text encryption

Posted by tris on February 01, 2005 at 12:30:04:

hey,

i am writing a program in delphi where a voter can vote for
their favourite colour, and the voters id gets saved into a
seperate text file to the vote text file. i am trying to make
it secure so if anyone looks at this voted.txt they will not
see the names of the people who voted. and hence i want to
encrypt the names (and decrypt to check they havent voted
twice).

does anyone have any ideas of how i can do this?

thanks
tris