Well Number seven encrypted data is only as secure as its decryption key.
This principle is as obvious as it is overlooked.
Some people encrypt data or passwords using a specialised program which requires a password to start
the encryption process and then they store the decryption password on the same computer.
This does not hinder the attack in any way.
You have to protect the decryption key.
The strength of encryption measures comes from the fact that it allows you to focus on protection of
a relatively small element the key rather than the whole body of data.
Similarly if you keep your car keys safe you don't have to worry about someone driving off with your
car.
But if you lock the car door and leave the keys on the car roof it would hardly protect the car from
being stolen.
This is a perfect metaphor for encryption measures.
The Second Law is still valid.