One who frobs bits. Ever read the man page for frob in glibc? A bitfrobber is one who encrypts data or otherwise obfuscates information so only the intended party can read the information. Bitfrobbers may or may not be good at what they do; some write strong crypto packages (such as GNU Privacy Guard or PGP) and some merely induce bit rot. One of the defining characteristics of a bitfrobber is the difficulty in finding a file on his/her system that both contains "txt" in the filename, AND has ASCII printable characters in it.