Category: § Science

Before getting started with Block Cipher, digital computer communications based on bits, where 1 byte equals 8 bits. For instance, the word cryptoquantus consist of 13 characters (byte), so it equals to 8x13 = 104 bits . ASCII (American Standard Code for Information Interchange) is an encoding representing each typed character by a number, where … Continue reading IV. Block Cipher & DES

First Transposition Cipher in History It was firstly used by Greeks and Spartans for military secrecy, 15th Century B.C. as Scytale Cipher. A Scytale Cipher is simply a wooden stick around which a strip of leather is wrapped. Sender writes the message along the length of the stick and unwinds the strip, where letters are … Continue reading III. Transposition Cipher

Brute Force Attack As the name suggests, "Brute Force Attack", the process is based on testing all possible keys until find the correct key. Let's consider that the attacker finds out the correct key after trials. We have 4 keys such as, k_1-(00), k_2-(01), k_3-(10), k_4-(11) where information entropy of the system is 2 bits … Continue reading II. Information Entropy & Cryptography (Brute Force and Cryptanalysis)

Cryptography Terminology Cryptography, the study of encryption and decryption techniques. Cryptanalysis, codebreaking and deciphering ciphertext without the key. Cryptology, the field of cryptography and cryptology. Alice, Bob & Eve Framework Alice sends a message to Bob and Eve (stands for eaves dropper) wants to get the message. Here; there are, classical (e.g. Caesar cipher) and modern … Continue reading I. Cryptography: 101