# 6.4 Get Locking Key

Most developers do not need to use this function, and should instead rely on appropriate lock/unlock methods for encrypting and decrypting all data. This is meant only for highly advanced use-cases where the developer needs to use some custom encryption algorithm and/or explicitly add/validate signatures on some special piece of data or stream which can’t be easily passed to standard lock/unlock methods. In this case, the keys returned by this function should be used very carefully for a single object or stream, and then destroyed immediately after encryption/decryption or signature generation/verification is done.

The `getLockingKey` function of `BayunCore` class returns locking key along with the keys for signature generation and signature verification for an encryption policy. 

The function takes the following parameters :

* **encryptionPolicy** : [BayunEncryptionPolicy](https://bayun.gitbook.io/bayuncoresdk-android/5.-bayuncoresdk-methods#encryption-policy) determines the key to be used to generate the lockingKey.
* **keyGenerationPolicy** : [BayunKeyGenerationPolicy](https://bayun.gitbook.io/bayuncoresdk-android/5.-bayuncoresdk-methods#key-generation-policy) determine the policy to be used to generate the lockingKey.
* **groupId** : GroupId is required if encryptionPolicy is `BayunEncryptionPolicyGroup`. If encryption-policy is other than `BayunEncryptionPolicyGroup` then groupId should be empty string.

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

```java
import com.bayun_module.LockingKeys

int encryptionPolicy =encryptionPolicy;         //bayunCore.ENCRYPTION_POLICY_DEFAULT
int keyGenerationPolicy =keyGenerationPolicy;    //bayunCore.KEY_GENERATION_POLICY_STATIC
String groupId = "<groupId>";

LockingKeys lockingKeys = bayunCore.getLockingKey(encryptionPolicy, keyGenerationPolicy, groupId);


```

{% endtab %}

{% tab title="Kotlin" %}

```kotlin
 import com.bayun_module.LockingKeys
 
 val encryptionPolicy:Int =encryptionPolicy         //bayunCore.ENCRYPTION_POLICY_DEFAULT
 val keyGenerationPolicy:Int =keyGenerationPolicy    //bayunCore.KEY_GENERATION_POLICY_STATIC
 val groupId = "groupId"
 
 var lockingKeys :LockingKeys= bayunCore.getLockingKey(encryptionPolicy, keyGenerationPolicy, groupId)
```

{% endtab %}
{% endtabs %}

The `getLockingKey` function returns a struct `LockingKeys`.

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

```java
public class LockingKeys {
    public String key;//Locking Key
    public String signatureKey; //Private Key to be used for signature generation
    public String signatureVerificationKey; //Private Key to be used for signature generation
}
```

{% endtab %}

{% tab title="Kotlin" %}

```kotlin
class LockingKeys {
            var key : String? = null //Locking Key
            var signatureKey : String? = null  //Private Key to be used for signature generation
            var signatureVerificationKey : String? = null  //Private Key to be used for signature generation
        }
```

{% endtab %}
{% endtabs %}


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