A method of operating an electronic device includes generating scramble control codes. The scramble codes are generated by generating a random number, shifting the random number to produce a shifted random number, generating control signals by selecting different subsets of the shifted random number, and generating scramble control words by selecting different subsets of the random number based upon the control signals. The method further includes receiving a password comprised of sub-words and scrambling those sub-words according to the scramble control codes, retrieving a verification word comprised of sub-words and scrambling those sub-words according to the scramble control codes, and comparing the scrambled sub-words of the password to the scrambled sub-words of the verification word to thereby authenticate an external device that provided the password.