Types of cryptanalysis attack

• Known-Plaintext Analysis (KPA) requires access to some or all of the plaintext of the encrypted information. The plaintext is not computationally tagged, specially formatted, or written in code. The analyst's goal is to examine the known plaintext to determine the key used to encrypt the message. Then they use the key to decrypt the encoded information.
• Chosen-Plaintext Analysis (CPA) requires that the attacker knows the encryption algorithm or has access to the device used to do the encryption. The analyst can encrypt one block of chosen plaintext with the targeted algorithm to get information about the key. Once the analyst obtains the key, they can decrypt and use sensitive information.
• Ciphertext-Only Analysis (COA) requires access to one or more encrypted messages. No information is needed about the plaintext data, the algorithm, or data about the cryptographic key. Intelligence agencies face this challenge when intercepting encrypted communications with no key.
• Adaptive Chosen-Plaintext Attack (ACPA) is similar to a chosen-plaintext attack. Unlike a CPA, it can use smaller lines of plaintext to receive its encrypted ciphertext and then crack the encryption code using the ciphertext.
• Meddler-in-the-Middle (MITM) uses cryptanalysts to insert a meddler between two communication devices or applications to exchange their keys for secure communication. The meddler replies as the user and then performs a key exchange with each party. The users or systems think they communicate with each other, not the meddler. These attacks allow the meddler to obtain login credentials and other sensitive information.

Results from a cryptanalysis attack

• Instance deduction where the attacker discovers additional plain or cipher text. While the key isn’t found to break the code, the additional plaintext or ciphertext can be used to cause problems or continue attacks.
• Information deduction where the attacker ****obtains some information about plain or cipher text not previously known. The additional information can lead to more information about the encryption key.
• Distinguishing algorithm where the attacker can distinguish the encryption algorithm from a random alteration. This information reveals clues about the encryption algorithm and can lead to more significant breaks.
• Global deduction where the attacker finds an algorithm that is functionally equivalent to the one used in the key. This algorithm is then used to decrypt all information and messages.
• Total break where the attacker can gain the entire key. With the entire key, the attacker can decrypt all messages and information.