Chapter 7: Running and Concealment Ciphers:

• Running Key Cipher:
• Can use a key that does not require an electronic algorithm and bit alternation.
• Uses components in the physical world.
• Example:
•  An algorithm that is a set of books agreed upon by the sender and receiver. The key in this cipher could be a book page, line number, and column count.
• Concealment Cipher:
• This type of cipher is a message within a message.
• Example:
• Suppose it was agreed upon to have a key with every third word within a message. If a secret message was sent that read, “The saying, ‘The time is right’ is now cow language, so is not a dead subject.” Because the key is every third word, the secret message within the message would be “The right cow is dead.”