Topic: Authenticity check issue.
To verify the authenticity of iso they suggest to download the key using the mit.edu servers, but this server is always busy (or down)
gpg --keyserver pgp.mit.edu --recv-key "C92B AA71 3B8D 53D3 CAE6 3FC9 E697 4752 F970 4456"
I suggest to change the server in the hyperbola guide, for example, with keyserver.ubuntu.com:
gpg --keyserver keyserver.ubuntu.com --recv-key "C92B AA71 3B8D 53D3 CAE6 3FC9 E697 4752 F970 4456"