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# AWS::EC2::VPNConnection Phase1EncryptionAlgorithmsRequestListValue
<a name="aws-properties-ec2-vpnconnection-phase1encryptionalgorithmsrequestlistvalue"></a>

Specifies the encryption algorithm for the VPN tunnel for phase 1 IKE negotiations.

## Syntax
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To declare this entity in your CloudFormation template, use the following syntax:

### JSON
<a name="aws-properties-ec2-vpnconnection-phase1encryptionalgorithmsrequestlistvalue-syntax.json"></a>

```
{
  "[Value](#cfn-ec2-vpnconnection-phase1encryptionalgorithmsrequestlistvalue-value)" : String
}
```

### YAML
<a name="aws-properties-ec2-vpnconnection-phase1encryptionalgorithmsrequestlistvalue-syntax.yaml"></a>

```
  [Value](#cfn-ec2-vpnconnection-phase1encryptionalgorithmsrequestlistvalue-value): String
```

## Properties
<a name="aws-properties-ec2-vpnconnection-phase1encryptionalgorithmsrequestlistvalue-properties"></a>

`Value`  <a name="cfn-ec2-vpnconnection-phase1encryptionalgorithmsrequestlistvalue-value"></a>
The value for the encryption algorithm.  
*Required*: No  
*Type*: String  
*Allowed values*: `AES128 | AES256 | AES128-GCM-16 | AES256-GCM-16`  
*Update requires*: [No interruption](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)