This doesn't work for encryption, though. You'd need a cryptosystem where it's possible to encrypt a message with H(x) such that it can only (efficiently) be decrypted given x, for a hash function H. To the best of my knowledge, no such hash function is known.
Note however that you would need a nonce / salt transmitted with each message because otherwise decrypting messages encrypted with the same key would just be as easy as XORing them!
Snuffle is symmetric key encryption, and yes, it's a well-known construction. However, you previously suggested that an asymmetric encryption scheme (with public and private keys) could be constructed using a hash.
