II. Information Entropy & Cryptography (Brute Force and Cryptanalysis)

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)

Information Entropy (Simplified)

Dr. C. Shannon Information Entropy The information entropy (a.k.a Shannon’s Entropy) describes the disorder of the system. Let’s consider coin flipping system, where there are two possibilities for output such as head or tail. Hence, we may consider the system with 1-bit information (e.g. “0” for head and “1” for tail) and there is %50 chance … Continue reading Information Entropy (Simplified)

I. Cryptography: 101

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