I think perhaps you have a very different idea from @Osiris (and myself) of what "security by obscurity" is.
An unpublished (or proprietary) encryption algorithm is security by obscurity.
A secret equation (or the application of some esoteric concept) is security by obscurity.
Giving every thing and function in the human body a Latin term is (job) security by obscurity.
Understanding the RSA algorithm doesn't increase your ability to determine my private key. Thus, RSA is NOT security by obscurity.
There is no obscurity in not responding with sensitive content via HTTP on any port, which by definition is a form of security WITHOUT obscurity.
Steganography is not cryptography.