The Key Distribution Problem
| Games : Codes And Ciphers The key distribution problem is something that seems to create an insoluble chicken and egg situation. In order to secure a communication, we need to agree the key that we will use. Once we have the key we can both decrypt and encrypt any piece of arbitrary data. As long as the key is safe and we use something sensible and of a suitable length it is somewhere between very hard and impossible for anyone to crack our code. Clearly therefore the cipher is as secure as its key. But how do we communicate that key? If I send it to you unsecurely then there is a great risk of it being intercepted rendering our communication useless. But if I encrypt the key to send it to you securely, then I need to use some form of encryption to send it. In other words, sending a key unsecurely compromises the security of code, but to send it securely requires an existing code and therefore key to have been used. So to encrypt a secret we first need to have shared a secret about the key. This is the key distribution problem, and has caused real problems throughout history. The interception of a key has caused countless ciphers to be transparent to authorities of all sorts. And distribution has been a logistical nightmare - if a key code changed daily in a battle then it would have to be communicated daily to everyone involved in the communications and they all had to keep in sync. It seemed there was no solution to the key distribution problem, but it turned out that there was. It might be interesting to see if you can think of a method of solving the key distribution problem. In other words, you need to be able to establish a method of having someone encrypt a message and send it to you such that only you can decrypt the message, without there being any communication of the key to use to decrypt the message!
 Questions about code book:
|
|
Tweet this!
