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 structured set of data held in a computer, esp. one that is accessible in various ways.
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an attack model for cryptanalysis in which the cryptanalyst gathers information, at least in part, by choosing a ciphertext and obtaining its decryption under an un…
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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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a password that is valid for only one session or transaction.
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a cryptographic hash function designed by Guido Bertoni, Joan Daemen, Michaël Peeters, and Gilles Van Assche.
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Encryption using a key derived from a password or passphrase entered by the user.
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a classical cipher that shifts each plaintext character by the value of the key at the same position modulo the key-length.
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Quantum cryptography describes the use of quantum mechanical effects to perform cryptographic tasks or to break cryptographic systems.
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an algorithm for producing digital signatures. The algorithm is based on Edwards curves introduced by Bernstein et al. (2007) and named after mathematician Harold M. Edwards.
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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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an encryption algorithm that can be used as a replacement for the DES or IDEA algorithms. Blowfish was designed in 1993 by Bruce Schneier as an alternative to existing encryption algorithm…
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Performance defines the abilities of a cipher in terms of processing throughput on various platforms, including its memory requirements.
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based on a mathematical problem that is moderate hard to solve but easy to verify.
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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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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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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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Anonymity describes the state of being unknown or unacknowledged.
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a protocol where one party commits themselves to a secret value without revealing it. At a later point, the value can be revealed.
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for questions about cryptographic algorithms which were invented (and used) before the computer age.
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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 reduction in size of data without losing information.
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In a blind signature scheme, the signer does not know what he is signing. This is an important building block of anonymous voting or digital cash schemes, because it allows an authority to control the…
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a function that cannot be distinguished (with practical effort) from a permutation selected at random with uniform probability from the family of all permutations …
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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 dynamic, object-oriented, prototype-based, weakly typed language commonly used for scripting in web browsers. Despite the name, it is unrelated to the Java programming language and sha…
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Difficulty of finding another input string that hashes to the same value as a given string
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a digital peer-to-peer currency with no central authority. It was created in 2009 by Satoshi Nakamoto. Transactions are managed entirely by the network.
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a key derivation function specified in RFC5869.
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produces ciphertext that, by itself, does not reveal information about the original message besides its length
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side channel attack based on the different speed at which certain operations are executed.
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a sequence of bytes or bits, having a fixed length (the block-size).
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a type of public-key encryption in which the key used for encryption is based on selected attributes of the readers. Decryption of the ciphertext is possible only if the …
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an optimized brute-force attack that significantly reduces the number of keys the attacker needs to try by utilizing a time-space trade-off. Work is done from the begi…
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the central producer and manager of signals intelligence for the United States Government.
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an encryption algorithm which is based on the shortest vector problem in a lattice.
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A backdoor in a cryptosystem or algorithm allows someone to obtain access to the decrypted data, without the need for the key/password that was used to encrypt the data.