Moving private keys securely between devices

private_transfer.md

There is no transfer method more secure than using a physical USB storage to move the private key. However, often connecting physical devices is a barrier and at other times is an opposite wind. So, we'll create a simple HTTP server over a private (home) network and use that for the transfer.

Origin

Let us first export the GPG private and public keys:

gpg --output private.key --armor --export-secret-keys [email protected]
gpg --output public.key --armor --export [email protected]

Most machines today will have at least a primitive version of python installed.

cd ~/
python3 -m http.server

Also, we'll need to know the IP address of the origin machine as,

ipconfig getifaddr en0 # considering it's wireless

This gives us (let's say) 1.2.3.4.

Destination

We open up a browser or curl 1.2.3.4 and download the following files:

• ~/.gnupg/private.key
• ~/.gnupg/public.key
• ~/.ssh/keys/personal.pem

And then move then appropriately to the location as required:

cp ~/Downloads/*.pem ~/.ssh/keys/

A file downloaded from web doesn't have correct permissions for being a SSH key, hence we need to fix the permissions as well:

chmod 400 ~/.ssh/keys/*.pem