I think it is just overthinking. Alice and Bob are a couple, and like most couples, there is a woman and a man. The names are short, memorable, and start with

I think it is just overthinking. Alice and Bob are a couple, and like most couples, there is a woman and a man. The names are short, memorable, and start with A and B. It is natural to choose a couple, as couples often have private conversations. Charlie, probably from the NATO/ICAO alphabet. Eve, like eavesdropper. Malory, like malicious. Trent, like trust. If there is something special about Alice, I will be more tempted to think about the most famous Alice, the one in Wonderland. Besides the nice story, Lewis Carrol, author of "Alice's Adventures in Wonderland", real name Charles Dodgson was also a mathematician, and he dabbed in cryptography.