The git verify-commit command is a Git utility that allows you to check the GPG (GNU Privacy Guard) verification status of commits within a Git repository. GPG signatures are cryptographic signatures attached to commits to verify their authenticity and integrity. This command is useful for ensuring that commits in a Git repository have been signed and verified, which is crucial for maintaining the security and trustworthiness of a project’s history. Here’s a more detailed explanation of what you can do with git verify-commit:
Checking Commit Verification: The primary purpose of git verify-commit is to check whether commits in the Git history have been verified using GPG signatures. When you run this command, it will inspect the entire commit history and report on the verification status of each commit.
# git verify-commit
If a commit has been signed and the GPG signature is valid, git verify-commit will report that the commit is verified. If a commit is not signed or its signature is invalid, the command will report that the commit is not verified. This allows you to quickly identify any commits that lack proper verification, which can be especially important for ensuring the authenticity of commits in a collaborative or open-source project.
GPG Signatures: To sign a Git commit with a GPG key, you would typically use the -S or –gpg-sign option when making a commit. This adds a cryptographic signature to the commit object, which can later be verified using git verify-commit.
# git commit -S -m "Your commit message"
Enforcing Commit Verification: In some Git workflows or organizations, it might be mandatory for all commits to be signed and verified. git verify-commit can be used in pre-commit or pre-push hooks to enforce this policy, preventing unverified commits from being pushed to a shared repository.
Configuring GPG Settings: To use GPG with Git, you need to configure your GPG key and Git settings appropriately. You can set up your GPG key and configure Git to use it for signing commits by following the instructions in Git’s documentation.
# git config --global user.signingkey YOUR_GPG_KEY_ID # git config --global commit.gpgsign true
Replace YOUR_GPG_KEY_ID with the actual ID of your GPG key.
Understanding Commit Trust: GPG signatures not only ensure the authenticity of commits but also provide a level of trust in the author of the commit. This is especially important in open-source projects and collaboration scenarios where contributors may not have direct trust relationships.
Public Key Infrastructure (PKI): GPG-based commit verification is a form of Public Key Infrastructure (PKI) used in Git to verify that the commits were made by the legitimate authors and have not been tampered with during transit.
“git verify-commit” Command Examples
1. Check commits for a GPG signature:
# git verify-commit commit_hash1 optional_commit_hash2 ...
2. Check commits for a GPG signature and show details of each commit:
# git verify-commit commit_hash1 optional_commit_hash2 ... --verbose
3. Check commits for a GPG signature and print the raw details:
# git verify-commit commit_hash1 optional_commit_hash2 ... --raw
In summary, git verify-commit is a valuable Git command for checking the GPG verification status of commits within a repository. It helps maintain the integrity and security of a Git project by ensuring that commits are properly signed and verified. You can use this command to enforce commit verification policies, identify unverified commits, and establish trust in the commit history of your project. For detailed information on the git verify-commit command and its options, you can refer to the official Git documentation at https://git-scm.com/docs/git-verify-commit.