I need to install a couple of packages.
pkg install openssl-tool pkg install openssh
Set up your ssh key. I use passphrases.
To have gitlab.com in your git config be recognised by ssh, and to use the particular key for gitlab:
Host gitlab.com HostName gitlab.com User git Port 22 IdentityFile ~/.ssh/gitlab
To make sure you don't have to keep entering it:
Host * AddKeysToAgent yes
And at the start of new Termux session:
eval $(ssh-agent) ssh-add