> For the complete documentation index, see [llms.txt](https://rocdu.gitbook.io/ingress-nginx-docs-cn/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://rocdu.gitbook.io/ingress-nginx-docs-cn/docs/examples/customization/ssl-dh-param.md).

# Custom DH parameters for perfect forward secrecy

This example aims to demonstrate the deployment of an nginx ingress controller and use a ConfigMap to configure custom Diffie-Hellman parameters file to help with "Perfect Forward Secrecy".

## Custom configuration

```
$ cat configmap.yaml
apiVersion: v1
data:
  ssl-dh-param: "ingress-nginx/lb-dhparam"
kind: ConfigMap
metadata:
  name: nginx-configuration
  namespace: ingress-nginx
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
```

```
$ kubectl create -f configmap.yaml
```

## Custom DH parameters secret

```
$> openssl dhparam 1024 2> /dev/null | base64
LS0tLS1CRUdJTiBESCBQQVJBTUVURVJ...
```

```
$ cat ssl-dh-param.yaml
apiVersion: v1
data:
  dhparam.pem: "LS0tLS1CRUdJTiBESCBQQVJBTUVURVJ..."
kind: ConfigMap
metadata:
  name: nginx-configuration
  namespace: ingress-nginx
  labels:
    app.kubernetes.io/name: ingress-nginx
    app.kubernetes.io/part-of: ingress-nginx
```

```
$ kubectl create -f ssl-dh-param.yaml
```

## Test

Check the contents of the configmap is present in the nginx.conf file using: `kubectl exec nginx-ingress-controller-873061567-4n3k2 -n kube-system cat /etc/nginx/nginx.conf`