Claude Shannon set the limit for perfect secrecy
Shannon showed that perfect secrecy is possible only when the secret key is at least as long, in binary digits, as the information being encrypted. The one-time pad meets this requirement.
Why perfect secrecy requires a key as long as the message
Shannon showed that perfect secrecy is possible only when the secret key is at least as long, in binary digits, as the information being encrypted. The one-time pad meets this requirement.