Cryptographic Attacks

Types of Cryptographic Attacks
Eric Conrad

Types of Cryptographic Attacks
Introduction
Cryptographic attacks are designed to subvert the security of cryptographic algorithms, and they are used to attempt to decrypt data without prior access to a key. They are part of Cryptanalysis, which is the art of deciphering encrypted data. Cryptanalysis and
Cryptography (the art of creating hidden writing, or ciphers) form the science of
Cryptology.

Cryptographic Attack Methods
There are six related cryptographic attack methods, including three plaintext-based methods and three ciphertext-based methods:

These methods are used as the foundation of cryptographic attacks.

Known Plaintext and Ciphertext-Only Attacks
A known plaintext attack is an attack where a cryptanalyst has access to a plaintext and the corresponding ciphertext and seeks to discover a correlation between the two.
A ciphertext-only attack is an attack where a cryptanalyst has access to a ciphertext but does not have access to corresponding plaintext. With simple ciphers, such as the Caesar
Cipher, frequency analysis can be used to break the cipher.

Chosen Plaintext and Chosen Ciphertext Attacks
A chosen plaintext attack is an attack where a cryptanalyst can encrypt a plaintext of his choosing and study the resulting ciphertext. This is most common against asymmetric cryptography, where a cryptanalyst has access to a public key.
A chosen ciphertext attack is an attack where a cryptanalyst chooses a ciphertext and attempts to find a matching plaintext. This can be done with a decryption oracle (a machine that decrypts without exposing the key). This is also often performed on attacks versus public key encryption; it begins with a ciphertext and searches for matching publicly-posted plaintext data.

Adaptive Chosen Plaintext and Adaptive Chosen Ciphertext Attacks
In both adaptive attacks, a cryptanalyst chooses further plaintexts or ciphertexts (adapts the attack) based