Growth Capitalism

Back To Introduction
Claude Shannon

1. The encryption keys must be random numbers of uniform distribution.

2. The keys must be shared in absolute secrecy by the sender and receiver.

3. Any key encrypting a message must be as at least as long as that message.

4. Any key used to encrypt a message must not be reused.

The most famous encryption algorithm having all of these characteristics is the

Information conveyed over the Internet is represented by numbers whose digits include only 0 and 1. Each digit is called a

The purpose of encryption is to create as much uncertainty as possible as to which character was present in the message before it was encrypted. The one-time pad does this by adding (without carry) a separate and randomly chosen bit to each bit in the message. Like the regular operations of adding or subtracting,

A B Sum ------------------- 0 0 0 0 1 1 1 0 1 1 1 0

Notice that the sum of 1 and 1 in binary is 10, but the carry bit is not included in the sum by the add-without-carry operation. Only the least significant bit of the sum is used (in this case, 0).

For a more thorough explanation see Perfect Encryption, by James Adrian.

1. "Claude Elwood Shannon - Collected Papers" edited by N. J. A. Sloane and Aaron D. Wyner.