Before you can access or interact with hosted repositories from your system, you
must set up local authentication in your environment.
After you set up local authentication, you can access hosted repositories for
which you have the appropriate
[roles and permissions](https://docs.cloud.google.com/source-repositories/docs/configure-access-control.md.txt).
You can also perform standard Git operations such as `git clone`, `git pull`,
and `git push`. Local authentication isn't required to perform operations in the
Google Cloud console, for example, to browse the contents of a repository.
Cloud Source Repositories supports the following types of authentication:
- [SSH](https://docs.cloud.google.com/source-repositories/docs/authentication.md.txt#ssh)
- [Google Cloud CLI](https://docs.cloud.google.com/source-repositories/docs/authentication.md.txt#authenticate-using-the-cloud-sdk)
- [Manually generated credentials](https://docs.cloud.google.com/source-repositories/docs/authentication.md.txt#manually-generated-credentials)
## Authenticate by using SSH
Cloud Source Repositories lets you use SSH public key authentication to
access hosted repositories. In this scenario, you first generate a key pair on
the local system from which you want to access the repository. Then you register
the public key with Google Cloud. If you already have an SSH key pair
on your system, you can re-use those keys for authentication. You can register
up to 20 public keys per Google Account.
> [!NOTE]
> **Note:** You cannot configure authentication for service accounts by using SSH keys.
Cloud Source Repositories supports three SSH key types:
- RSA (only for keys with more than 2048 bits)
- ECDSA
- ED25519
### Generate a key pair
The SSH key pair consists of a private key that resides on your local system and
a public key that you register with Google Cloud.
### Linux or macOS
1. Ensure that
[OpenSSH](https://www.openssh.com/)
is installed on your local system.
2. At a command prompt, enter the following command:
```bash
ssh-keygen -t [KEY_TYPE] -C "[USER_EMAIL]"
```
Where:
- `[USER_EMAIL]` is your email address.
- `[KEY_TYPE]` is one of the following:
- `rsa`
- `ecdsa`
- `ed25519`
For example:
```bash
ssh-keygen -t rsa -C "user@example.com"
```
1. When prompted, enter a filename for the public key file. To accept the
default `~/.ssh` location, press **Enter**, otherwise specify a filename.
2. When prompted, leave the passphrase empty and press **Enter**.
3. [Register your key](https://docs.cloud.google.com/source-repositories/docs/authentication.md.txt#register_a_public_key)
### Windows
1. Ensure that
[PuTTY](https://www.chiark.greenend.org.uk/%7Esgtatham/putty/latest.html)
is installed on your local system.
2. From the Windows **Start** menu, start PuTTYGen.
3. In the window that opens, select the key type from the **Parameters**
field.
4. Click **Generate**.
PuTTYGen displays the generated public key string.
5. Specify a passphrase to protect the key pair.
6. To save the key pair you generated to your local system, click
**Save Public Key** and **Save Private Key**.
### Use existing keys
You can also use an existing key pair for SSH authentication.
### Linux or macOS
By default, public key files are located in your `~/.ssh` directory.
At a command prompt, enter the following command:
```bash
ls -a ~/.ssh
```
The default filenames are:
- `id_rsa.pub`
- `id_ecdsa.pub`
- `id_ed25519.pub`
### Windows
1. From the Windows **Start** menu, start PuTTYGen.
2. In the window that opens, click **Load**.
3. Browse the local file system for your public key file and select the
file.
PuTTYGen displays the public key string. If you specified a passphrase
when you saved the key file, PuTTYGen prompts you to enter it before you
can view the public key.
### Register a public key
1. In the Google Cloud console, open the **Manage SSH Keys** page.
[Open Cloud Source Repositories](https://source.cloud.google.com/user/ssh_keys)
2. Click **Register SSH key**.
The **Register SSH Key** dialog opens.
3. In the **Key name** field, type a unique name for the key.
4. In the **Key** field, copy the key string from your public key file.
5. Click **Register**.
After you set up SSH authentication, you can
[clone any repository](https://docs.cloud.google.com/source-repositories/docs/cloning-repositories.md.txt#ssh)
for which you have the required roles and permissions, or
[push the contents](https://docs.cloud.google.com/source-repositories/docs/pushing-code-from-a-repository.md.txt)
of a local repository to an empty hosted repository.
## Authenticate by using the gcloud CLI
Cloud Source Repositories lets you authenticate by using the
gcloud CLI. In this scenario, you run the
[`gcloud init`](https://docs.cloud.google.com/sdk/gcloud/reference/init)
command on your system to set up local authentication.
1. Ensure that the
[gcloud CLI](https://docs.cloud.google.com/sdk/install)
is installed on your local system.
2. At a command prompt, run `gcloud init`:
```bash
gcloud init
```
3. Follow the instructions.
After you set up authentication by using the gcloud CLI, you can use
standard Git commands to interact with the hosted repository on
Cloud Source Repositories.
## Authenticate by using manually generated credentials
You can also use manually generated credentials for authentication.
Cloud Source Repositories provides a set of scripts you can use to manually
generate the credentials you need to access hosted repositories.
1. Go to the **Configure Git** page to generate your credentials.
[Go to the Configure Git page](https://source.developers.google.com/auth/start?scopes=https://www.googleapis.com/auth/cloud-platform)
2. Open a terminal window.
3. Type the following command:
```
git clone https://source.developers.google.com/p/PROJECT_ID/r/REPOSITORY_NAME
```
Where:
- PROJECT_ID is the name of your project
- REPOSITORY_NAME is the name of your repository
After you set up authentication with manually generated credentials, you can
interact with the hosted repository on Cloud Source Repositories by using the
standard Git commands.