This should not be possible, or must be considered crypto analysis right away. An encryption is build by design such that it is not possible to obtain any knowl

This should not be possible, or must be considered crypto analysis right away. An encryption is build by design such that it is not possible to obtain any knowledge of the content of the encrypted message (or series of consecutive encrypted messages). If I can make some assumptions about an encrypted message (i.e. its content, the authors interesets etc.) the encryption is flawed by definition.