About commit signature verification
You can sign commits and tags locally, to give other people confidence about the origin of a change you have made. If a commit or tag has a GPG, SSH, or S/MIME signature that is cryptographically verifiable, GitHub marks the commit or tag "Verified" or "Partially verified."
For most individual users, GPG or SSH will be the best choice for signing commits. S/MIME signatures are usually required in the context of a larger organization. SSH signatures are the simplest to generate. You can even upload your existing authentication key to GitHub to also use as a signing key. Generating a GPG signing key is more involved than generating an SSH key, but GPG has features that SSH does not. A GPG key can expire or be revoked when no longer used. GitHub shows commits that were signed with such a key as "Verified" unless the key was marked as compromised. SSH keys don't have this capability.
Commits and tags have the following verification statuses, depending on whether you have enabled vigilant mode. By default vigilant mode is not enabled. For information on how to enable vigilant mode, see "Displaying verification statuses for all of your commits."
Signing commits differs from signing off on a commit. For more information about signing off on commits, see "Managing the commit signoff policy for your repository."
Default statuses
| Status | Description |
|---|---|
| Verified | The commit is signed and the signature was successfully verified. |
| Unverified | The commit is signed but the signature could not be verified. |
| No verification status | The commit is not signed. |
Signature verification for rebase and merge
Ao usar a opção Trocar base e Mesclar em uma solicitação de pull, é importante observar que os commits no branch principal são adicionados ao branch base sem verificação de assinatura de commit. Quando você usa essa opção, o GitHub cria um commit modificado usando os dados e o conteúdo do commit original. Isso significa que o GitHub não criou de fato esse commit e, portanto, não pode assiná-lo como um usuário genérico do sistema. O GitHub não tem acesso às chaves de assinatura privadas do responsável pelo commit, portanto, não pode assinar o commit em nome do usuário.
Uma solução alternativa é trocar a base e fazer a mesclagem localmente e depois enviar as alterações por push ao branch base da solicitação de pull.
For more information, see "Rebasing and merging your commits."
Statuses with vigilant mode enabled
| Status | Descrição |
|---|---|
| Verificado | O commit foi assinado, a assinatura foi verificada com sucesso e o committer é o único autor que habilitou o modo vigilante. |
| Parcialmente verificado | O commit foi assinado e a assinatura foi verificada com sucesso, mas o commit tem um autor que: a) não é o committer e b) habilitou o modo vigilante. Neste caso, a assinatura de commit não garante o consentimento do autor. Portanto o commit é verificado apenas parcialmente. |
| Não verificado | Qualquer uma das seguintes opções é verdadeira: – O commit foi assinado, mas não foi possível verificar a assinatura. – O commit não foi assinado, e o usuário que o fez habilitou o modo vigilante. – O commit não foi assinado, e um autor habilitou o modo vigilante. |
Repository administrators can enforce required commit signing on a branch to block all commits that are not signed and verified. For more information, see "About protected branches."
Você pode conferir o status de verificação de seus commits ou tags assinados no GitHub e ver por que as assinaturas de commit podem não ter sido verificadas. Para obter mais informações, confira "Como verificar o status do commit e da verificação de assinatura da tag".
GitHub will automatically use GPG to sign commits you make using the web interface. Commits signed by GitHub will have a verified status. You can verify the signature locally using the public key available at https://github.com/web-flow.gpg. The full fingerprint of the key is 5DE3 E050 9C47 EA3C F04A 42D3 4AEE 18F8 3AFD EB23.
You can optionally choose to have GitHub GPG sign commits you make in GitHub Codespaces. For more information about enabling GPG verification for your codespaces, see "Managing GPG verification for GitHub Codespaces."
GPG commit signature verification
You can use GPG to sign commits with a GPG key that you generate yourself.
GitHub uses OpenPGP libraries to confirm that your locally signed commits and tags are cryptographically verifiable against a public key you have added to your account on GitHub.com.
To sign commits using GPG and have those commits verified on GitHub, follow these steps:
- Check for existing GPG keys
- Generate a new GPG key
- Add a GPG key to your GitHub account
- Tell Git about your signing key
- Sign commits
- Sign tags
SSH commit signature verification
You can use SSH to sign commits with an SSH key that you generate yourself. For more information, see the Git reference documentation for user.Signingkey. If you already use an SSH key to authenticate with GitHub,
you can also upload that same key again for use as a signing key. There's no limit on the number of signing keys you can add to your account.
GitHub uses ssh_data, an open source Ruby library, to confirm that your locally signed commits and tags are cryptographically verifiable against a public key you have added to your account on GitHub.com.
Note: SSH signature verification is available in Git 2.34 or later. To update your version of Git, see the Git website.
To sign commits using SSH and have those commits verified on GitHub, follow these steps:
- Check for existing SSH keys
- Generate a new SSH key
- Add a SSH signing key to your GitHub account
- Tell Git about your signing key
- Sign commits
- Sign tags
S/MIME commit signature verification
You can use S/MIME to sign commits with an X.509 key issued by your organization.
GitHub uses the Debian ca-certificates package, the same trust store used by Mozilla browsers, to confirm that your locally signed commits and tags are cryptographically verifiable against a public key in a trusted root certificate.
Observação: a verificação de assinatura S/MIME está disponível no Git 2.19 ou posterior. Para atualizar sua versão do Git, acesse o site do Git.
To sign commits using S/MIME and have those commits verified on GitHub, follow these steps:
You don't need to upload your public key to GitHub.
Signature verification for bots
Organizations and GitHub Apps that require commit signing can use bots to sign commits. If a commit or tag has a bot signature that is cryptographically verifiable, GitHub marks the commit or tag as verified.
Signature verification for bots will only work if the request is verified and authenticated as the GitHub App or bot and contains no custom author information, custom committer information, and no custom signature information, such as Commits API.