Over the years, there have been a few noteworthy binary protectors that were released both publicly and from the underground scene. I will discuss some of the protectors for Linux and give a synopsis of the various features.
DacryFile is the earliest binary protector that I am aware of for Linux (https://github.com/packz/binary-encryption/tree/master/binary-encryption/dacryfile). This protector is simple but nonetheless clever and works very similarly to ELF parasite infection from a virus. In many protectors, the stub wraps around the encrypted binary, but in the case of DacryFile, the stub is just a simple decryption routine that is injected into the binary that is to be protected.