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SAFER
In cryptography, SAFER (Secure And Fast Encryption Routine) is the name of a family of block ciphers designed primarily by James Massey (one of the designers of IDEA) on behalf of Cylink Corporation. The early SAFER K and SAFER SK designs share the same encryption function, but differ in the number of rounds and the key schedule. More recent versions — SAFER+ and SAFER++ — were submitted as candidates to the AES process and the NESSIE project respectively. All of the algorithms in the SAFER family are unpatented and available for unrestricted use. SAFER K and SAFER SK The first SAFER cipher was SAFER K-64, published by Massey in 1993, with a 64-bit block size. The "K-64" denotes a key size of 64 bits. There was some demand for a version with a larger 128-bit key, and the following year Massey published such a variant incorporating new key schedule designed by the Singapore Ministry for Home affairs: SAFER K-128. However, both Lars Knudsen and Sean Murphy found minor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SAFER
In cryptography, SAFER (Secure And Fast Encryption Routine) is the name of a family of block ciphers designed primarily by James Massey (one of the designers of IDEA) on behalf of Cylink Corporation. The early SAFER K and SAFER SK designs share the same encryption function, but differ in the number of rounds and the key schedule. More recent versions — SAFER+ and SAFER++ — were submitted as candidates to the AES process and the NESSIE project respectively. All of the algorithms in the SAFER family are unpatented and available for unrestricted use. SAFER K and SAFER SK The first SAFER cipher was SAFER K-64, published by Massey in 1993, with a 64-bit block size. The "K-64" denotes a key size of 64 bits. There was some demand for a version with a larger 128-bit key, and the following year Massey published such a variant incorporating new key schedule designed by the Singapore Ministry for Home affairs: SAFER K-128. However, both Lars Knudsen and Sean Murphy found minor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pseudo-Hadamard Transform
The pseudo-Hadamard transform is a reversible transformation of a bit string that provides cryptographic diffusion. See Hadamard transform. The bit string must be of even length so that it can be split into two bit strings ''a'' and ''b'' of equal lengths, each of ''n'' bits. To compute the transform, ''a''' and ''b''', from these we use the equations: :a' = a + b \, \pmod :b' = a + 2b\, \pmod To reverse this, clearly: :b = b' - a' \, \pmod :a = 2a' - b' \, \pmod Generalization The above equations can be expressed in matrix algebra, by considering ''a'' and ''b'' as two elements of a vector, and the transform itself as multiplication by a matrix of the form: :H_1 = \begin 2 & 1 \\ 1 & 1 \end The inverse can then be derived by inverting the matrix. However, the matrix can be generalised to higher dimensions, allowing vectors of any power-of-two size to be transformed, using the following recursive rule: :H_n = \begin 2 \times H_ & H_ \\ H_ & H_ \end For example: :H_2 = ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Twofish
In cryptography, Twofish is a symmetric key block cipher with a block size of 128 bits and key sizes up to 256 bits. It was one of the five finalists of the Advanced Encryption Standard contest, but it was not selected for standardization. Twofish is related to the earlier block cipher Blowfish. Twofish's distinctive features are the use of pre-computed key-dependent S-boxes, and a relatively complex key schedule. One half of an n-bit key is used as the actual encryption key and the other half of the n-bit key is used to modify the encryption algorithm (key-dependent S-boxes). Twofish borrows some elements from other designs; for example, the pseudo-Hadamard transform (PHT) from the SAFER family of ciphers. Twofish has a Feistel structure like DES. Twofish also employs a Maximum Distance Separable matrix. When it was introduced in 1998, Twofish was slightly slower than Rijndael (the chosen algorithm for Advanced Encryption Standard) for 128-bit keys, but somewhat faster for 2 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AES Process
The Advanced Encryption Standard (AES), the symmetric block cipher ratified as a standard by National Institute of Standards and Technology of the United States (NIST), was chosen using a process lasting from 1997 to 2000 that was markedly more open and transparent than its predecessor, the Data Encryption Standard (DES). This process won praise from the open cryptographic community, and helped to increase confidence in the security of the winning algorithm from those who were suspicious of backdoors in the predecessor, DES. A new standard was needed primarily because DES has a relatively small 56-bit key which was becoming vulnerable to brute-force attacks. In addition, the DES was designed primarily for hardware and is relatively slow when implemented in software. While Triple-DES avoids the problem of a small key size, it is very slow even in hardware, it is unsuitable for limited-resource platforms, and it may be affected by potential security issues connected with the (toda ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bluetooth
Bluetooth is a short-range wireless technology standard that is used for exchanging data between fixed and mobile devices over short distances and building personal area networks (PANs). In the most widely used mode, transmission power is limited to 2.5 milliwatts, giving it a very short range of up to . It employs UHF radio waves in the ISM bands, from 2.402GHz to 2.48GHz. It is mainly used as an alternative to wire connections, to exchange files between nearby portable devices and connect cell phones and music players with wireless headphones. Bluetooth is managed by the Bluetooth Special Interest Group (SIG), which has more than 35,000 member companies in the areas of telecommunication, computing, networking, and consumer electronics. The IEEE standardized Bluetooth as IEEE 802.15.1, but no longer maintains the standard. The Bluetooth SIG oversees development of the specification, manages the qualification program, and protects the trademarks. A manufacturer must meet ... [...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). Components ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
James Massey
James Lee Massey (February 11, 1934 – June 16, 2013) was an American information theorist and cryptographer, Professor Emeritus of Digital Technology at ETH Zurich. His notable work includes the application of the Berlekamp–Massey algorithm to linear codes, the design of the block ciphers IDEA (with Xuejia Lai, based on the Lai-Massey scheme) and SAFER, and the Massey-Omura cryptosystem (with Jim K. Omura). Biography Massey was born in Wauseon, Ohio. As a child, after the death of his father in Ohio, he moved with his mother and brother to Mendota, Illinois. At age 14, his family moved to Ottawa, Illinois. After graduating from St. Bede Academy, he entered the University of Notre Dame. He received a B.S. in electrical engineering from Notre Dame in 1956 and was granted an NSF Fellowship. After three years of military service, he began graduate studies in 1959 at MIT, where he concentrated on coding theory and was awarded a Ph.D. in 1962, with John Wozencraft as his advisor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lars Knudsen
Lars Ramkilde Knudsen (born 21 February 1962) is a Danish researcher in cryptography, particularly interested in the design and analysis of block ciphers, hash functions and message authentication codes (MACs). Academic After some early work in banking, Knudsen enrolled at Aarhus University in 1984 studying mathematics and computer science, gaining an MSc in 1992 and a PhD in 1994. From 1997-2001, he worked at the University of Bergen, Norway. Currently, Knudsen is a professor in the Department of Mathematics at the Technical University of Denmark. Ivan Damgård was Lars' mentor during his studies at Aarhus University. His Ph.D. was refereed by Bart Preneel. Publications Knudsen has published a couple of papers on cryptanalysis of cryptographic primitives, including the R-MAC scheme, the SHA-1 and MD2 hash functions, and a couple of block ciphers: DES, DFC, IDEA, ICE, LOKI, MISTY, RC2, RC5, RC6, SC2000, Skipjack, Square and SAFER. Knudsen was involved in designing some ciph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Message Authentication Code
In cryptography, a message authentication code (MAC), sometimes known as a ''tag'', is a short piece of information used for authenticating a message. In other words, to confirm that the message came from the stated sender (its authenticity) and has not been changed. The MAC value protects a message's data integrity, as well as its authenticity, by allowing verifiers (who also possess the secret key) to detect any changes to the message content. Terminology The term message integrity code (MIC) is frequently substituted for the term ''MAC'', especially in communications to distinguish it from the use of the latter as ''media access control address'' (''MAC address''). However, some authors use MIC to refer to a message digest, which aims only to uniquely but opaquely identify a single message. RFC 4949 recommends avoiding the term ''message integrity code'' (MIC), and instead using ''checksum'', ''error detection code'', '' hash'', ''keyed hash'', ''message authentication code'', ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cryptography
Cryptography, or cryptology (from grc, , translit=kryptós "hidden, secret"; and ''graphein'', "to write", or ''-logia'', "study", respectively), is the practice and study of techniques for secure communication in the presence of adversarial behavior. More generally, cryptography is about constructing and analyzing protocols that prevent third parties or the public from reading private messages. Modern cryptography exists at the intersection of the disciplines of mathematics, computer science, information security, electrical engineering, digital signal processing, physics, and others. Core concepts related to information security ( data confidentiality, data integrity, authentication, and non-repudiation) are also central to cryptography. Practical applications of cryptography include electronic commerce, chip-based payment cards, digital currencies, computer passwords, and military communications. Cryptography prior to the modern age was effectively synonymo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Confusion And Diffusion
In cryptography, confusion and diffusion are two properties of the operation of a secure cipher identified by Claude Shannon in his 1945 classified report ''A Mathematical Theory of Cryptography'.'' These properties, when present, work to thwart the application of statistics and other methods of cryptanalysis. These concepts are also important in the design of secure hash functions and pseudorandom number generators where decorrelation of the generated values is the main feature. Definition Confusion Confusion means that each binary digit (bit) of the ciphertext should depend on several parts of the key, obscuring the connections between the two. The property of confusion hides the relationship between the ciphertext and the key. This property makes it difficult to find the key from the ciphertext and if a single bit in a key is changed, the calculation of most or all of the bits in the ciphertext will be affected. Confusion increases the ambiguity of ciphertext and it is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exponentiation
Exponentiation is a mathematical operation, written as , involving two numbers, the '' base'' and the ''exponent'' or ''power'' , and pronounced as " (raised) to the (power of) ". When is a positive integer, exponentiation corresponds to repeated multiplication of the base: that is, is the product of multiplying bases: b^n = \underbrace_. The exponent is usually shown as a superscript to the right of the base. In that case, is called "''b'' raised to the ''n''th power", "''b'' (raised) to the power of ''n''", "the ''n''th power of ''b''", "''b'' to the ''n''th power", or most briefly as "''b'' to the ''n''th". Starting from the basic fact stated above that, for any positive integer n, b^n is n occurrences of b all multiplied by each other, several other properties of exponentiation directly follow. In particular: \begin b^ & = \underbrace_ \\[1ex] & = \underbrace_ \times \underbrace_ \\[1ex] & = b^n \times b^m \end In other words, when multiplying a base raised to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
