> For the complete documentation index, see [llms.txt](https://yubico.gitbook.io/yubikey5/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://yubico.gitbook.io/yubikey5/gpg/generate-keys/file-extensions.md).

# File Extensions

Quick reference to the various file extension types.

<table><thead><tr><th width="167"></th><th></th></tr></thead><tbody><tr><td><mark style="color:red;"><strong><code>.gpg</code></strong></mark></td><td>a binary GPG encrypted file</td></tr><tr><td><mark style="color:red;"><strong><code>.asc</code></strong></mark></td><td>an armored GPG key file</td></tr><tr><td><mark style="color:red;"><strong><code>.pub</code></strong></mark></td><td>public key (usually for OpenSSH)</td></tr><tr><td><mark style="color:red;"><strong><code>.sig</code></strong></mark></td><td>a binary GPG signed document / detached signature</td></tr><tr><td><mark style="color:red;"><strong><code>.csr</code></strong></mark></td><td>certificate signing request</td></tr><tr><td><mark style="color:red;"><strong><code>.crt</code></strong></mark></td><td>security certificate file</td></tr><tr><td><mark style="color:red;"><strong><code>.rar.gpg</code></strong></mark></td><td>popular method of encrypting a rar archive with winrar and then using Gpg4win to encrypt and password protect the archive.</td></tr><tr><td><mark style="color:red;"><strong><code>.zip.gpg</code></strong></mark></td><td>a method of encrypting a .zip archive by zipping the contents with WinZip, and then encrypting / password protecting the archive with Gpg4win.</td></tr></tbody></table>