Digital Signature Algorithm
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Digital Signature Algorithm
The Digital Signature Algorithm (DSA) is a Public-key cryptography, public-key cryptosystem and Federal Information Processing Standards, Federal Information Processing Standard for digital signatures, based on the mathematical concept of modular exponentiation and the Discrete logarithm, discrete logarithm problem. In a digital signature system, there is a keypair involved, consisting of a private and a public key. In this system a signing entity that declared their public key can generate a signature using their private key, and a verifier can assert the source if it verifies the signature correctly using the declared public key. DSA is a variant of the Schnorr signature, Schnorr and ElGamal signature scheme, ElGamal signature schemes. The National Institute of Standards and Technology (NIST) proposed DSA for use in their Digital Signature Standard (DSS) in 1991, and adopted it as FIPS 186 in 1994. Five revisions to the initial specification have been released. The newest specifi ...
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Public-key Cryptography
Public-key cryptography, or asymmetric cryptography, is the field of cryptographic systems that use pairs of related keys. Each key pair consists of a public key and a corresponding private key. Key pairs are generated with cryptographic algorithms based on mathematical problems termed one-way functions. Security of public-key cryptography depends on keeping the private key secret; the public key can be openly distributed without compromising security. There are many kinds of public-key cryptosystems, with different security goals, including digital signature, Diffie–Hellman key exchange, Key encapsulation mechanism, public-key key encapsulation, and public-key encryption. Public key algorithms are fundamental security primitives in modern cryptosystems, including applications and protocols that offer assurance of the confidentiality and authenticity of electronic communications and data storage. They underpin numerous Internet standards, such as Transport Layer Security, T ...
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Claus P
Claus (sometimes Clas) is both a given name and a German, Danish, and Dutch surname. Notable people with the name include: Given name *Claus von Amsberg, Prince Claus of the Netherlands, Jonkheer van Amsberg (1926–2002) * Claus-Casimir of Orange-Nassau, Count of Orange-Nassau, Jonkheer van Amsberg (born 2004) * Claus von Bülow (1926–2019), British socialite accused of attempting to murder his wife, Sunny von Bülow * Claus Clausen (other), three people of that name * Claus Jacob (born 1969), German scientist * Claus Jørgensen (racewalker) (born 1974), Danish racewalker *Claus Bech Jørgensen (born 1976), Danish-born Faroese footballer * Claus Larsen (other), three people of that name * Claus Lundekvam (born 1973), Norwegian former footballer * Claus Moser, Baron Moser (1922–2015), British statistician * Claus Nielsen (born 1964), Danish former football striker *Claus Norreen (born 1970), Danish musician with the band Aqua, and record producer *Claus Offe ...
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Botan (programming Library)
Botan is a BSD licenses, BSD-licensed cryptographic and TLS library written in C++11. It provides a wide variety of cryptographic algorithms, formats, and protocols, e.g. Transport Layer Security, SSL and TLS. It is used in the Monotone (software), Monotone distributed revision control program, the OpenDNSSEC system, and Kea (software), ISC's Kea DHCP server among other projects. The project was originally called OpenCL, a name now used by Apple Inc. and Khronos Group for a OpenCL, heterogeneous system programming framework. It was renamed Botan in 2002. In 2007, the German Federal Office for Information Security contracted FlexSecure GmbH to add an implementation of Card Verifiable Certificates for epassport, ePassports to Botan; the modified version of Botan was released under the name InSiTo. Starting in 2015, the German Federal Office for Information Security funded a project, which included improving the documentation, test suite and feature set of Botan, culminating in 20 ...
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Offline Private Key
A paper key is a machine-readable print of a cryptographic key. The printed key can be used to decrypt data, e.g. archives or backup data. A paper key can be the result of an offline private key protocol. The offline private key can also function as a token in two-factor authentication. The idea is that a digital key to decrypt and recover sensitive or personal data should have long-term durability and not be stored on any computer or network. The length of secure cryptographic keys restricts memorization, so the secret key takes the form of a 2D barcode, a machine-readable print. Early implementations of a paper key by the company Safeberg use a Data Matrix barcode. or human-readable base 16 digits."Paperkey - an OpenPGP key archiver"
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Subliminal Channel
In cryptography, subliminal channels are covert channels that can be used to communicate secretly in normal looking communication over an insecure channel.Gustavus J. Simmons. The Prisoners Problem and the Subliminal Channel'. In Advances in Cryptology – CRYPTO ’83, pages 51–67, New York, 1984. Lecture Notes in Computer Science, ed. D. Chaum. Subliminal channels in digital signature crypto systems were found in 1984 by Gustavus Simmons. Simmons describes how the "Prisoners' Problem" can be solved through parameter substitution in digital signature algorithms.Gustavus J. Simmons. The subliminal channel and digital signatures'. In Proc. of the EUROCRYPT 84 workshop on Advances in Cryptology – theory and application of cryptographic techniques, pages 364–378, New York, NY, USA, 1985. Springer-Verlag New York, Inc. Signature algorithms like ElGamal and DSA have parameters which must be set with random information. He shows how one can make use of these parameters to s ...
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PlayStation 3
The PlayStation 3 (PS3) is a home video game console developed and marketed by Sony Computer Entertainment (SCE). It is the successor to the PlayStation 2, and both are part of the PlayStation brand of consoles. The PS3 was first released on November 11, 2006, in Japan, followed by November 17 in North America and March 23, 2007, in Europe and Australasia. It competed primarily with Microsoft's Xbox 360 and Nintendo's Wii as part of the seventh generation of video game consoles. The PlayStation 3 was built around the custom-designed Cell Broadband Engine processor, co-developed with IBM and Toshiba. SCE president Ken Kutaragi envisioned the console as a supercomputer for the living room, capable of handling complex multimedia tasks. It was the first console to use the Blu-ray disc as its primary storage medium, the first to be equipped with an HDMI port, and the first capable of outputting games in 1080p (Full HD) resolution. It also launched alongside the PlayStation Network ...
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Sony
is a Japanese multinational conglomerate (company), conglomerate headquartered at Sony City in Minato, Tokyo, Japan. The Sony Group encompasses various businesses, including Sony Corporation (electronics), Sony Semiconductor Solutions (imaging and sensing), Sony Entertainment (including Sony Pictures and Sony Music Group), Sony Interactive Entertainment (video games), Sony Financial Group, and others. Sony was founded in 1946 as by Masaru Ibuka and Akio Morita. In 1958, the company adopted the name Initially an electronics firm, it gained early recognition for products such as the TR-55 transistor radio and the CV-2000 home video tape recorder, contributing significantly to Japan's Japanese economic miracle, post-war economic recovery. After Ibuka's retirement in the 1970s, Morita served as chairman until 1994, overseeing Sony's rise as a global brand recognized for innovation in consumer electronics. Landmark products included the Trinitron color television, the Walkma ...
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ECDSA
In cryptography, the Elliptic Curve Digital Signature Algorithm (ECDSA) offers a variant of the Digital Signature Algorithm (DSA) which uses elliptic-curve cryptography. Key and signature sizes As with elliptic-curve cryptography in general, the bit size of the private key believed to be needed for ECDSA is about twice the size of the security level, in bits. For example, at a security level of 80 bits—meaning an attacker requires a maximum of about 2^ operations to find the private key—the size of an ECDSA private key would be 160 bits. On the other hand, the signature size is the same for both DSA and ECDSA: approximately 4 t bits, where t is the exponent in the formula 2^, that is, about 320 bits for a security level of 80 bits, which is equivalent to 2^ operations. Signature generation algorithm Suppose Alice wants to send a signed message to Bob. Initially, they must agree on the curve parameters (\textrm, G, n). In addition to the field and equation of the cu ...
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Fermat's Little Theorem
In number theory, Fermat's little theorem states that if is a prime number, then for any integer , the number is an integer multiple of . In the notation of modular arithmetic, this is expressed as a^p \equiv a \pmod p. For example, if and , then , and is an integer multiple of . If is not divisible by , that is, if is coprime to , then Fermat's little theorem is equivalent to the statement that is an integer multiple of , or in symbols: a^ \equiv 1 \pmod p. For example, if and , then , and is a multiple of . Fermat's little theorem is the basis for the Fermat primality test and is one of the fundamental results of elementary number theory. The theorem is named after Pierre de Fermat, who stated it in 1640. It is called the "little theorem" to distinguish it from Fermat's Last Theorem.. History Pierre de Fermat first stated the theorem in a letter dated October 18, 1640, to his friend and confidant Frénicle de Bessy. His formulation is equivalent to the following ...
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Extended Euclidean Algorithm
In arithmetic and computer programming, the extended Euclidean algorithm is an extension to the Euclidean algorithm, and computes, in addition to the greatest common divisor (gcd) of integers ''a'' and ''b'', also the coefficients of Bézout's identity, which are integers ''x'' and ''y'' such that : ax + by = \gcd(a, b). This is a certifying algorithm, because the gcd is the only number that can simultaneously satisfy this equation and divide the inputs. It allows one to compute also, with almost no extra cost, the quotients of ''a'' and ''b'' by their greatest common divisor. also refers to a very similar algorithm for computing the polynomial greatest common divisor and the coefficients of Bézout's identity of two univariate polynomials. The extended Euclidean algorithm is particularly useful when ''a'' and ''b'' are coprime. With that provision, ''x'' is the modular multiplicative inverse of ''a'' modulo ''b'', and ''y'' is the modular multiplicative inverse of ''b'' mod ...
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SHA-2
SHA-2 (Secure Hash Algorithm 2) is a set of cryptographic hash functions designed by the United States National Security Agency (NSA) and first published in 2001. They are built using the Merkle–Damgård construction, from a one-way compression function itself built using the Davies–Meyer structure from a specialized block cipher. SHA-2 includes significant changes from its predecessor, SHA-1. The SHA-2 family consists of six hash functions with digests (hash values) that are 224, 256, 384 or 512 bits: SHA-224, SHA-256, SHA-384, SHA-512, SHA-512/224, SHA-512/256. SHA-256 and SHA-512 are hash functions whose digests are eight 32-bit and 64-bit words, respectively. They use different shift amounts and additive constants, but their structures are otherwise virtually identical, differing only in the number of rounds. SHA-224 and SHA-384 are truncated versions of SHA-256 and SHA-512 respectively, computed with different initial values. SHA-512/224 and SHA-512/256 are also truncate ...
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SHA-1
In cryptography, SHA-1 (Secure Hash Algorithm 1) is a hash function which takes an input and produces a 160-bit (20-byte) hash value known as a message digest – typically rendered as 40 hexadecimal digits. It was designed by the United States National Security Agency, and is a U.S. Federal Information Processing Standard. The algorithm has been cryptographically broken but is still widely used. Since 2005, SHA-1 has not been considered secure against well-funded opponents; as of 2010 many organizations have recommended its replacement. NIST formally deprecated use of SHA-1 in 2011 and disallowed its use for digital signatures in 2013, and declared that it should be phased out by 2030. , chosen-prefix attacks against SHA-1 are practical. As such, it is recommended to remove SHA-1 from products as soon as possible and instead use SHA-2 or SHA-3. Replacing SHA-1 is urgent where it is used for digital signatures. All major web browser vendors ceased acceptance of SHA-1 SSL certifi ...
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