Yet another sysadmin's personal blog Zola 2017-09-06T21:46:24+00:00 https://univers-libre.net/tags/openssh/atom.xml 2017-09-06T21:46:24+00:00 2017-09-06T21:46:24+00:00 Romain https://univers-libre.net/posts/convert-ssh-keys/ <p>An SSH key can be stored in multiple format. <code>ssh-keygen</code> from OpenSSH generates keys in its own format, but other SSH implementations can use other formats. PuTTY for example generates keys in RFC4716 format, which looks like this:</p> <pre class="giallo z-code" ><code data-lang="plain"><span class="giallo-l"><span>-----BEGIN RSA PUBLIC KEY-----</span></span> <span class="giallo-l"><span>MIIBCgK349HFUE929fXGEvWmegnBGSuS+rU9soUg2FnODva32D1AqhwdziwHINFa</span></span> <span class="giallo-l"><span>D1MVlcrYG6XRKfkcIFEO929JFNEJONBSEVCgJjtHAGZIm5GL/KA86KDp/CwDFMSw</span></span> <span class="giallo-l"><span>luowcXwDwoyinmeOY9eKyh6aY72xJh7noLBBq1N0bWi1e2i+83txOCg4yV2oVXhB</span></span> <span class="giallo-l"><span>o8pYEJ8LT3el6Smxol3C1oFMVdwPgc0vTl25XucMcG/ALE/KNY6pqC2AQ6R2ERlV</span></span> <span class="giallo-l"><span>gPiUWOPatVkt7+Bs3h5Ramxh7XjBOXeulmCpGSynXNcpZ/06+vofGi/2MlpQZNhH</span></span> <span class="giallo-l"><span>Ao8eayMp6FcvNucIpUndo1X8dKMv3Y26ZQIDAQAB</span></span> <span class="giallo-l"><span>-----END RSA PUBLIC KEY-----</span></span></code></pre> <p>You can’t simply copy-paste this in an <em>authorized_keys</em> file. Hopefully you can easily convert the public key from a format to another. This is done by I-do-about-anything-and-everything command, aka <code>ssh-keygen</code>:</p> <pre class="giallo z-code" ><code data-lang="plain"><span class="giallo-l"><span>$ ssh-keygen -i -m &lt;format&gt; -f input_key.pub &gt; output_key.pub</span></span></code></pre> <p><code>-m</code> specify the input key format among <em>RFC4716</em> (the format used by PuTTY, this is the default if <code>-m</code> isn’t specified), <em>PKCS8</em> and <em>PEM</em>.</p>