Introduction to Cryptography
Hello everybody!Â
I apologize for not having written but today, Iâll start new series of article about cryptography.Â
On the next lesson, tell you: How work new cryptography algorithms? I try give you any information about cryptography at nowadays.
Today I will tell you historical information about Cryptography.
1. Early cryptography
Cryptography alrgorithm (cipher):Â
100-1 CE - Notable Roman ciphers such as the Caesar cipher.
It is very simple - it is just shifting an alphabet.
And reverse cipher
How it work?
The action of a Caesar cipher is to replace each plaintext letter with a different one a fixed number of places down the alphabet. The cipher illustrated here uses a left shift of three, so that (for example) each occurrence of E in the plaintext becomes B in the ciphertext.
Example Encrypt text with a shift (key) of 3 - âTESTâ in result Iâll have âWHVWâ (Try do it)
Read more: Caesar cipher (external site).
2. Medieval cryptography
Let us turn to Wikipedia for more information:
"David Kahn notes in The Codebreakers that modern cryptology originated among the Arabs, the first people to systematically document the methods of cryptanalysis"
And also, mentioned textual analysis of the Qur'an which led to the invention of the frequency-analysis technique for breaking monoalphabetic substitution ciphers, by Al-Kindi, an Arab mathematician, sometime around AD 800.
"It proved the most fundamental cryptanalytic advance until WWII."
Also, Al-Kindi wrote a book on cryptography "Manuscript for the Deciphering Cryptographic Messages", in which he described the first cryptanalysis techniques, including some for polyalphabetic ciphers, where gave the first descriptions on frequency analysis.
3. Modern cryptography
3.1 1845: Morse Code â Represention by code signal (United States) Â
Thank You!
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