A method and apparatus for generating a group of non-repetitive, difficult-to-guess character sets is disclosed. The method includes (a) generating a request for a character set by a client of a character-generating server, (b) sending the request to the character-generating server, (c) generating a pseudo random number required by the character generator; (d) sending the pseudo random number to the character generator; (e) generating a character for the character set by the character generator, (f) sending the character set along with a related key to the client; (g) sending the character set along with the related key to a target server, (h) sending related key to the character-generating server by the target server; (i) re-creating the character set from the related key by the target server; and (j) sending the character set along with the related key to the target server.