Robert Llewellyn Robert Llewellyn Robert Llewellyn (born 10 March 1956 in Northampton, Northamptonshire) is a British actor, comedian and writer. He plays the mechanoid Kryten in the TV sci-fi sitcom "Red Dwarf" and formerly presented the TV engineering gameshow "Scrapheap Challenge". He also presents a YouTube series, "Fully Charged". Llewellyn's first foray into the world of show business started out as a hobby, organising a few amateur cabaret evenings in a riverside warehouse overlooking Tower Bridge in London. The shows were a great success and he eventually helped form an alternative comedy theatre group called the Joeys. Within six months he had
Challenge–response authentication Challenge–response authentication In computer security, challenge–response authentication is a family of protocols in which one party presents a question ("challenge") and another party must provide a valid answer ("response") to be authenticated. The simplest example of a challenge–response protocol is password authentication, where the challenge is asking for the password and the valid response is the correct password. Clearly an adversary who can eavesdrop on a password authentication can then authenticate itself in the same way. One solution is to issue multiple passwords, each of them marked with an identifier. The verifier can ask for any of the passwords, and