# Tags

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.

 Type to find tags:
 one-way-function× 85 easy to compute but hard to invert (i.e. find preimages for). The existence of one-way functions implies the possibility of many useful cryptographic schemes. No one-way functions … chosen-ciphertext-attack× 83 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… complexity× 83 Complexity describes - in simple words - how hard (complex) it is to reach a specific goal; and under which conditions. In cryptography, this mostly ends up in using the complexity theory to analyze t… group-theory× 81 an abstract algebraic concept based on a set and a group law (a binary function which closes the set). security-definition× 77 Questions about formal definitions of "security" for various cryptographic schemes (e.g. perfect secrecy, semantic security, ciphertext indistinguishability, etc.) substitution-cipher× 74 an encryption algorithm which works by replacing plaintext units with corresponding ciphertext units, following some rule depending on the key. s-boxes× 72 (or substitution boxes), components in many block ciphers used to substitute parts of the data in a non-linear way. While often fixed by the algorithm (like in DES and AES), sometimes they are key-dep… rc4× 69 a fast and simple stream cipher used correctly in SSL and incorrectly in WEP. csprng× 68 A cryptographically secure pseudorandom number generator is a pseudo-random number generator with properties that make it suitable for use in cryptography. shamir-secret-sharing× 67 a threshold secret sharing scheme based on polynomial interpolation over a finite field. ecb× 64 a mode of operation for a block cipher, with the characteristic that each possible block of plaintext has a defined corresponding ciphertext value and vice versa. nonce× 61 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 … lattice-crypto× 61 sha-2× 61 a family of cryptographic hash functions designed by the NSA and published by NIST in 2001. The family includes various output lengths (224, 256, 384, and 512 bits). hash-signature× 60 Hash-based digital signatures, such as Lamport one-time signatures, are digital signature schemes based on a (non-trapdoor) one-way function such as a cryptographic hash. Such schemes are expected to … 3des× 59 A block cypher encryption algorithm built from applying three iterations of the original DES algorithm. java× 59 an object-oriented programming language. Java programs are compiled to bytecode and run in a virtual machine (JVM). Java should not be confused with JavaScript; JavaScript is an entirely diff… identity-based-encryption× 59 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… performance× 59 Performance defines the abilities of a cipher in terms of processing throughput on various platforms, including its memory requirements. key-reuse× 58 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. cryptographic-hardware× 57 Cryptographic hardware enables the handling of cryptographic tasks and/or problems using hardware instead of software solutions. side-channel-attack× 57 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. format-preserving× 55 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. permutation× 55 A way, esp. one of several possible variations, in which a set or number of things can be ordered or arranged. preimage-resistance× 55 Difficulty of finding an input string that hashes to a given value password-based-encryption× 54 Encryption using a key derived from a password or passphrase entered by the user. integrity× 54 In a cryptographic sense, integrity means unimpaired and complete. random-oracle-model× 53 A model used in cryptographic security proofs, in which concrete primitives such as hash functions are replaced with a "random oracle": a hypothetical black box that maps its inputs to truly random ou… vigenere× 52 a classical cipher that shifts each plaintext character by the value of the key at the same position modulo the key-length. feistel-network× 52 a structure that has been used to create a number of different block ciphers (e.g., DES, Blowfish, Twofish, RC6). pki× 50 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… paillier× 48 A public-key cryptosystem invented by Pascal Paillier in 1999. nist× 48 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. bcrypt× 48 an intentionally slow hash algorithm specially designed for passwords. standards× 48 Questions about official cryptographic standards and their implementation. timing-attack× 47 side channel attack based on the different speed at which certain operations are executed.