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DVB-CSA
The Common Scrambling Algorithm (CSA) is the encryption algorithm used in the Digital Video Broadcasting, DVB digital television broadcasting for encrypting video coding, video streams. CSA was specified by ETSI and adopted by the DVB consortium in May 1994. It is being succeeded by CSA3, based on a combination of 128-bit Advanced Encryption Standard, AES and a confidential block cipher, XRC. However, CSA3 is not yet in any significant use, so CSA continues to be the dominant cipher for protecting DVB broadcasts. History CSA was largely kept secret until 2002. The patent papers gave some hints, but important details, like the layout of the so-called S-boxes, remained secret. Without these, free implementations of the algorithm was not possible. Initially, CSA was to remain implemented in hardware only, making it difficult to Reverse engineering, reverse engineer existing implementations. In 2002 FreeDec was released, implementing CSA in software. Though released as executable, bin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Card Sharing
Card sharing, also known as control word sharing, is a method of allowing multiple clients or digital television receivers to access a subscription television network with only one valid subscription card. This is achieved by electronically sharing a part of the legitimate conditional access smart card's output data, enabling all recipients to gain simultaneous access to scrambled Digital Video Broadcasting, DVB streams, held on the encrypted television network. Typically, a legitimate smart card is attached to a host digital television receiver, which is equipped with software to share the decrypted 64-bit "control word" key over a computer network, such as the Internet. Once a client receives this key, they can decrypt the encrypted content as though they were using their own subscription card. The theory of card sharing as a potential attack vector on pay TV encryption was provided in the book ''European Scrambling Systems'' by John McCormac in 1996; leading to the term "McCorm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digital Video Broadcasting
Digital Video Broadcasting (DVB) is a set of international open standards for digital television. DVB standards are maintained by the DVB Project, an international industry consortium, and are published by a Joint Technical Committee (JTC) of the European Telecommunications Standards Institute (ETSI), European Committee for Electrotechnical Standardization (CENELEC) and European Broadcasting Union (EBU). Transmission DVB systems distribute data using a variety of approaches, including: * Satellite: DVB-S, DVB-DSNG, DVB-S2, DVB-S2X and DVB-SH ** DVB-SMATV for distribution via SMATV * Cable: DVB-C, DVB-C2 * Terrestrial television: DVB-T, DVB-T2 ** Digital terrestrial television for handhelds: DVB-H, DVB-SH * Microwave: using DTT ( DVB-MT), the MMDS ( DVB-MC), and/or MVDS standards ( DVB-MS) These standards define the physical layer and data link layer of the distribution system. Devices interact with the physical layer via a synchronous parallel interface ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Encryption Algorithm
In cryptography, encryption (more specifically, encoding) is the process of transforming information in a way that, ideally, only authorized parties can decode. This process converts the original representation of the information, known as plaintext, into an alternative form known as ciphertext. Despite its goal, encryption does not itself prevent interference but denies the intelligible content to a would-be interceptor. For technical reasons, an encryption scheme usually uses a pseudo-random encryption key generated by an algorithm. It is possible to decrypt the message without possessing the key but, for a well-designed encryption scheme, considerable computational resources and skills are required. An authorized recipient can easily decrypt the message with the key provided by the originator to recipients but not to unauthorized users. Historically, various forms of encryption have been used to aid in cryptography. Early encryption techniques were often used in military mes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rainbow Table
A rainbow table is a precomputed table for caching the outputs of a cryptographic hash function, usually for cracking password hashes. Passwords are typically stored not in plain text form, but as hash values. If such a database of hashed passwords falls into the hands of attackers, they can use a precomputed rainbow table to recover the plaintext passwords. A common defense against this attack is to compute the hashes using a key derivation function that adds a "salt" to each password before hashing it, with different passwords receiving different salts, which are stored in plain text along with the hash. Rainbow tables are a practical example of a space–time tradeoff: they use less computer processing time and more storage than a brute-force attack which calculates a hash on every attempt, but more processing time and less storage than a simple table that stores the hash of every possible password. Rainbow tables were invented by Philippe Oechslin as an application of an ea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brute Force Attack
In cryptography, a brute-force attack or exhaustive key search is a cryptanalytic attack that consists of an attacker submitting many possible Key (cryptography), keys or passwords with the hope of eventually guessing correctly. This strategy can theoretically be used to break any form of encryption that is not information-theoretically secure. However, in a properly designed cryptosystem the chance of successfully guessing the key is negligible. When Password cracking, cracking passwords, this method is very fast when used to check all short passwords, but for longer passwords other methods such as the dictionary attack are used because a brute-force search takes too long. Longer passwords, passphrases and keys have more possible values, making them exponentially more difficult to crack than shorter ones due to diversity of characters. Brute-force attacks can be made less effective by Obfuscation (software), obfuscating the data to be encoded making it more difficult for an att ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Known-plaintext Attack
The known-plaintext attack (KPA) is an attack model for cryptanalysis where the attacker has access to both the plaintext (called a crib) and its encrypted version (ciphertext). These can be used to reveal secret keys and code books. The term "crib" originated at Bletchley Park, the British World War II decryption operation, where it was defined as: History The usage "crib" was adapted from a slang term referring to cheating (e.g., "I cribbed my answer from your test paper"). A "crib" originally was a literal or interlinear translation of a foreign-language text—usually a Latin or Greek text—that students might be assigned to translate from the original language. The idea behind a crib is that cryptologists were looking at incomprehensible ciphertext, but if they had a clue about some word or phrase that might be expected to be in the ciphertext, they would have a "wedge," a test to break into it. If their otherwise random attacks on the cipher managed to sometimes produce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
AVX2
Advanced Vector Extensions (AVX, also known as Gesher New Instructions and then Sandy Bridge New Instructions) are SIMD extensions to the x86 instruction set architecture for microprocessors from Intel and Advanced Micro Devices (AMD). They were proposed by Intel in March 2008 and first supported by Intel with the Sandy Bridge microarchitecture shipping in Q1 2011 and later by AMD with the Bulldozer microarchitecture shipping in Q4 2011. AVX provides new features, new instructions, and a new coding scheme. AVX2 (also known as Haswell New Instructions) expands most integer commands to 256 bits and introduces new instructions. They were first supported by Intel with the Haswell microarchitecture, which shipped in 2013. AVX-512 expands AVX to 512-bit support using a new EVEX prefix encoding proposed by Intel in July 2013 and first supported by Intel with the Knights Landing co-processor, which shipped in 2016. In conventional processors, AVX-512 was introduced with Skylak ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SIMD
Single instruction, multiple data (SIMD) is a type of parallel computer, parallel processing in Flynn's taxonomy. SIMD describes computers with multiple processing elements that perform the same operation on multiple data points simultaneously. SIMD can be internal (part of the hardware design) and it can be directly accessible through an instruction set architecture (ISA), but it should not be confused with an ISA. Such machines exploit Data parallelism, data level parallelism, but not Concurrent computing, concurrency: there are simultaneous (parallel) computations, but each unit performs exactly the same instruction at any given moment (just with different data). A simple example is to add many pairs of numbers together, all of the SIMD units are performing an addition, but each one has different pairs of values to add. SIMD is particularly applicable to common tasks such as adjusting the contrast in a digital image or adjusting the volume of digital audio. Most modern Cen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
S-boxes
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 nonlinear 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bit Slicing
Bit slicing is a technique for constructing a processor from modules of processors of smaller bit width, for the purpose of increasing the word length; in theory to make an arbitrary ''n''-bit central processing unit (CPU). Each of these component modules processes one bit field or "slice" of an operand. The grouped processing components would then have the capability to process the chosen full word-length of a given software design. Bit slicing more or less died out due to the advent of the microprocessor. Recently it has been used in arithmetic logic units (ALUs) for quantum computers and as a software technique, e.g. for cryptography in x86 CPUs. Operational details Bit-slice processors (BSPs) usually include 1-, 2-, 4-, 8- or 16-bit arithmetic logic unit (ALU) and control lines (including carry or overflow signals that are internal to the processor in non-bitsliced CPU designs). For example, two 4-bit ALU chips could be arranged side by side, with control ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
VideoGuard
VideoGuard (sometimes referred to simply as ''NDS''), produced by NDS, is a digital encryption system for use with conditional access television broadcasting. It is used on digital satellite television systems – some of which are operated by News Corporation, which owned about half (49%) of NDS until its sale to Cisco in 2012 (becoming Cisco Videoscape division). Since 2018 VideoGuard is improved and maintained by Synamedia (Cisco's spun-off company based on its former Videoscape division). Its two most widely used implementations are Sky in the United Kingdom and Ireland and DirecTV in the United States, the former of which launched the digital version of the system in 1998. History Since the majority of content provided by companies like BSkyB requires subscription, VideoGuard protects that content by encrypting both standard subscription channels and pay-per-view movies and events. Access flags can be downloaded to the subscriber's card either over the air (via 'hidden' d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
