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Encryption is 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…
4908 questions
A cryptographic hash algorithm is a function which takes a variable size input and produces a fixed size output. The algorithm makes it difficult to find two inputs with the same output or reconstruct…
3130 questions
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 with proper paddings.
2863 questions
AES (Advanced Encryption Standard) is a symmetrical block-cipher algorithm with a 128-bit block size, and key sizes of 128, 192 or 256 bits.
2711 questions
An asymmetric cipher is an encryption scheme using a pair of keys, one to encrypt and a second to decrypt a message. This way the encrypting key need not be kept secret to ensure a private communicati…
2412 questions
Elliptic curves are algebraic-geometric structures with applications in cryptography. Such a curve consists of the set of solutions to a cubic equation over a finite field equipped with a group operat…
2374 questions
Analysis of individual security aspects of a cipher or algorithm, not the security of a cipher or algorithm in general (which would lean towards “algorithm-design”).
1669 questions
Algorithms and protocols for creating signatures to documents, and verifying such signatures. These are normally asymmetric, for symmetric signatures see [mac].
1542 questions
A block cipher is 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…
1181 questions
Zero-knowledge proofs are an interactive method for one party to prove to another that a statement is true, without revealing anything other than the veracity of the statement.
1153 questions
The Diffie–Hellman key agreement is an anonymous, non-authenticated key-agreement protocol.
1129 questions
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 *).
953 questions
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…
950 questions
Symmetric cryptosystems assume two communicating entities share a pre-established secret key.
915 questions
Private and secret keys consists of secret information used as input to various kinds of cryptographic algorithms such as encryption, signature and MAC to select the concrete transformation done by th…
906 questions
A random number generator is a software or hardware solution which functions as a generator of (real or pseudo) random numbers (or bits).
869 questions
refers to public-key algorithms based on problems that quantum computers can't solve efficiently. Existing algorithms such as RSA, Diffie-Hellman, and ECDSA are known to be breakable using Sh…
866 questions
Difficulty of finding two different inputs that hash to the same value
770 questions
Authentication is 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…
749 questions
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.
735 questions
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…
731 questions
In cryptography, a discrete logarithm is 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…
720 questions
Lattice-cryptography is the study and use of lattice problems applied to cryptography.
713 questions
Key exchange protocols allow two parties to produce a secret session key over a public channel.
699 questions
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.
676 questions
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-…
671 questions
HMAC is a method for constructing a message authentication code based on a cryptographic hash function.
652 questions
SHA-256 is part of the SHA-2 family of hash functions with a 256-bit output and a 128-bit security level.
638 questions
(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.
609 questions
In cryptography, a pseudo-random generator (PRG) is a deterministic procedure that maps a random seed to a longer pseudo-random string such that no statistical test can distinguish between the output …
608 questions
Secret sharing refers to splitting a secret among multiple parties so that together they can reconstruct it. All parties, or just a threshold number of them, can be required for reconstruction. If few…
597 questions
Usage of randomness (i.e. non-predictable data, usually in the form of bits or numbers) for cryptographic purposes.
590 questions
Implementing a cipher or protocol is 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 …
589 questions
Combination of encryption and authentication in a way that ensures confidentiality, integrity and authentication
581 questions
A stream cipher is an encryption algorithm which encrypts arbitrary length plaintext, using a key. Some stream ciphers generate a keystream from only the key, which is then XOR-combined with the plain…
575 questions
The Digital Signature Algorithm (DSA) is a United States Federal Government standard or FIPS for digital signatures. It was proposed by the National Institute of Standards and Technology (NIST) in Aug…
567 questions