked_data = unlockData_output.data
unlocked_binary_data = unlocked_data.tobytes()
unlocked_binary_data_len = unlockData_output.data_len
```

{% endtab %}
{% endtabs %}


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