So we are getting into information theory, but any cryptographic protocol that generates cyphertext that is distinguishable from random noise is easier to crack than the stated security level. So a 128 bit encryption protocol, if the cyphertext can be found to have any data in it that can be demonstrated to be non random, the protocol does not have 128 bits of security.
All good encryption protocols will always create cyphertext that is indistinguishable from random noise, this is not an endorsement of any "good" protocols, but rather a general statement about encryption which must be true. You should not be able to infer anything about the data encoded in the cyphertext without the key.
