git-crypt man page

git-crypt ā€” transparent file encryption in Git

Synopsis

git-crypt [OPTIONS] COMMAND [ARGS...]

Common Commands

git-crypt init

git-crypt status

git-crypt lock

GPG Commands

git-crypt add-gpg-user GPG_USER_ID

git-crypt unlock

Symmetric Key Commands

git-crypt export-key OUTPUT_KEY_FILE

git-crypt unlock KEY_FILE

Description

git-crypt enables transparent encryption and decryption of files in a git repository. Files which you choose to protect are encrypted when committed, and decrypted when checked out. git-crypt lets you freely share a repository containing a mix of public and private content. git-crypt gracefully degrades, so developers without the secret key can still clone and commit to a repository with encrypted files. This lets you store your secret material (such as keys or passwords) in the same repository as your code, without requiring you to lock down your entire repository.

Commands

git-crypt is logically divided into several sub-commands which perform distinct tasks. Each sub-command, and its arguments, are documented below. Note that arguments and options to sub-commands must be specified on the command line after the name of the sub-command.

init [OPTIONS]

Generate a key and prepare the current Git repository to use git-crypt.

The following options are understood:

-k KEY_NAME, --key-name KEY_NAME

Initialize the given key instead of the default key. git-crypt supports multiple keys per repository, allowing you to share different files with different sets of collaborators.

status [OPTIONS]

Display a list of files in the repository, with their status (encrypted or unencrypted).

The following options are understood:

-e

Show only encrypted files.

-u

Show only unencrypted files.

-f, --fix

Encrypt files that should be encrypted but were committed to the repository or added to the index without encryption. (This can happen if a file is added before git-crypt is initialized or before the file is added to the gitattributes file.)

add-gpg-user [OPTIONS] GPG_USER_ID...

Add the users with the given GPG user IDs as collaborators. Specifically, git-crypt uses gpg(1) to encrypt the shared symmetric key to the public keys of each GPG user ID, and stores the GPG-encrypted keys in the .git-crypt directory at the root of the repository.

GPG_USER_ID can be a key ID, a full fingerprint, an email address, or anything else that uniquely identifies a public key to GPG (see "HOW TO SPECIFY A USER ID" in the gpg(1) man page).

The following options are understood:

-k KEY_NAME, --key-name KEY_NAME

Grant access to the given key, rather than the default key.

-n, --no-commit

Don't automatically commit the changes to the .git-crypt directory.

--trusted

Assume that the GPG keys specified on the command line are trusted; i.e. they actually belong to the users that they claim to belong to.

Without this option, git-crypt uses the same trust model as GPG, which is based on the Web of Trust by default. Under this model, git-crypt will reject GPG keys that do not have trusted signatures.

If you don't want to use the Web of Trust, you can either change GPG's trust model by setting the trust-model option in ~/.gnupg/gpg.conf (see gpg(1)), or use the --trusted option to add-gpg-user on a case-by-case basis.

unlock [KEY_FILE...]

Decrypt the repository. If one or more key files are specified on the command line, git-crypt attempts to decrypt using those shared symmetric keys. If no key files are specified, git-crypt attempts to decrypt using a GPG-encrypted key stored in the repository's .git-crypt directory.

This command takes no options.

export-key [OPTIONS] FILENAME

Export the repository's shared symmetric key to the given file.

The following options are understood:

-k KEY_NAME, --key-name KEY_NAME

Export the given key, rather than the default key.

help [COMMAND]

Display help for the given COMMAND, or an overview of all commands if no command is specified.

version

Print the currently-installed version of git-crypt. The format of the output is always "git-crypt", followed by a space, followed by the dotted version number.

Using Git-Crypt

First, you prepare a repository to use git-crypt by running git-crypt init.

Then, you specify the files to encrypt by creating a gitattributes(5) file. Each file which you want to encrypt should be assigned the "filter=git-crypt diff=git-crypt" attributes. For example:

secretfile filter=git-crypt diff=git-crypt
*.key filter=git-crypt diff=git-crypt

Like a .gitignore file, .gitattributes files can match wildcards and should be checked into the repository. Make sure you don't accidentally encrypt the .gitattributes file itself (or other git files like .gitignore or .gitmodules). Make sure your .gitattributes rules are in place before you add sensitive files, or those files won't be encrypted!

To share the repository with others (or with yourself) using GPG, run:

git-crypt add-gpg-user GPG_USER_ID

GPG_USER_ID can be a key ID, a full fingerprint, an email address, or anything else that uniquely identifies a public key to GPG. Note: git-crypt add-gpg-user will add and commit a GPG-encrypted key file in the .git-crypt directory of the root of your repository.

Alternatively, you can export a symmetric secret key, which you must securely convey to collaborators (GPG is not required, and no files are added to your repository):

git-crypt export-key /path/to/key

After cloning a repository with encrypted files, unlock with with GPG:

git-crypt unlock

Or with a symmetric key:

git-crypt unlock /path/to/key

That's all you need to do - after git-crypt is set up (either with git-crypt init or git-crypt unlock), you can use git normally - encryption and decryption happen transparently.

The .gitattributes File

The .gitattributes file is documented in gitattributes(5). The file pattern format is the same as the one used by .gitignore, as documented in gitignore(5), with the exception that specifying merely a directory (e.g. "/dir/") is not sufficient to encrypt all files beneath it.

Also note that the pattern "dir/*" does not match files under sub-directories of dir/. To encrypt an entire sub-tree dir/, place the following in dir/.gitattributes:

* filter=git-crypt diff=git-crypt
.gitattributes !filter !diff

The second pattern is essential for ensuring that .gitattributes itself is not encrypted.

Multiple Key Support

In addition to the implicit default key, git-crypt supports alternative keys which can be used to encrypt specific files and can be shared with specific GPG users. This is useful if you want to grant different collaborators access to different sets of files.

To generate an alternative key named KEYNAME, pass the -k KEYNAME option to git-crypt init as follows:

git-crypt init -k KEYNAME

To encrypt a file with an alternative key, use the git-crypt-KEYNAME filter in .gitattributes as follows:

secretfile filter=git-crypt-KEYNAME diff=git-crypt-KEYNAME

To export an alternative key or share it with a GPG user, pass the -k KEYNAME option to git-crypt export-key or git-crypt add-gpg-user as follows:

git-crypt export-key -k KEYNAME /path/to/keyfile
git-crypt add-gpg-user -k KEYNAME GPG_USER_ID

To unlock a repository with an alternative key, use git-crypt unlock normally. git-crypt will automatically determine which key is being used.

See Also

git(1), gitattributes(5), git-crypt home page[1], GitHub repository[2]

Author

Andrew Ayer <agwa@andrewayer.name>

Notes

  1. git-crypt home page
    https://www.agwa.name/projects/git-crypt
  2. GitHub repository
    https://github.com/AGWA/git-crypt

Info

2017-11-26 git-crypt 0.6.0