Cryptographic hash functionA cryptographic hash function (CHF) is a hash algorithm (a map of an arbitrary binary string to a binary string with a fixed size of n{\displaystyle n} bits) that has special properties desirable for cryptographic applications. Hashing is a one-directional mathematical operation which is quick to calculate, yet hard to reverse. Common uses include password storage and digital signatures.
Brute-force attackIn cryptography, a brute-force attack or exhaustive key search is a cryptanalytic attack that consists of an attacker submitting many possible keys or passwords with the hope of eventually guessing correctly. This strategy can theoretically be used to break any form of encryption that is not information-theoretically secure. However, in a properly designed cryptosystem the chance of successfully guessing the key is negligible.Collision attackIn cryptography, a collision attack on a cryptographic hash tries to find two inputs producing the same hash value, i.e. a hash collision. This is in contrast to a preimage attack where a specific target hash value is specified. There are roughly two types of collision attacks: Classical collision attack Find two different messages m1 and m2 such that hash(m1) = hash(m2).
Time complexityIn theoretical computer science, the time complexity is the computational complexity that describes the amount of computer time it takes to run an algorithm. Time complexity is commonly estimated by counting the number of elementary operations performed by the algorithm, supposing that each elementary operation takes a fixed amount of time to perform.
Collision resistanceIn cryptography, collision resistance is a property of cryptographic hash functions (CHFs): a hash function H is collision-resistant if it is hard to find two inputs that hash to the same output; that is, two inputs a and b where a ≠ b but H(a) = H(b). The pigeonhole principle means that any hash function with more inputs than outputs will necessarily have such collisions; the harder they are to find, the more cryptographically secure the hash function is.
CryptanalysisCryptanalysis (from Greekkryptós'hidden' and analýein'to analyze') refers to the process of analyzing information systems in order to understand hidden aspects of the systems. Cryptanalysis is used to breach cryptographic security systems and gain access to the contents of encrypted messages, even if the cryptographic key is unknown.
MD5The MD5 message-digest algorithm is a widely used hash function producing a 128-bit hash value. MD5 was designed by Ronald Rivest in 1991 to replace an earlier hash function MD4, and was specified in 1992 as RFC 1321. MD5 can be used as a checksum to verify data integrity against unintentional corruption. Historically it was widely used as a cryptographic hash function; however it has been found to suffer from extensive vulnerabilities.
SHA-1In cryptography, SHA-1 (Secure Hash Algorithm 1) is a hash function which takes an input and produces a 160-bit (20-byte) hash value known as a message digest – typically rendered as 40 hexadecimal digits. It was designed by the United States National Security Agency, and is a U.S. Federal Information Processing Standard. The algorithm has been cryptographically broken but is still widely used.CryptographyPractice and study of secure communication techniquesLorenz cipher machine, used in World War II to encrypt communications of the German High CommandCryptography, or cryptology, is the practice and study of techniques for secure communication in the presence of adversarial behavior. More generally, cryptography is about constructing and analyzing protocols that prevent third parties or the public from reading private messages.
MessageA message is a unit of communication that conveys information from a sender to a receiver. It can be transmitted through various forms, such as spoken or written words, signals, or electronic data, and can range from simple instructions to complex information. The consumption of the message relies on how the recipient interprets the message, there are times where the recipient contradicts the intention of the message which results in a boomerang effect.
Image (mathematics)Set of the values of a functionFor the function that maps a Person to their Favorite Food, the image of Gabriela is Apple. The preimage of Apple is the set {Gabriela, Maryam}. The preimage of Fish is the empty set. The image of the subset {Richard, Maryam} is {Rice, Apple}.
Quantum computingComputer hardware technology that uses quantum mechanicsIBM quantum computer demo at ITUWTSA 2024 in DelhiBloch sphere representation of a qubit. The state |ψ⟩=α|0⟩+β|1⟩ is a point on the surface of the sphere, partway between the poles, |0⟩ and |1⟩.A quantum computer is a computer that represents and processes information using quantum states. Quantum computations exploit phenomena such as superposition, interference, and entanglement.*As an Amazon Associate I earn from qualifying purchases.