Keep in mind that Excel generates pseudo-random numbers and not truly random numbers. Verify that your version of Excel (2000 or better) uses the system clock as the random seed (the sequence should change each time you open the spreadsheet). I also highly recommend refreshing the sequence with a new random seed (F9 or delete an empty cell) more than once while choosing password characters; consider the following examples. For adding 10 characters to a password: open the spreadsheet, write down characters 1-5, refresh the random seed, and write down characters 6-10. For adding 20 characters to a password: open the spreadsheet, write down characters 1-10, refresh the random seed, and write down characters 1-10 again. The random seed could (probably should) also be refreshed for each individual password character for maximum randomness and maximum strength passwords (F9 or delete an empty cell for each new password character used).
StrongRandomPasswordGenerator.xls is an Excel .xls spreadsheet that uses the RAND() function to create a sequence of random characters for strong passwords. There are traditionally two security problems with passwords: 1) too simple or short and 2) written next to the computer. Both of these potential problems can be overcome by the user. Many organizations mandate that passwords may not be written down, which tends to impact password complexity. Manyrecentarticles suggest that writing down passwords actually increases security, so they can be very complex and unique; just do not write them on a sticky note on your monitor or keyboard.
The spreadsheet generates a sequence of random password characters from ASCII 33 ! to ASCII 126 ~, which encompasses all uppercase, lowercase, numbers, and special characters available on most US keyboards. All or part of the randomly generated characters can be used in a new password or to help strengthen an existing password. The spreadsheet will generate a new sequence of characters every time it is loaded and every time a cell is changed; the sequence is never saved in the spreadsheet, unless it is copied and pasted as text.
Traditionally, weak passwords use 8 characters or less and only use lowercase letters, which is only 26 possible characters. Passwords should use a combination of uppercase, lowercase, numbers, and special characters whenever possible, which is about 94 possible characters on most US keyboards.