Types of Cryptanalysis attacks

1. Types of Cryptanalysis attacks 3. Chosen-plaintext attack The cryptanalyst (attacker) not only has access to the cipher text and associated plain text for several message. But be also chooses the plain text that gets encrypted, so his job is to divide the plaintext into several blocks by which he can deduce the key (or keys) used to encrypt the message or an algorithm to decrypt any new message encrypted with the same key (or keys)

2. Chosen-plaintext attack

3. Types of Cryptanalysis attacks 4. Adaptive-chosen-plaintext attack This is a special case of a chosen-plaintext attack. Note only can the cryptanalyst (attacker) choose the plaintext that is encrypted, but he can also modify his choice based on the result of pervious encryption

4. Types of Cryptanalysis attacks • 5. Chosen-Cipher text attack • The cryptanalyst (attacker) here can choose a set of encrypted messages and try to decrypt them to access the plaintext text with the key. This method is used to attack cryptographic systems using two keys K1, K2 that is known as Public-Key algorithm, and sometimes attack cryptographic systems using one key which is known as One-Key algorithm.

5. . Chosen-Cipher text attack

6. Types of Cryptanalysis attacks • 6. Chosen-key attack • Here the cryptanalyst (attacker) has some information that has to do with different keys and tries to reach the desired key

7. Types of Cryptanalysis attacks 7 -Rubber-hose cryptanalysis • Is the use of bribery, extortion and threat to access the key. • Note that, the methods from 1 to 4 assume that the cryptanalyst has complete knowledge of the encryption algorithm used

8. Traditional or Classic Cipher • Traditional ciphers used two techniques for hiding information from intruder : • Transposition cipher • Substitution cipher

9. Transposition Ciphers • A transposition cipher does not substitute one symbol for another, instead it changes the location of the symbols. A symbol in the first position of the plaintext may appear in the tenth position of the cipher text, while a symbol in the eighth position in the plaintext may appear in the first position of the cipher text. In other words, a transposition cipher reorders (transposes) the symbols • Note • A transposition cipher reorders symbols.