“What was that? We need to set up the secrets in our new repository, so our CI can run? No problem, I can do it; just copy-paste the secrets in our private chat!” 
I was going through this exact situation, when @0x12b showed me a cool way to share the secret – so cool, in fact, that I’m writing this short post about it 
You can (and should) encrypt the secret, but it’s tedious, because you have to:
- find the public key of the person you want to share it with;
- remember how to encrypt something.
There’s a solution to both problems:
curl https://github.com/<username>.keys, to get someone’s GitHub public key from their username;age, to encrypt/decrypt the secret.
All you have to do is encrypt the file:
curl https://github.com/lucabello.keys | age -R - <secret-file> > secret-file.age
You can also encrypt the file for more recipients at the same time:
gh_keys=$(for gh_user in lucabello <someone-else>; do curl https://github.com/$gh_user.keys; done); echo $gh_keys | age -R - <secret-file> > secret-file.age
Now you can send secret-file.age via Matrix to your colleagues; they can decrypt it by passing their private key to age:
age --decrypt -i <private-key> secret-file.age
Hope this helps! 