Here’s a good one I learned the other day –
Let’s say you’ve got one of those standard spinny-dial combination locks locking up your tool shed or junior high school locker. Not the kind you set yourself, but rather the kind that comes with a pre-set combination – say, 24 - 3 - 18. Particularly if it’s a lock you rarely use, you’re almost sure to forget the combo. Some people get around this by just leaving the little combo sticker on the back of the lock. Somewhat defeats the purpose of the lock, though. Here’s a neat trick. Take a number that you will remember. It should include at least three numbers within it. Birthdays work well. You can use this as the key to encrypt your combination and then write the encrypted number on the back of the lock.
Combo: 24 - 3 - 18
Birthday: 4 / 17 / 72
Add each number together and write it on the back of the lock: 28 - 20 - 90
When you need to open the lock, just subtract your birthday. Neat, huh? Anyone else got any tricks like this?