In which type of attack the attacker tries to figure out the key used for encryption?
What is cryptanalysis?Cryptanalysis is the study of ciphertext, ciphers and cryptosystems with the aim of understanding how they work and finding and improving techniques for defeating or weakening them. For example, cryptanalysts seek to decrypt ciphertexts without knowledge of the plaintext source, encryption key or the algorithm used to encrypt it; cryptanalysts also target secure hashing, digital signatures and other cryptographic algorithms. Show
How does cryptanalysis work?While the objective of cryptanalysis is to find weaknesses in or otherwise defeat cryptographic algorithms, cryptanalysts' research results are used by cryptographers to improve and strengthen or replace flawed algorithms. Both cryptanalysis, which focuses on deciphering encrypted data, and cryptography, which focuses on creating and improving encryption ciphers and other algorithms, are aspects of cryptology, the mathematical study of codes, ciphers and related algorithms. Researchers may discover methods of attack that completely break an encryption algorithm, which means that ciphertext encrypted with that algorithm can be decrypted trivially without access to the encryption key. More often, cryptanalytic results uncover weaknesses in the design or implementation of the algorithm, which can reduce the number of keys that need to be tried on the target ciphertext. For example, a cipher with a 128 bit encryption key can have 2128 (or 340,282,366,920,938,463,463,374,607,431,768,211,456) unique keys; on average, a brute force attack against that cipher will succeed only after trying half of those unique keys. If cryptanalysis of the cipher reveals an attack that can reduce the number of trials needed to 240 (or just 1,099,511,627,776) different keys, then the algorithm has been weakened significantly, to the point that a brute-force attack would be practical with commercial off-the-shelf systems. Who uses cryptanalysis?Cryptanalysis is practiced by a broad range of organizations, including governments aiming to decipher other nations' confidential communications; companies developing security products that employ cryptanalysts to test their security features; and hackers, crackers, independent researchers and academicians who search for weaknesses in cryptographic protocols and algorithms. It is this constant battle between cryptographers trying to secure information and cryptanalysts trying to break cryptosystems that moves the entire body of cryptology knowledge forward. Cryptanalysis techniques and attacksThere are many different types of cryptanalysis attacks and techniques, which vary depending on how much information the analyst has about the ciphertext being analyzed. Some cryptanalytic methods include:
Other types of cryptanalytic attacks can include techniques for convincing individuals to reveal their passwords or encryption keys, developing Trojan horse programs that steal secret keys from victims' computers and send them back to the cryptanalyst, or tricking a victim into using a weakened cryptosystem. Side-channel attacks have also been known as timing or differential power analysis. These attacks came to wide notice in the late 1990s when cryptographer Paul Kocher was publishing results of his research into timing attacks and differential power analysis attacks on Diffie-Hellman, RSA, Digital Signature Standard (DSS) and other cryptosystems, especially against implementations on smart cards. Tools for cryptanalysisBecause cryptanalysis is primarily a mathematical subject, the tools for doing cryptanalysis are in many cases described in academic research papers. However, there are many tools and other resources available for those interested in learning more about doing cryptanalysis. Some of them include:
Cryptanalysts commonly use many other data security tools including network sniffers and password cracking software, though it is not unusual for cryptanalytic researchers to create their own custom tools for specific tasks and challenges. Requirements and responsibilities for cryptanalystsA cryptanalyst's duties may include developing algorithms, ciphers and security systems to encrypt sensitive information and data as well as analyzing and decrypting different types of hidden information, including encrypted data, cipher texts and telecommunications protocols, in cryptographic security systems. Government agencies as well as private sector companies hire cryptanalysts to ensure their networks are secure and sensitive data transmitted through their computer networks is encrypted. Other duties that cryptanalysts may be responsible for include:
Individuals planning to pursue a career in cryptanalysis are advised to obtain a bachelor's degree in computer science, computer engineering, mathematics or a related field; some organizations will consider hiring individuals without a technical degree if they have extensive training and prior work experience in the field. A Master of Science degree is also strongly recommended, unless the candidate already has a bachelor's degree in mathematics and computer science. The strongest candidates will have a doctoral degree in mathematics or computer science with a focus on cryptography. This was last updated in October 2021 Continue Reading About cryptanalysis
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What type of attack is encryption?A cryptographic attack is a method used by hackers to target cryptographic solutions like ciphertext, encryption keys, etc.
In what type of attack does an attacker try from several encrypted messages to figure out the key used in the encryption process?In the 'cipher-only' attack, the attacker knows the ciphertext of various messages which have been encrypted using the same encryption algorithm. The attacker's challenge is to figure the 'key' which can then be used to decrypt all messages.
What is known cipher attack?In cryptography, a ciphertext-only attack (COA) or known ciphertext attack is an attack model for cryptanalysis where the attacker is assumed to have access only to a set of ciphertexts.
What is cryptanalysis and brute force attack?In cryptanalysis, a brute force attack is a method of defeating a cryptographic scheme by trying a large number of possibilities; for example, exhaustively working through all possible keys in order to decrypt a message.
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