Quantum cryptography actually has much stronger ties to information theory than the cryptography we're talking about here. There's also quantum-resistant cryptography, which aims to re-create the existing systems we have in ways that are resistant to quantum computers.

The algorithms most endangered by the ever-looming threat of generalised quantum computing are actually our most popular public key cryptography schemes. Symmetric cryptography (where the key is the same on both sides; the block ciphers and stream ciphers we've been learning about) is actually mostly safe from that stuff.

It's not steganography, but if I can fit it in, I'd love to do a post on steganography! Maybe I'll do it as a separate post. If I do I'll credit you for giving me the idea!