Security Encyclopedia

Fernando J. Corbató

Fernando J. Corbató was an American pioneer in the field of computer science who is best known as being the father of the password.

Corbató was a physicist whose interests evolved into what would become a burgeoning field in its own right, computer science. As computers grew in their development and dependability, a use case for one of Corbató’s own creations, the Compatible Time-Sharing System (CTSS), emerged. How to securely and practically expand the user population became immediately important. Toward this end Corbató conceived and applied the concept of a password — familiar in the physical world — to computers. Upon his death in 2019 the Massachusetts Institute of Technology, where his work was done at the time, credited Corbató with “drastically expanding the usefulness” of computers.

In addition to the CTSS, while at MIT’s Computation Center from 1963-66, Corbató developed a Multiplexed Information and Computing Service (Multics) that built upon the CTSS’s success and could be deployed and useful to a larger population. Also while there, he did foundational work on the operating system UNIX.


“Fernando J. Corbató applied the use of a closely-held mutual secret — the password — to the novel challenge of how to manage multiple users of a computer. This paved the way for expanded uses of computers across the enterprise and later, with the emergence or the web, large user populations.”