# 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:
 encryption× 1028 the process of transforming plaintext using a cipher into ciphertext to make it unreadable to anyone except those possessing the key. Decryption is the process of transforming that ciphe… hash× 726 a function which takes a variable size input and produces a fixed size output. The algorithm makes it difficult to predict the output for a given input, find two inpu… rsa× 684 an asymmetric (e.g. public-key) cryptosystem, based on modular exponentiation with big exponents and modulus. RSA can be used both for signature and encryption. aes× 557 a symmetrical block-cipher algorithm with a 128-bit block size, and key sizes of 128, 192 or 256 bits. public-key× 516 an encryption scheme using a pair of keys, one to encrypt and a second to decrypt a message. A special class of asymmetric ciphers are public-key ciphers, in which the encrypti… cryptanalysis× 461 analysing cryptographic algorithms, potentially uncovering weaknesses in them (e.g. "breaking" them or casting doubts on their actual security) elliptic-curves× 325 a mathematical structure. In cryptography, it is common to use the structure $y^2 = x^3 + ax^2 + b$ over a finite field. Questions relating to elliptic curves and derived algorithm… block-cipher× 312 an encryption algorithm which encrypts fixed-size blocks of plaintext to same-sized blocks of ciphertext. For good ciphers every bit of the ciphertext block depends on every bit of t… signature× 283 Algorithms and protocols for creating signatures to documents, and verifying such signatures. These are normally asymmetric, for symmetric signatures see [mac]. protocol-design× 248 Design of cryptographic protocols, i.e. ways of using algorithms (primitives) to achieve one or more security goals like integrity, confidentiality, authenticity (maybe together with non-security-rela… random-number-generator× 223 creation of (real or pseudo) random numbers (or bits). symmetric× 208 Symmetric cryptosystems assume two communicating entities share a pre-established secret key. algorithm-design× 204 Design of cryptographic primitives (algorithms), like block ciphers, stream ciphers, random-number generators, hash functions, MACs, key exchanges, public-key encryption or signature schemes. Also tag… keys× 200 usually secret information used as input to various kinds of cryptographic algorithms, like encryption, signature, MAC, to select the concrete transformation done by the algorithm. authentication× 196 successfully validating that an entity you are communicating with is actually who they claim to be. The entity typically demonstrates who they are by showing they possess a secret th… diffie-hellman× 194 an anonymous, non-authenticated key-agreement protocol. passwords× 166 secret keys which human beings can memorize. implementation× 161 the process of taking it from its mathematical or algorithmic description and producing a working version, often in computer software or hardware. This tag should … mac× 161 (or message authentication code), a short piece of information used to authenticate a message, and the algorithm to create and check such information, using a secret key. hmac× 161 a method for constructing a message authentication code based on a cryptographic hash function. provable-security× 155 A primitive or protocol with provable security is accompanied by a mathematical proof that shows how to reduce the security claims about the protocol to a set of assumptions. reference-request× 149 a request to be provided with (links to) documentation, official papers, and specs related to one or more specific algorithms or cryptographic procedures, to provide a trusted b… stream-cipher× 149 an encryption algorithm which encrypts arbitrary length plain text, using a (fixed length) key. Some stream ciphers generate a key stream from only the key, which is then XOR-combin… ssl× 147 SSL (Secure Sockets Layer) and its successor TLS (Transport Layer Security) are protocols which provide communication security (privacy and integrity) for a bidirectional data channel. homomorphic-encryption× 146 Cryptosystems which support computation on encrypted data. They might be partially homomorphic (support for one operation such as + or *) or they might be fully homomorphic (any sequence of + and *). key-exchange× 145 Key exchange protocols allow two parties to produce a secret session key over a public channel. cbc× 135 a method for encrypting large amounts of data with a block cipher that can only encrypt fixed length plaintexts. When used with an unpredictable initialization vector (I… collision-resistance× 130 Difficulty of finding two different inputs that hash to the same value modes-of-operation× 129 ways of applying a block cipher to multi-block messages and enabling repeated use without changing the key. key-derivation× 126 In cryptography, a key derivation function (or KDF) derives one or more secret keys from a secret value such as a master key or other known information such as a password or passphrase using a pseudo-… discrete-logarithm× 116 the number of times a generator of a group must be multiplied by itself to produce a known number. By choosing certain groups, the task of finding a discrete l… prime-numbers× 110 an integer greater than 1 with no divisors other than itself and 1. Primes and prime products play an important role in public key cryptography. initialization-vector× 109 Random data used by block cipher modes of operation to randomize the output in order to achieve semantic security. Also for other similar constructs in other iterative algorithms. des× 109 (or Data Encryption Standard), a (symmetric) block cipher using a 64 bit block size, with keys of size 56 bit, the standard US block cipher from 1976 to 2001. authenticated-encryption× 107 Combination of encryption and authentication in a way that ensures confidentiality and integrity. randomness× 104 Usage of randomness (i.e. non-predictable data, usually in the form of bits or numbers) for cryptographic purposes.