Encrypted secrets

About encrypted secrets

Secrets are encrypted environment variables that you create in an organization or repository. The secrets that you create are available to use in GitHub Actions workflows. GitHub uses a libsodium sealed box to help ensure that secrets are encrypted before they reach GitHub and remain encrypted until you use them in a workflow.

For secrets stored at the organization-level, you can use access policies to control which repositories can use organization secrets. Organization-level secrets let you share secrets between multiple repositories, which reduces the need for creating duplicate secrets. Updating an organization secret in one location also ensures that the change takes effect in all repository workflows that use that secret.

Naming your secrets

The following rules apply to secret names:

• Secret names can only contain alphanumeric characters ([a-z], [A-Z], [0-9]) or underscores (_). Spaces are not allowed.

• Secret names must not start with the GITHUB_ prefix.

• Secret names must not start with a number.

• Secret names are not case-sensitive.

• Secret names must be unique at the level they are created at.

  For example, a secret created at the repository level must have a unique name in that repository, and a secret created at the organization level must have a unique name at that level.

  If a secret with the same name exists at multiple levels, the secret at the lower level takes precedence. For example, if an organization-level secret has the same name as a repository-level secret, then the repository-level secret takes precedence.

To help ensure that GitHub redacts your secret in logs, avoid using structured data as the values of secrets. For example, avoid creating secrets that contain JSON or encoded Git blobs.

Accessing your secrets

To make a secret available to an action, you must set the secret as an input or environment variable in the workflow file. Review the action's README file to learn about which inputs and environment variables the action expects. For more information, see "Workflow syntax for GitHub Actions."

You can use and read encrypted secrets in a workflow file if you have access to edit the file. For more information, see "Access permissions on GitHub."

You can also manage secrets using the REST API. For more information, see "Secrets."

Limiting credential permissions

When generating credentials, we recommend that you grant the minimum permissions possible. For example, instead of using personal credentials, use deploy keys or a service account. Consider granting read-only permissions if that's all that is needed, and limit access as much as possible. When generating a personal access token (PAT), select the fewest scopes necessary.

Creating encrypted secrets for a repository

To create secrets for a user account repository, you must be the repository owner. To create secrets for an organization repository, you must have admin access.

gh secret set secret-name

gh secret set secret-name < secret.txt

Creating encrypted secrets for an organization

When creating a secret in an organization, you can use a policy to limit which repositories can access that secret. For example, you can grant access to all repositories, or limit access to only private repositories or a specified list of repositories.

To create secrets at the organization level, you must have admin access.

gh auth login --scopes "admin:org"

gh secret set --org organization-name secret-name

gh secret set --org organization-name secret-name --visibility all

gh secret set --org organization-name secret-name --repos repo-name-1,repo-name-2"

gh secret list --org organization-name

Reviewing access to organization-level secrets

You can check which access policies are being applied to a secret in your organization.

1. On your GitHub Enterprise Server instance, navigate to the main page of the organization.

2. Under your organization name, click Settings.

   

1. In the left sidebar, click Secrets.

2. The list of secrets includes any configured permissions and policies. For example:

3. For more details on the configured permissions for each secret, click Update.

Using encrypted secrets in a workflow

To provide an action with a secret as an input or environment variable, you can use the secrets context to access secrets you've created in your repository. For more information, see "Contexts" and "Workflow syntax for GitHub Actions."

steps:
  - name: Hello world action
    with: # Set the secret as an input
      super_secret: ${{ secrets.SuperSecret }}
    env: # Or as an environment variable
      super_secret: ${{ secrets.SuperSecret }}

Avoid passing secrets between processes from the command line, whenever possible. Command-line processes may be visible to other users (using the ps command) or captured by security audit events. To help protect secrets, consider using environment variables, STDIN, or other mechanisms supported by the target process.

If you must pass secrets within a command line, then enclose them within the proper quoting rules. Secrets often contain special characters that may unintentionally affect your shell. To escape these special characters, use quoting with your environment variables. For example:

Example using Bash

steps:
  - shell: bash
    env:
      SUPER_SECRET: ${{ secrets.SuperSecret }}
    run: |
      example-command "$SUPER_SECRET"

Example using PowerShell

steps:
  - shell: pwsh
    env:
      SUPER_SECRET: ${{ secrets.SuperSecret }}
    run: |
      example-command "$env:SUPER_SECRET"

Example using Cmd.exe

steps:
  - shell: cmd
    env:
      SUPER_SECRET: ${{ secrets.SuperSecret }}
    run: |
      example-command "%SUPER_SECRET%"

Limits for secrets

You can store up to 1,000 organization secrets and 100 repository secrets.

A workflow created in a repository can access the following number of secrets:

• All 100 repository secrets.
• If the repository is assigned access to more than 100 organization secrets, the workflow can only use the first 100 organization secrets (sorted alphabetically by secret name).

Secrets are limited to 64 KB in size. To use secrets that are larger than 64 KB, you can store encrypted secrets in your repository and save the decryption passphrase as a secret on GitHub. For example, you can use gpg to encrypt your credentials locally before checking the file in to your repository on GitHub. For more information, see the "gpg manpage."

1. Run the following command from your terminal to encrypt the my_secret.json file using gpg and the AES256 cipher algorithm.

   $ gpg --symmetric --cipher-algo AES256 my_secret.json

2. You will be prompted to enter a passphrase. Remember the passphrase, because you'll need to create a new secret on GitHub that uses the passphrase as the value.

3. Create a new secret that contains the passphrase. For example, create a new secret with the name LARGE_SECRET_PASSPHRASE and set the value of the secret to the passphrase you selected in the step above.

4. Copy your encrypted file into your repository and commit it. In this example, the encrypted file is my_secret.json.gpg.

5. Create a shell script to decrypt the password. Save this file as decrypt_secret.sh.

   #!/bin/sh
   
   # Decrypt the file
   mkdir $HOME/secrets
   # --batch to prevent interactive command
   # --yes to assume "yes" for questions
   gpg --quiet --batch --yes --decrypt --passphrase="$LARGE_SECRET_PASSPHRASE" \
   --output $HOME/secrets/my_secret.json my_secret.json.gpg

6. Ensure your shell script is executable before checking it in to your repository.

   $ chmod +x decrypt_secret.sh
   $ git add decrypt_secret.sh
   $ git commit -m "Add new decryption script"
   $ git push

7. From your workflow, use a step to call the shell script and decrypt the secret. To have a copy of your repository in the environment that your workflow runs in, you'll need to use the actions/checkout action. Reference your shell script using the run command relative to the root of your repository.

   name: Workflows with large secrets
   
   on: push
   
   jobs:
     my-job:
       name: My Job
       runs-on: ubuntu-latest
       steps:
         - uses: actions/checkout@v2
         - name: Decrypt large secret
           run: ./.github/scripts/decrypt_secret.sh
           env:
             LARGE_SECRET_PASSPHRASE: ${{ secrets.LARGE_SECRET_PASSPHRASE }}
         # This command is just an example to show your secret being printed
         # Ensure you remove any print statements of your secrets. GitHub does
         # not hide secrets that use this workaround.
         - name: Test printing your secret (Remove this step in production)
           run: cat $HOME/secrets/my_secret.json
   

Storing Base64 binary blobs as secrets

You can use Base64 encoding to store small binary blobs as secrets. You can then reference the secret in your workflow and decode it for use on the runner. For the size limits, see "Limits for secrets".

1. Use base64 to encode your file into a Base64 string. For example:

   $ base64 -i cert.der -o cert.base64
   

2. Create a secret that contains the Base64 string. For example:

   $ gh secret set CERTIFICATE_BASE64 < cert.base64
   ✓ Set secret CERTIFICATE_BASE64 for octocat/octorepo
   

3. To access the Base64 string from your runner, pipe the secret to base64 --decode. For example:

   name: Retrieve Base64 secret
   on:
     push:
       branches: [ octo-branch ]
   jobs:
     decode-secret:
       runs-on: ubuntu-latest
       steps:
         - uses: actions/checkout@v2
         - name: Retrieve the secret and decode it to a file
           env:
             CERTIFICATE_BASE64: ${{ secrets.CERTIFICATE_BASE64 }}
           run: |
             echo $CERTIFICATE_BASE64 | base64 --decode > cert.der
         - name: Show certificate information
           run: |
             openssl x509 -in cert.der -inform DER -text -noout