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XDH Assumption
The external Diffie–Hellman (XDH) assumption is a computational hardness assumption used in elliptic curve cryptography. The XDH assumption holds that there exist certain subgroups of elliptic curves which have useful properties for cryptography. Specifically, XDH implies the existence of two distinct groups \langle_1, _2\rangle with the following properties: # The discrete logarithm problem (DLP), the computational Diffie–Hellman problem (CDH), and the computational co-Diffie–Hellman problem are all intractable in _1 and _2. # There exists an efficiently computable bilinear map (pairing) e(\cdot, \cdot) : _1 \times _2 \rightarrow _T. # The decisional Diffie–Hellman problem (DDH) is intractable in _1. The above formulation is referred to as asymmetric XDH. A stronger version of the assumption (symmetric XDH, or SXDH) holds if DDH is ''also'' intractable in _2. The XDH assumption is used in some pairing-based cryptographic protocols. In certain elli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computational Hardness Assumption
In computational complexity theory, a computational hardness assumption is the hypothesis that a particular problem cannot be solved efficiently (where ''efficiently'' typically means "in polynomial time"). It is not known how to prove (unconditional) hardness for essentially any useful problem. Instead, computer scientists rely on reductions to formally relate the hardness of a new or complicated problem to a computational hardness assumption about a problem that is better-understood. Computational hardness assumptions are of particular importance in cryptography. A major goal in cryptography is to create cryptographic primitives with provable security. In some cases, cryptographic protocols are found to have information theoretic security; the one-time pad is a common example. However, information theoretic security cannot always be achieved; in such cases, cryptographers fall back to computational security. Roughly speaking, this means that these systems are secure ''assuming th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Key Exchange
Key exchange (also key establishment) is a method in cryptography by which cryptographic keys are exchanged between two parties, allowing use of a cryptographic algorithm. If the sender and receiver wish to exchange encrypted messages, each must be equipped to encrypt messages to be sent and decrypt messages received. The nature of the equipping they require depends on the encryption technique they might use. If they use a code, both will require a copy of the same codebook. If they use a cipher, they will need appropriate keys. If the cipher is a symmetric key cipher, both will need a copy of the same key. If it is an asymmetric key cipher with the public/private key property, both will need the other's public key. Channel of exchange Key exchange is done either in-band or out-of-band. The key exchange problem The key exchange problem describes ways to exchange whatever keys or other information are needed for establishing a secure communication channel so that no one else ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computational Hardness Assumptions
In computational complexity theory, a computational hardness assumption is the hypothesis that a particular problem cannot be solved efficiently (where ''efficiently'' typically means "in polynomial time"). It is not known how to prove (unconditional) hardness for essentially any useful problem. Instead, computer scientists rely on reductions to formally relate the hardness of a new or complicated problem to a computational hardness assumption about a problem that is better-understood. Computational hardness assumptions are of particular importance in cryptography. A major goal in cryptography is to create cryptographic primitives with provable security. In some cases, cryptographic protocols are found to have information theoretic security; the one-time pad is a common example. However, information theoretic security cannot always be achieved; in such cases, cryptographers fall back to computational security. Roughly speaking, this means that these systems are secure ''assuming th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Personal Identification Number
A personal identification number (PIN), or sometimes redundantly a PIN number or PIN code, is a numeric (sometimes alpha-numeric) passcode used in the process of authenticating a user accessing a system. The PIN has been the key to facilitating the private data exchange between different data-processing centers in computer networks for financial institutions, governments, and enterprises. PINs may be used to authenticate banking systems with cardholders, governments with citizens, enterprises with employees, and computers with users, among other uses. In common usage, PINs are used in ATM or POS transactions, secure access control (e.g. computer access, door access, car access), internet transactions, or to log into a restricted website. History The PIN originated with the introduction of the automated teller machine (ATM) in 1967, as an efficient way for banks to dispense cash to their customers. The first ATM system was that of Barclays in London, in 1967; it accepted ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Distortion Map
In signal processing, distortion is the alteration of the original shape (or other characteristic) of a signal. In communications and electronics it means the alteration of the waveform of an information-bearing signal, such as an audio signal representing sound or a video signal representing images, in an electronic device or communication channel. Distortion is usually unwanted, and so engineers strive to eliminate or minimize it. In some situations, however, distortion may be desirable. For example, in noise reduction systems like the Dolby system, an audio signal is deliberately distorted in ways that emphasize aspects of the signal that are subject to electrical noise, then it is symmetrically "undistorted" after passing through a noisy communication channel, reducing the noise in the received signal. Distortion is also used as a musical effect, particularly with electric guitars. The addition of noise or other outside signals (hum, interference) is not considered d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dan Boneh
Dan Boneh (; he, דן בונה) is an Israeli-American professor in applied cryptography and computer security at Stanford University. In 2016, Boneh was elected a member of the National Academy of Engineering for contributions to the theory and practice of cryptography and computer security. Biography Born in Israel in 1969, Boneh obtained his Ph.D. in Computer Science from Princeton University in 1996 under the supervision of Richard J. Lipton. Boneh is one of the principal contributors to the development of pairing-based cryptography, along with Matt Franklin of the University of California, Davis. He joined the faculty of Stanford University in 1997, and became professor of computer science and electrical engineering. He teaches massive open online courses on the online learning platform Coursera. In 1999 he was awarded a fellowship from the David and Lucile Packard Foundation. In 2002, he co-founded a company called Voltage Security with three of his students. The comp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MNT Curve
{{disambig ...
MNT may stand for: * /mnt in Unix, directory including mount points * Medical nutrition therapy * MNT (gene), a transcription factor * Molecular nanotechnology * Mongolian tögrög, the currency of Mongolia by ISO 4217 currency code *Mononitrotoluene, or ''meta''-nitrotoluene * MyNetworkTV, a television broadcast syndication service *Montserrat, by IAAF country code *11β-Methyl-19-nortestosterone, an anabolic-androgenic steroid *Maleonitriledithiolate, an anion found in compounds such as sodium maleonitriledithiolate Sodium maleonitriledithiolate is the chemical compound described by the formula Na2S2C2(CN)2. The name refers to the cis compound, structurally related to maleonitrile ((CHCN)2). Maleonitriledithiolate is often abbreviated mnt. It is a "dithiole ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ElGamal Encryption
In cryptography, the ElGamal encryption system is an asymmetric key encryption algorithm for public-key cryptography which is based on the Diffie–Hellman key exchange. It was described by Taher Elgamal in 1985. ElGamal encryption is used in the free GNU Privacy Guard software, recent versions of PGP, and other cryptosystems. The Digital Signature Algorithm (DSA) is a variant of the ElGamal signature scheme, which should not be confused with ElGamal encryption. ElGamal encryption can be defined over any cyclic group G, like multiplicative group of integers modulo ''n''. Its security depends upon the difficulty of a certain problem in G related to computing discrete logarithms. The algorithm ElGamal encryption consists of three components: the key generator, the encryption algorithm, and the decryption algorithm. Key generation The first party, Alice, generates a key pair as follows: * Generate an efficient description of a cyclic group G\, of order q\, with g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Secret Handshakes
A secret handshake is a distinct form of handshake or greeting which indicates membership in or loyalty to a club, clique or subculture. The typical secret handshake involves placing one's fingers or thumbs in a particular position, one that will be recognized by fellow members while seeming to be a normal handshake to non-members. This is most frequently associated in the popular consciousness with college fraternities, fraternal orders and secret societies. A secret handshake can also be a useful form of familiar interaction between friends, colleagues, and family members. Secret handshakes are shared only with select and elect peoples. Usually a secret handshake has underlying meanings that differ from person to person. Secret handshakes involve a precise, sometimes complex series of movements and contact between two individuals or even a group. Usually, these movements involve the primary use of hands, but could also involve touching feet, elbows, or in some cultures a frie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Identity Based Encryption
ID-based encryption, or identity-based encryption (IBE), is an important primitive of ID-based cryptography. As such it is a type of public-key encryption in which the public key of a user is some unique information about the identity of the user (e.g. a user's email address). This means that a sender who has access to the public parameters of the system can encrypt a message using e.g. the text-value of the receiver's name or email address as a key. The receiver obtains its decryption key from a central authority, which needs to be trusted as it generates secret keys for every user. ID-based encryption was proposed by Adi Shamir in 1984. He was however only able to give an instantiation of identity-based signatures. Identity-based encryption remained an open problem for many years. The pairing-based Boneh–Franklin scheme and Cocks's encryption scheme based on quadratic residues both solved the IBE problem in 2001. Usage Identity-based systems allow any party to generate a pu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elliptic Curve Cryptography
Elliptic-curve cryptography (ECC) is an approach to public-key cryptography based on the algebraic structure of elliptic curves over finite fields. ECC allows smaller keys compared to non-EC cryptography (based on plain Galois fields) to provide equivalent security.Commercial National Security Algorithm Suite and Quantum Computing FAQ U.S. National Security Agency, January 2016. Elliptic curves are applicable for , s, [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
