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[Deploy tokens](../user/project/deploy_tokens/index.md) allow you to download (`git clone`) or push and pull packages and container registry images of a project without having a user and a password. Deploy tokens cannot be used with the GitLab API.
Deploy tokens can be managed by project maintainers and owners.
## Deploy keys
[Deploy keys](../user/project/deploy_keys/index.md) allow read-only or read-write access to your repositories by importing an SSH public key into your GitLab instance. Deploy keys cannot be used with the GitLab API or the registry.
This is useful, for example, for cloning repositories to your Continuous Integration (CI) server. By using deploy keys, you don't have to set up a fake user account.
Runner registration tokens are used to [register](https://docs.gitlab.com/runner/register/) a [runner](https://docs.gitlab.com/runner/) with GitLab. Group or project owners or instance administrators can obtain them through the GitLab user interface. The registration token is limited to runner registration and has no further scope.
You can use the runner registration token to add runners that execute jobs in a project or group. The runner has access to the project's code, so be careful when assigning project and group-level permissions.
## Runner authentication tokens (also called runner tokens)
After registration, the runner receives an authentication token, which it uses to authenticate with GitLab when picking up jobs from the job queue. The authentication token is stored locally in the runner's [`config.toml`](https://docs.gitlab.com/runner/configuration/advanced-configuration.html) file.
In case of Docker Machine/Kubernetes/VirtualBox/Parallels/SSH executors, the execution environment has no access to the runner authentication token, because it stays on the runner machine. They have access to the job token only, which is needed to execute the job.
Malicious access to a runner's file system may expose the `config.toml` file and thus the authentication token, allowing an attacker to [clone the runner](https://docs.gitlab.com/runner/security/#cloning-a-runner).
API authentication uses the job token, by using the authorization of the user
triggering the job.
The job token is secured by its short life-time and limited scope. It could possibly be leaked if multiple jobs run on the same machine ([like with the shell runner](https://docs.gitlab.com/runner/security/#usage-of-shell-executor)). On Docker Machine runners, configuring [`MaxBuilds=1`](https://docs.gitlab.com/runner/configuration/advanced-configuration.html#the-runnersmachine-section) is recommended to make sure runner machines only ever run one build and are destroyed afterwards. This may impact performance, as provisioning machines takes some time.
## Available scopes
This table shows available scopes per token. Scopes can be limited further on token creation.
1. Runner registration and authentication token don't provide direct access to repositories, but can be used to register and authenticate a new runner that may execute jobs which do have access to the repository
Access tokens should be treated like passwords and kept secure.
Adding them to URLs is a security risk. This is especially true when cloning or adding a remote, as Git then writes the URL to its `.git/config` file in plain text. URLs are also generally logged by proxies and application servers, which makes those credentials visible to system administrators.
