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Kuznyechik
Kuznyechik (russian: Кузнечик, literally "grasshopper") is a symmetric block cipher. It has a block size of 128 bits and key length of 256 bits. It is defined in the National Standard of the Russian Federation GOST R 34.12-2015 and also in RFC 7801. The name of the cipher can be translated from Russian as grasshopper, however, the standard explicitly says that the English name for the cipher is ''Kuznyechik'' (). The designers claim that by naming the cipher Kuznyechik they follow the trend of difficult to pronounce algorithm names set up by Rijndael and Keccak. There is also a rumor that the cipher was named after its creators: A. S. Kuzmin, A. A. Nechaev and Company (Russian: Кузьмин, Нечаев и Компания). The standard GOST R 34.12-2015 defines the new cipher in addition to the old GOST block cipher (now called Magma) as one and does not declare the old cipher obsolete. Kuznyechik is based on a substitution–permutation network, though the key sc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GOST Block Cipher
The GOST block cipher (Magma), defined in the standard GOST 28147-89 (RFC 5830), is a Soviet and Russian government standard symmetric key block cipher with a block size of 64 bits. The original standard, published in 1989, did not give the cipher any name, but the most recent revision of the standard, GOST R 34.12-2015 (RFC 7801, RFC 8891), specifies that it may be referred to as Magma. The GOST hash function is based on this cipher. The new standard also specifies a new 128-bit block cipher called Kuznyechik. Developed in the 1970s, the standard had been marked "Top Secret" and then downgraded to "Secret" in 1990. Shortly after the dissolution of the USSR, it was declassified and it was released to the public in 1994. GOST 28147 was a Soviet alternative to the United States standard algorithm, DES. Thus, the two are very similar in structure. The algorithm GOST has a 64-bit block size and a key length of 256 bits. Its S-boxes can be secret, and they contain about 354 (lo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Substitution–permutation Network
In cryptography, an SP-network, or substitution–permutation network (SPN), is a series of linked mathematical operations used in block cipher algorithms such as AES (Rijndael), 3-Way, Kalyna, Kuznyechik, PRESENT, SAFER, SHARK, and Square. Such a network takes a block of the plaintext and the key as inputs, and applies several alternating ''rounds'' or ''layers'' of substitution boxes (S-boxes) and permutation boxes (P-boxes) to produce the ciphertext block. The S-boxes and P-boxes transform of input bits into output bits. It is common for these transformations to be operations that are efficient to perform in hardware, such as exclusive or (XOR) and bitwise rotation. The key is introduced in each round, usually in the form of "round keys" derived from it. (In some designs, the S-boxes themselves depend on the key.) Decryption is done by simply reversing the process (using the inverses of the S-boxes and P-boxes and applying the round keys in reversed order). ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nothing-up-my-sleeve Number
In cryptography, nothing-up-my-sleeve numbers are any numbers which, by their construction, are above suspicion of hidden properties. They are used in creating cryptographic functions such as hashes and ciphers. These algorithms often need randomized constants for mixing or initialization purposes. The cryptographer may wish to pick these values in a way that demonstrates the constants were not selected for a nefarious purpose, for example, to create a backdoor to the algorithm. These fears can be allayed by using numbers created in a way that leaves little room for adjustment. An example would be the use of initial digits from the number as the constants. Using digits of millions of places after the decimal point would not be considered trustworthy because the algorithm designer might have selected that starting point because it created a secret weakness the designer could later exploit. Digits in the positional representations of real numbers such as , ''e'', and irratio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Streebog
Streebog (russian: Стрибог) is a cryptographic hash function defined in the Russian national standard GOST R 34.11-2012 ''Information Technology – Cryptographic Information Security – Hash Function''. It was created to replace an obsolete GOST hash function defined in the old standard GOST R 34.11-94, and as an asymmetric reply to SHA-3 competition by the US National Institute of Standards and Technology. The function is also described in RFC 6986 and one out of hash functions in ISO/IEC 10118-3:2018. Description Streebog operates on 512-bit blocks of the input, using the Merkle–Damgård construction to handle inputs of arbitrary size. The high-level structure of the new hash function resembles the one from GOST R 34.11-94, however, the compression function was changed significantly. The compression function operates in Miyaguchi–Preneel mode and employs a 12-round AES-like cipher with a 512-bit block and 512-bit key. (It uses an 8×8 matrix of bytes rather tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Substitution–permutation Network
In cryptography, an SP-network, or substitution–permutation network (SPN), is a series of linked mathematical operations used in block cipher algorithms such as AES (Rijndael), 3-Way, Kalyna, Kuznyechik, PRESENT, SAFER, SHARK, and Square. Such a network takes a block of the plaintext and the key as inputs, and applies several alternating ''rounds'' or ''layers'' of substitution boxes (S-boxes) and permutation boxes (P-boxes) to produce the ciphertext block. The S-boxes and P-boxes transform of input bits into output bits. It is common for these transformations to be operations that are efficient to perform in hardware, such as exclusive or (XOR) and bitwise rotation. The key is introduced in each round, usually in the form of "round keys" derived from it. (In some designs, the S-boxes themselves depend on the key.) Decryption is done by simply reversing the process (using the inverses of the S-boxes and P-boxes and applying the round keys in reversed order). ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GOST
GOST (russian: ГОСТ) refers to a set of international technical standards maintained by the ''Euro-Asian Council for Standardization, Metrology and Certification (EASC)'', a regional standards organization operating under the auspices of the Commonwealth of Independent States (CIS). All sorts of regulated standards are included, with examples ranging from charting rules for design documentation to recipes and nutritional facts of Soviet-era brand names. The latter have become generic, but may only be sold under the label if the technical standard is followed, or renamed if they are reformulated. The notion of GOST has certain significance and recognition in the countries of the standards' jurisdiction. The Russian government Federal Agency on Technical Regulating and Metrology (Rosstandart) has ''gost.ru'' as its website address. History GOST standards were originally developed by the government of the Soviet Union as part of its national standardization strategy. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Time Complexity
In computer science, the time complexity is the computational complexity that describes the amount of computer time it takes to run an algorithm. Time complexity is commonly estimated by counting the number of elementary operations performed by the algorithm, supposing that each elementary operation takes a fixed amount of time to perform. Thus, the amount of time taken and the number of elementary operations performed by the algorithm are taken to be related by a constant factor. Since an algorithm's running time may vary among different inputs of the same size, one commonly considers the worst-case time complexity, which is the maximum amount of time required for inputs of a given size. Less common, and usually specified explicitly, is the average-case complexity, which is the average of the time taken on inputs of a given size (this makes sense because there are only a finite number of possible inputs of a given size). In both cases, the time complexity is generally expresse ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reverse Engineer
Reverse engineering (also known as backwards engineering or back engineering) is a process or method through which one attempts to understand through deductive reasoning how a previously made device, process, system, or piece of software accomplishes a task with very little (if any) insight into exactly how it does so. It is essentially the process of opening up or dissecting a system to see how it works, in order to duplicate or enhance it. Depending on the system under consideration and the technologies employed, the knowledge gained during reverse engineering can help with repurposing obsolete objects, doing security analysis, or learning how something works. Although the process is specific to the object on which it is being performed, all reverse engineering processes consist of three basic steps: Information extraction, Modeling, and Review. Information extraction refers to the practice of gathering all relevant information for performing the operation. Modeling refers to th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pseudo-random
A pseudorandom sequence of numbers is one that appears to be statistically random, despite having been produced by a completely deterministic and repeatable process. Background The generation of random numbers has many uses, such as for random sampling, Monte Carlo methods, board games, or gambling. In physics, however, most processes, such as gravitational acceleration, are deterministic, meaning that they always produce the same outcome from the same starting point. Some notable exceptions are radioactive decay and quantum measurement, which are both modeled as being truly random processes in the underlying physics. Since these processes are not practical sources of random numbers, people use pseudorandom numbers, which ideally have the unpredictability of a truly random sequence, despite being generated by a deterministic process. In many applications, the deterministic process is a computer algorithm called a pseudorandom number generator, which must first be provid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
S-box
In cryptography, an S-box (substitution-box) is a basic component of symmetric key algorithms which performs substitution. In block ciphers, they are typically used to obscure the relationship between the key and the ciphertext, thus ensuring Shannon's property of confusion. Mathematically, an S-box is a vectorial Boolean function. In general, an S-box takes some number of input bits, ''m'', and transforms them into some number of output bits, ''n'', where ''n'' is not necessarily equal to ''m''. An ''m''×''n'' S-box can be implemented as a lookup table with 2''m'' words of ''n'' bits each. Fixed tables are normally used, as in the Data Encryption Standard (DES), but in some ciphers the tables are generated dynamically from the key (e.g. the Blowfish and the Twofish encryption algorithms). Example One good example of a fixed table is the S-box from DES (S5), mapping 6-bit input into a 4-bit output: Given a 6-bit input, the 4-bit output is found by selecting the row using ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
