Cloudture
Cloudture is encryption using xor and one-time pads
...I suggest to use the real, possibly subliminal, message as the key to encode your "secret" messages, with the full expectation that if the attacker uses enough resources, he will be able to read the "secret" message, IF HE HAS STORED THE KEY IN HIS DATABASES.
You could, for example, use a copy of the movie "1984" as the source for key.
To make sure that e.g. the entire movie is stored eventually, the program allows you to specify an offset into the key source.