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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based on a mathematical problem that is moderate hard to solve but easy to verify.
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attacks using information leaked by implementations of cryptographic algorithms to obtain information about keys or (plaintext) data, instead of (or additional to) using cryptographic weaknesses.
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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 cryptographic hash function designed by Guido Bertoni, Joan Daemen, Michaël Peeters, and Gilles Van Assche.
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Anonymity describes the state of being unknown or unacknowledged.
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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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a method of building a message authentication code from a block-cipher.
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The National Institute of Standards and Technology (NIST) is a U.S. federal agency that works with industry to develop and apply technology, measurements, and standards.
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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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Performance defines the abilities of a cipher in terms of processing throughput on various platforms, including its memory requirements.
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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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the reduction in size of data without losing information.
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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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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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a key derivation function specified in RFC5869.
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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.
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A public-key cryptosystem invented by Pascal Paillier in 1999.
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an arbitrary number or string used only once within the context of a specific cryptographic scheme. Nonces are used e.g. in authentication protocols to prevent replay attacks, as well as …
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used to estimate the likelihood of a hypothesis given a set of data. In cryptanalysis, statistical testing is commonly used to detect non-randomness in the data, e.g. distinguis…
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The term "pen and paper" can practically be interpreted as "using no tools like electronic devices", since it targets cryptographic functions, schemes, and procedures which can be handled by humans wh…
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produces ciphertext that, by itself, does not reveal information about the original message besides its length
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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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Difficulty of finding another input string that hashes to the same value as a given string
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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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the central producer and manager of signals intelligence for the United States Government.
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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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Secure Remote Password protocol version 6.
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side channel attack based on the different speed at which certain operations are executed.
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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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an asymmetric encryption algorithm and is a candidate for "post-quantum cryptography", as it is immune to attacks using Shor's algorithm and — more generally — measuring coset…
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said to be malleable if it is feasible to modify ciphertext to produce meaningful changes in the corresponding plaintext without knowing the encryption key.
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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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A cryptographic attack tries to theoretically and/or practically attack the security properties of a cipher and/or algorithm.
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a historic polygraphic substitution cipher invented by Lester S. Hill in 1929.
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a method of hierarchically hashing data. They allow efficient parallel hashing and updates and the possibility of verifying partial data.
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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…