Glowing is not cryptographic jargon. It's a word used years ago by the developer of TempleOS in a livestream to describe CIA operators. He said he could tell who was CIA because they would glow in the dark. Users of the 4chan technology board witnessed this and it became a meme.

To say something glows means to suggest the US three letter agencies are interfering with it. If some cryptography glows, it means it's been compromised by US authorities. Glowies are the operators themselves.