Of no use to one, yet absolute bliss to two.
The small boy gets it for nothing.
The young man has to lie or work for it.
The old man has to buy it.
The baby's right, the lover's privilege, the hypocrite's mask.
To the young girl, faith;
To the married woman, hope;
To the old maid, charity.
What am I?
Suppose you want to send in the mail a valuable object to a friend. You have a box which is big enough to hold the object. The box has a locking ring which is large enough to have a lock attached and you have several locks with keys. However, your friend does not have the key to any lock that you have. You cannot send the key in an unlocked box since it may be stolen or copied. How do you send the valuable object, locked, to your friend - so it may be opened by your friend?
Send the box with valuable object and a lock attached and locked. Your friend attaches his or her own lock and sends the box back to you. You remove your lock and send it back to your friend. Your friend may then remove the lock she or he put on and open the box.
Search: Man-in-the-middle attack
