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A tag is a keyword or label that categorizes your question with other, similar questions. Using the right tags makes it easier for others to find and answer your question.

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a method of building a message authentication code from a block-cipher.
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A block cypher encryption algorithm built from applying three iterations of the original DES algorithm.
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Using the same key for more than one purpose, e.g. to encrypt two messages or to encrypt and authenticate a message. Some cryptosystems may be vulnerable to attacks if keys are inappropriately reused.
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part of the SHA-2 family of hash functions with a 512-bit output and a 256-bit security level.
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a cryptographic hash function designed by Guido Bertoni, Joan Daemen, Michaël Peeters, and Gilles Van Assche.
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In identity-based encryption (IBE) the public key of a user $A$ is some identity string $ID_A$, e.g., an email address. To encrypt a message for this user there is no need to retrieve an authentic cop…
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side channel attack based on the different speed at which certain operations are executed.
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an active attack where the attacker is able to interpose himself between the sender and receiver. The attacker may monitor and/or modify some or all of the messag…
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Multiple encryption means encrypting a message two or more times using either the same, or a different algorithm.
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Questions about official cryptographic standards and their implementation.
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an intentionally slow hash algorithm specially designed for passwords.
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the process of generating keys for cryptographic purposes.
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the act of transforming information from one form to another. In cryptography, encoding is typically used to refer to an unkeyed process that does not provide any security in itself, but j…
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Questions on the meaning, history, and usage of symbols and notation in cryptography. Please remember to mention where (book, paper, webpage, etc.) you encountered any notation you are asking about.
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a known plaintext attack and uses a linear approximation to describe the behavior of the block cipher. Given sufficient pairs of plaintext and corresponding ciphertext, bits of…
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short for Public Key Infrastructure. The foundation of a PKI is the certificate authority (CA), which issues digital certificates that authenticate the identity of organizations and individuals…
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a key derivation function specified in RFC5869.
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a family of stream ciphers proposed by Daniel J. Bernstein, as an evolution of Salsa20 with (conjecturally) improved resistance to cryptanalysis.
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Advanced Encryption Standard Galois/Counter Mode, better known as AES-GCM is a mode of operation for symmetric key cryptographic block ciphers that has been widely adopted because of its efficiency an…
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a form of cryptanalysis which studies cryptographic algorithms by observing how differences in input affect differences on output.
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a cryptanalytic technique. Birthday attacks can be used to find collisions in a cryptographic hash function. For instance, suppose we have a hash function which, when supplied wit…
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History of cryptography and cryptanalysis. Questions that wish to ask about the history of cryptography should use this tag; if you're asking about historical ciphers you may also wish to use the clas…
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the reduction in size of data without losing information.
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Data privacy refers to (cryptographic) methods to prevent the disclosure of sensitive (identifying) information of persons.
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Format-preserving encryption (FPE) refers to encrypting in such a way that the output has the same length as the input, or otherwise has the same format or structure as the input.
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The Merkle–Damgård construction — used in the design of many popular hash algorithms such as MD5, SHA1 and SHA2 — is a method of building collision-resistant cryptographic hash functions from collisio…
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A digital signature scheme based on the discrete logarithm problem, published by Taher ElGamal in 1984. Not to be confused with the ElGamal encryption system.
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an encryption algorithm which is based on the shortest vector problem in a lattice.
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Oblivious transfer refers to a cryptographic protocol in which a sender possesses a set of data and a receiver queries the sender for a particular member of that set in such a way that the sender does…
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based on a mathematical problem that is moderate hard to solve but easy to verify.
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produces ciphertext that, by itself, does not reveal information about the original message besides its length
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the art and science of writing hidden messages in such a way that no one, apart from the sender and intended recipient, suspects the existence of the message. While cryptography prot…
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a sequence of bytes or bits, having a fixed length (the block-size).
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A slow and memory-intensive hash function designed for passwords
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a family of stream ciphers built on a pseudo-random function.