ROCA Attack
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ROCA Attack
The ROCA vulnerability is a cryptographic weakness that allows the private key of a key pair to be recovered from the public key in keys generated by devices with the vulnerability. "ROCA" is an acronym for "Return of Coppersmith's attack". The vulnerability has been given the identifier . The vulnerability arises from a problem with an approach to RSA key generation used in vulnerable versions of a software library, ''RSALib'', provided by Infineon Technologies, and incorporated into many smart cards, Trusted Platform Module (TPM), and Hardware Security Modules (HSM) implementations, including YubiKey 4 tokens, often used to generate PGP keys. Keys of lengths 512, 1024, and 2048 bits generated using these versions of the Infineon library are vulnerable to a practical ROCA attack. The research team that discovered the attack (all with Masaryk University and led by Matúš Nemec and Marek Sýs) estimate that it affected around one-quarter of all current TPM devices global ...
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Masaryk University
Masaryk University (MU) ( cs, Masarykova univerzita; la, Universitas Masarykiana Brunensis) is the second largest university in the Czech Republic, a member of the Compostela Group and the Utrecht Network. Founded in 1919 in Brno as the second Czech university (after Charles University established in 1348 and Palacký University existent in 1573–1860), it now consists of ten faculties and 35,115 students. It is named after Tomáš Garrigue Masaryk, the first president of an independent Czechoslovakia as well as the leader of the movement for a second Czech university. In 1960 the university was renamed ''Jan Evangelista Purkyně University'' after Jan Evangelista Purkyně, a Czech biologist. In 1990, following the Velvet Revolution it regained its original name. Since 1922, over 171,000 students have graduated from the university. History Masaryk University was founded on 28 January 1919 with four faculties: Law, Medicine, Science, and Arts. Tomáš Garrigue Masaryk, pro ...
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Responsible Disclosure
In computer security, coordinated vulnerability disclosure, or "CVD" (formerly known as responsible disclosure) is a vulnerability disclosure model in which a vulnerability or an issue is disclosed to the public only after the responsible parties have been allowed sufficient time to patch or remedy the vulnerability or issue. This coordination distinguishes the CVD model from the " full disclosure" model. Developers of hardware and software often require time and resources to repair their mistakes. Often, it is ethical hackers who find these vulnerabilities. Hackers and computer security scientists have the opinion that it is their social responsibility to make the public aware of vulnerabilities. Hiding problems could cause a feeling of false security. To avoid this, the involved parties coordinate and negotiate a reasonable period of time for repairing the vulnerability. Depending on the potential impact of the vulnerability, the expected time needed for an emergency fix or wor ...
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Estonian Identity Card
The Estonian identity card ( et, ID-kaart) is a mandatory identity document for citizens of Estonia. In addition to regular identification of a person, an ID-card can also be used for establishing one's identity in electronic environment and for giving one's digital signature. Within Europe (except Belarus, Russia, Ukraine and United Kingdom) as well as French overseas territories and Georgia, the Estonian ID Card can be used by the citizens of Estonia as a travel document. The mandatory identity document of a citizen of the European Union is also an identity card, also known as an ID card. The Estonian ID Card can be used to cross the Estonian border, however Estonian authorities cannot guarantee that other EU member states will accept the card as a travel document. In addition to regular identification of a person, an ID-card can also be used for establishing one's identity in electronic environment and for giving one's digital signature. With the Estonian ID-card the citizen ...
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Common Criteria
The Common Criteria for Information Technology Security Evaluation (referred to as Common Criteria or CC) is an international standard (ISO/IEC 15408) for computer security certification. It is currently in version 3.1 revision 5. Common Criteria is a framework in which computer system users can ''specify'' their security ''functional'' and ''assurance'' requirements (SFRs and SARs respectively) in a Security Target (ST), and may be taken from Protection Profiles (PPs). Vendors can then ''implement '' or make claims about the security attributes of their products, and testing laboratories can ''evaluate'' the products to determine if they actually meet the claims. In other words, Common Criteria provides assurance that the process of specification, implementation and evaluation of a computer security product has been conducted in a rigorous and standard and repeatable manner at a level that is commensurate with the target environment for use. Common Criteria maintains a list of ce ...
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OpenSSL
OpenSSL is a software library for applications that provide secure communications over computer networks against eavesdropping or need to identify the party at the other end. It is widely used by Internet servers, including the majority of HTTPS websites. OpenSSL contains an open-source implementation of the SSL and TLS protocols. The core library, written in the C programming language, implements basic cryptographic functions and provides various utility functions. Wrappers allowing the use of the OpenSSL library in a variety of computer languages are available. The OpenSSL Software Foundation (OSF) represents the OpenSSL project in most legal capacities including contributor license agreements, managing donations, and so on. OpenSSL Software Services (OSS) also represents the OpenSSL project for support contracts. OpenSSL is available for most Unix-like operating systems (including Linux, macOS, and BSD), Microsoft Windows and OpenVMS. Project history The OpenSSL ...
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GitHub
GitHub, Inc. () is an Internet hosting service for software development and version control using Git. It provides the distributed version control of Git plus access control, bug tracking, software feature requests, task management, continuous integration, and wikis for every project. Headquartered in California, it has been a subsidiary of Microsoft since 2018. It is commonly used to host open source software development projects. As of June 2022, GitHub reported having over 83 million developers and more than 200 million repositories, including at least 28 million public repositories. It is the largest source code host . History GitHub.com Development of the GitHub.com platform began on October 19, 2007. The site was launched in April 2008 by Tom Preston-Werner, Chris Wanstrath, P. J. Hyett and Scott Chacon after it had been made available for a few months prior as a beta release. GitHub has an annual keynote called GitHub Universe. Organizational ...
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Smooth Number
In number theory, an ''n''-smooth (or ''n''-friable) number is an integer whose prime factors are all less than or equal to ''n''. For example, a 7-smooth number is a number whose every prime factor is at most 7, so 49 = 72 and 15750 = 2 × 32 × 53 × 7 are both 7-smooth, while 11 and 702 = 2 × 33 × 13 are not 7-smooth. The term seems to have been coined by Leonard Adleman. Smooth numbers are especially important in cryptography, which relies on factorization of integers. The 2-smooth numbers are just the powers of 2, while 5-smooth numbers are known as regular numbers. Definition A positive integer is called B-smooth if none of its prime factors are greater than B. For example, 1,620 has prime factorization 22 × 34 × 5; therefore 1,620 is 5-smooth because none of its prime factors are greater than 5. This definition includes numbers that lack some of the smaller prime factors; for example, both 10 and 12 are 5-smooth, even though they miss out the prime factors 3 and 5, resp ...
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Pohlig–Hellman Algorithm
In group theory, the Pohlig–Hellman algorithm, sometimes credited as the Silver–Pohlig–Hellman algorithm, Mollin 2006, pg. 344 is a special-purpose algorithm for computing discrete logarithms in a finite abelian group whose order is a smooth integer. The algorithm was introduced by Roland Silver, but first published by Stephen Pohlig and Martin Hellman (independent of Silver). Groups of prime-power order As an important special case, which is used as a subroutine in the general algorithm (see below), the Pohlig–Hellman algorithm applies to groups whose order is a prime power. The basic idea of this algorithm is to iteratively compute the p-adic digits of the logarithm by repeatedly "shifting out" all but one unknown digit in the exponent, and computing that digit by elementary methods. (Note that for readability, the algorithm is stated for cyclic groups — in general, G must be replaced by the subgroup \langle g\rangle generated by g, which is always cyclic.) :Input. ...
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65537
65537 is the integer after 65536 and before 65538. In mathematics 65537 is the largest known prime number of the form 2^ +1 (n = 4). Therefore, a regular polygon with 65537 sides is constructible with compass and unmarked straightedge. Johann Gustav Hermes gave the first explicit construction of this polygon. In number theory, primes of this form are known as Fermat primes, named after the mathematician Pierre de Fermat. The only known prime Fermat numbers are 2^ + 1 = 2^ + 1 = 3, 2^ + 1= 2^ +1 = 5, 2^ + 1 = 2^ +1 = 17, 2^ + 1= 2^ + 1= 257, 2^ + 1 = 2^ + 1 = 65537. In 1732, Leonhard Euler found that the next Fermat number is composite: 2^ + 1 = 2^ + 1 = 4294967297 = 641 \times 6700417 In 1880, showed that 2^ + 1 = 2^ + 1 = 274177 \times 67280421310721 65537 is also the 17th Jacobsthal–Lucas number, and currently the largest known integer ''n'' for which the number 10^ + 27 is a probable prime. Applications 65537 is commonly used as a public exponent in the RSA cr ...
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Discrete Logarithm
In mathematics, for given real numbers ''a'' and ''b'', the logarithm log''b'' ''a'' is a number ''x'' such that . Analogously, in any group ''G'', powers ''b''''k'' can be defined for all integers ''k'', and the discrete logarithm log''b'' ''a'' is an integer ''k'' such that . In number theory, the more commonly used term is index: we can write ''x'' = ind''r'' ''a'' (mod ''m'') (read "the index of ''a'' to the base ''r'' modulo ''m''") for ''r''''x'' ≡ ''a'' (mod ''m'') if ''r'' is a primitive root of ''m'' and gcd(''a'',''m'') = 1. Discrete logarithms are quickly computable in a few special cases. However, no efficient method is known for computing them in general. Several important algorithms in public-key cryptography, such as ElGamal base their security on the assumption that the discrete logarithm problem over carefully chosen groups has no efficient solution. Definition Let ''G'' be any group. Denote its group operation by mu ...
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Coppersmith Method
The Coppersmith method, proposed by Don Coppersmith, is a method to find small integer zeroes of univariate or bivariate polynomials modulo a given integer. The method uses the Lenstra–Lenstra–Lovász lattice basis reduction algorithm (LLL) to find a polynomial that has the same zeroes as the target polynomial but smaller coefficients. In cryptography, the Coppersmith method is mainly used in attacks on RSA when parts of the secret key are known and forms a base for Coppersmith's attack. Approach Coppersmith's approach is a reduction of solving modular polynomial equations to solving polynomials over the integers. Let F(x) = x^n+a_x^+\ldots +a_1x+a_0 and assume that F(x_0)\equiv 0 \pmod for some integer , x_0, < M^. Coppersmith’s algorithm can be used to find this integer solution x_0. Finding roots over is easy using, e.g.,

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Prime Number
A prime number (or a prime) is a natural number greater than 1 that is not a product of two smaller natural numbers. A natural number greater than 1 that is not prime is called a composite number. For example, 5 is prime because the only ways of writing it as a product, or , involve 5 itself. However, 4 is composite because it is a product (2 × 2) in which both numbers are smaller than 4. Primes are central in number theory because of the fundamental theorem of arithmetic: every natural number greater than 1 is either a prime itself or can be factorized as a product of primes that is unique up to their order. The property of being prime is called primality. A simple but slow method of checking the primality of a given number n, called trial division, tests whether n is a multiple of any integer between 2 and \sqrt. Faster algorithms include the Miller–Rabin primality test, which is fast but has a small chance of error, and the AKS primality test, which always pr ...
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