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 picture info Private Key Public-key cryptography, or asymmetric cryptography, is a cryptographic system that uses pairs of keys: public keys, which may be dPublic-key cryptography, or asymmetric cryptography, is a cryptographic system that uses pairs of keys: public keys, which may be disseminated widely, and private keys, which are known only to the owner. The generation of such keys depends on cryptographic algorithms based on mathematical problems to produce one-way functions. Effective security only requires keeping the private key private; the public key can be openly distributed without compromising security.[1] In such a system, any person can encrypt a message using the receiver's public key, but that encrypted message can only be decrypted with the receiver's private key [...More Info...]       [...Related Items...] picture info Random In the common parlance, randomness is the apparent lack of pattern or predictability in events.[1][2] A random sequence of events, symbols or steps often has no order and does not follow an intelligible pattern or combination. Individual random events are by definition unpredictable, but since they often follow a probability distribution, the frequency of different outcomes over numerous events (or "trials") is predictable.[3] For example, when throwing two dice, the outcome of any particular roll is unpredictable, but a sum of 7 will occur twice as often as 4. In this view, randomness is a measure of uncertainty of an outcome, rather than its haphazardness, and applies to concepts of chance, probability, and information entropy. According to Ramsey theory, ideal randomness is impossible especially for large structures [...More Info...]       [...Related Items...] 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.[1] 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 ${\displaystyle G}$, like multiplicative group of integers modulo n [...More Info...]       [...Related Items...] DKIM The need for email validated identification arises because forged addresses and content are otherwise easily created—and widely used in spam, phishing and other email-based fraud. For example, a fraudster may send a message claiming to be from sender@example.com, with the goal of convincing the recipient to accept and to read the email—and it is difficult for recipients to establish whether to trust this message. System administrators also have to deal with complaints about malicious email that appears to have originated from their systems, but did not.domain was indeed authorized by the owner of that domain.[1] It achieves this by affixing a digital signature, linked to a domain name, to each outgoing email message. The recipient system can verify this by looking up the sender's public key published in the DNS [...More Info...]       [...Related Items...] picture info Authentication Authentication (from Greek: αὐθεντικός authentikos, "real, genuine", from αὐθέντης authentes, "author") is the act of proving an assertion, such as the identity of a computer system user. In contrast with identification, the act of indicating a person or thing's identity, authentication is the process of verifying that identity. It might involve validating personal identity documents, verifying the authenticity of a website with a digital certificate,[1] determining the age of an artifact by carbon dating, or ensuring that a product or document is not counterfeit. Authentication is relevant to multiple fields. In art, antiques and anthropology, a common problem is verifying that a given artifact was produced by a certain person or in a certain place or period of history [...More Info...]       [...Related Items...] Key-exchange Algorithm 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 [...More Info...]       [...Related Items...] Merkle–Hellman Knapsack Cryptosystem The Merkle–Hellman knapsack cryptosystem was one of the earliest public key cryptosystems. It was published by Ralph Merkle and Martin Hellman in 1978. A polynomial time attack was published by Adi Shamir in 1984. As a result, the cryptosystem is now considered insecure.[1]:465 [2]:190 The concept of public key cryptography was introduced by Whitfield Diffie and Martin Hellman in 1976[3]. At that time they proposed only the general concept of a "trapdoor function", a function that is computationally infeasible to calculate without some secret "trapdoor" information, but they had not yet found a practical example of such a function [...More Info...]       [...Related Items...] Side-channel Attack In computer security, a side-channel attack is any attack based on information gained from the implementation of a computer system, rather than weaknesses in the implemented algorithm itself (e.g. cryptanalysis and software bugs). Timing information, power consumption, electromagnetic leaks or even sound can provide an extra source of information, which can be exploited. Some side-channel attacks require technical knowledge of the internal operation of the system, although others such as differential power analysis are effective as black-box attacks. The rise of Web 2.0 applications and software-as-a-service has also significantly raised the possibility of side-channel attacks on the web, even when transmissions between a web browser and server are encrypted (e.g [...More Info...]       [...Related Items...] picture info Man-in-the-middle Attack In cryptography and computer security, a man-in-the-middle, monster-in-the-middle,[1][2] machine-in-the-middle, monkey-in-the-middle[3] (MITM) or person-in-the-middle[4] (PITM) attack is a cyberattack where the attacker secretly relays and possibly alters the communications between two parties who believe that they are directly communicating with each other. One example of a MITM attack is active eavesdropping, in which the attacker makes independent connections with the victims and relays messages between them to make them believe they are talking directly to each other over a private connection, when in fact the entire conversation is controlled by the attacker. The attacker must be able to intercept all relevant messages passing between the two victims and inject new ones [...More Info...]       [...Related Items...]