Cryptography came from Spartans Military (Greeks)
CryptoGraphy
Kryptos means Hidden
Gráphō means writting
Transposition Method
5th century BC – Spartan generals exchanged secret messages by wrapping narrow ribbons of parchment around a cylindrical staff known as a scytale, then transcribing their messages on the papyrus. The messages could only be read when the papyrus was re-wound around a scytale of the same thickness.
The diameter of the cylinder , therefore is the key
Substitution Method
The scytale method was used by the government officials of Sprta to communicate with their military officer.
It was not until a couple of centuries later that another popular encryption method arises: The ceasar cipher, named after Julius Caesar.
CODE BOOK
Each Letter is replaced by only one cipher symbol
MONO-ALPHABETIC
Cryptanalysis Era
The problem so far for Cryptography
There is no distinguish between cryptographic system and key because system were so simple (code book is the key, and the system is mapping plain text to cipher)
All the expense is making the code book and making the secret piece.
Diffie Hellman
RSA Asymmetric Encryption
(Public key and Private Key)
THE END
Copy rights : All screenshots are taken from my own presentation that i did upon graduation.
Pingback: Cryptography Fundamentals | Ammar Hasayen - Blog