Encryption

It can be useful to manage confidential files, like SSH keys, across multiple systems. However, doing so would put plain text data into a Git repository, which often resides on a public system. yadm implements a feature which can make it easy to encrypt and decrypt a set of files so the encrypted version can be maintained in the Git repository. This feature will only work if the gpg or openssl commands are available. To use OpenSSL see the section lower on this page. It is recommended that you use a private repository when keeping confidential files, even though they are encrypted.

To use this feature, a list of patterns must be created and saved as $HOME/.config/yadm/encrypt. For example:

.ssh/*.key

The yadm encrypt command will find all files matching the patterns, and prompt for a password. Once a password has confirmed, the matching files will be encrypted and saved as $HOME/.local/share/yadm/archive. The patterns and archive should be added to the yadm repository so they are available across multiple systems.

yadm add .config/yadm/encrypt
yadm add .local/share/yadm/archive

To decrypt these files later, or on another system run yadm decrypt and provide the correct password. By default, any decrypted files will have their “group” and “others” permissions removed.

Asymmetric Encryption

Symmetric encryption is used by default, but asymmetric encryption may be enabled using the yadm.gpg-recipient configuration. To do so, run:

yadm config yadm.gpg-recipient <recipient-address>

For this to work, <recipient-address> must exist in your gpg keyrings.

OpenSSL

OpenSSL can be used instead of gpg by specifying the option yadm.cipher, setting it to “openssl”.

yadm config yadm.cipher openssl

There are a few other options to control how the OpenSSL archive is created.

  • yadm.openssl-ciphername determines the cipher algorithm used. “aes-256-cbc” is used by default.
  • yadm.openssl-old is a boolean option that uses parameters more suitable for older versions of OpenSSL. This option defaults to “false”.

transcrypt & git-crypt

transcrypt & git-crypt are tools that enable transparent encryption and decryption of files in a Git repository. If installed, you can use either of these tools with your yadm repository.

Simply use it normally, prefacing the transcrypt or git-crypt commands with yadm.

Learn more about these tools here:

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