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CipherSaber
CipherSaber is a simple symmetric encryption Protocol (computing), protocol based on the RC4 stream cipher. Its goals are both technical and politics, political: it gives reasonably strong protection of message confidentiality, yet it's designed to be simple enough that even novice programmers can memorize the algorithm and implement it from scratch. According to the designer, a CipherSaber version in the QBASIC programming language takes just sixteen lines of code. Its political aspect is that because it's so simple, it can be reimplemented anywhere at any time, and so it provides a way for users to communicate privately even if government or other controls make distribution of normal cryptographic software completely impossible. History and purpose CipherSaber was invented by Arnold Reinhold to keep strong cryptography in the hands of the public. Many governments have implemented legal restrictions on who can use cryptography, and many more have proposed them. By publicizi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Initialization Vector
In cryptography, an initialization vector (IV) or starting variable is an input to a cryptographic primitive being used to provide the initial state. The IV is typically required to be random or pseudorandom, but sometimes an IV only needs to be unpredictable or unique. Randomization is crucial for some encryption schemes to achieve semantic security, a property whereby repeated usage of the scheme under the same cryptographic key, key does not allow an attacker to infer relationships between (potentially similar) segments of the encrypted message. For block ciphers, the use of an IV is described by the Block cipher mode of operation, modes of operation. Some cryptographic primitives require the IV only to be non-repeating, and the required randomness is derived internally. In this case, the IV is commonly called a cryptographic nonce, nonce (a number used only once), and the primitives (e.g. Block_cipher_mode_of_operation#CBC, CBC) are considered ''stateful'' rather than ''randomiz ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Symmetric Encryption
Symmetric-key algorithms are algorithms for cryptography that use the same cryptographic keys for both the encryption of plaintext and the decryption of ciphertext. The keys may be identical, or there may be a simple transformation to go between the two keys. The keys, in practice, represent a shared secret between two or more parties that can be used to maintain a private information link. The requirement that both parties have access to the secret key is one of the main drawbacks of symmetric-key encryption, in comparison to public-key encryption (also known as asymmetric-key encryption). However, symmetric-key encryption algorithms are usually better for bulk encryption. With exception of the one-time pad they have a smaller key size, which means less storage space and faster transmission. Due to this, asymmetric-key encryption is often used to exchange the secret key for symmetric-key encryption. Types Symmetric-key encryption can use either stream ciphers or block ciphers. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MIME
A mime artist, or simply mime (from Greek language, Greek , , "imitator, actor"), is a person who uses ''mime'' (also called ''pantomime'' outside of Britain), the acting out of a story through body motions without the use of speech, as a theatrical medium or as a performance art. In earlier times, in English, such a performer would typically be referred to as a mummer. Miming is distinguished from silent comedy, in which the artist is a character in a film or skit without sound. Jacques Copeau, strongly influenced by Commedia dell'arte and Japanese Noh theatre, used masks in the training of his actors. His pupil Étienne Decroux was highly influenced by this, started exploring and developing the possibilities of mime, and developed corporeal mime into a highly sculptural form, taking it outside the realms of naturalism. Jacques Lecoq contributed significantly to the development of mime and physical theatre with his training methods. As a result of this, the practice of mime h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IDG Books
International Data Group (IDG, Inc.) is an American market intelligence and demand generation company focused on the technology industry. IDG, Inc.'s mission is centered around supporting the technology industry through research, data, marketing technology, and insights that help create and sustain relationships between businesses. IDG, Inc. is wholly owned by Blackstone and is led by Genevieve Juillard, who was appointed CEO of the company in 2023. Juillard serves on IDG, Inc.'s leadership team along with IDC President Crawford Del Prete and IDG, Inc.'s Chief Financial Officer Tiziana Figliolia. IDG, Inc. is headquartered in Needham, Massachusetts and is the parent company of both International Data Corporation (IDC) and Foundry (formerly IDG Communications). History International Data Group was initially founded as International Data Corporation (IDC) in 1964 by Patrick Joseph McGovern, shortly after he had graduated from the Massachusetts Institute of Technology (MIT). ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Steganography
Steganography ( ) is the practice of representing information within another message or physical object, in such a manner that the presence of the concealed information would not be evident to an unsuspecting person's examination. In computing/electronic contexts, a computer file, message, image, or video is concealed within another file, message, image, or video. Generally, the hidden messages appear to be (or to be part of) something else: images, articles, shopping lists, or some other cover text. For example, the hidden message may be in invisible ink between the visible lines of a private letter. Some implementations of steganography that lack a formal shared secret are forms of security through obscurity, while key-dependent steganographic schemes try to adhere to Kerckhoffs's principle. The word ''steganography'' comes from Greek ''steganographia'', which combines the words ''steganós'' (), meaning "covered or concealed", and ''-graphia'' () meaning "writing". The fir ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Traffic Analysis
Traffic analysis is the process of intercepting and examining messages in order to deduce information from patterns in communication. It can be performed even when the messages are encrypted. In general, the greater the number of messages observed, the greater information be inferred. Traffic analysis can be performed in the context of military intelligence, counter-intelligence, or pattern-of-life analysis, and is also a concern in computer security. Traffic analysis tasks may be supported by dedicated computer software programs. Advanced traffic analysis techniques which may include various forms of social network analysis. Traffic analysis has historically been a vital technique in cryptanalysis, especially when the attempted crack depends on successfully seeding a known-plaintext attack, which often requires an inspired guess based on how specific the operational context might likely influence what an adversary communicates, which may be sufficient to establish a short cr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diceware
Diceware is a method for creating passphrases, passwords, and other cryptographic variables using ordinary dice as a hardware random number generator. For each word in the passphrase, five rolls of a six-sided die are required. The numbers from 1 to 6 that come up in the rolls are assembled as a five-digit number, e.g. ''43146''. That number is then used to look up a word in a cryptographic word list. In the original Diceware list ''43146'' corresponds to ''munch''. By generating several words in sequence, a lengthy passphrase can thus be constructed randomly. A Diceware word list is any list of unique words, preferably ones the user will find easy to spell and to remember. The contents of the word list do not have to be protected or concealed in any way, as the security of a Diceware passphrase is in the number of words selected, and the number of words each selected word could be taken from. Lists have been compiled for several languages, including Basque, Bulgarian, Cat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Random
In common usage, randomness is the apparent or actual lack of definite pattern or predictability in information. A random sequence of events, symbols or steps often has no order and does not follow an intelligible pattern or combination. Individual random events are, by definition, unpredictable, but if there is a known probability distribution, the frequency of different outcomes over repeated events (or "trials") is predictable.Strictly speaking, the frequency of an outcome will converge almost surely to a predictable value as the number of trials becomes arbitrarily large. Non-convergence or convergence to a different value is possible, but has probability zero. Consistent non-convergence is thus evidence of the lack of a fixed probability distribution, as in many evolutionary processes. For example, when throwing two dice, the outcome of any particular roll is unpredictable, but a sum of 7 will tend to occur twice as often as 4. In this view, randomness is not haphaza ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Entropy (information Theory)
In information theory, the entropy of a random variable quantifies the average level of uncertainty or information associated with the variable's potential states or possible outcomes. This measures the expected amount of information needed to describe the state of the variable, considering the distribution of probabilities across all potential states. Given a discrete random variable X, which may be any member x within the set \mathcal and is distributed according to p\colon \mathcal\to[0, 1], the entropy is \Eta(X) := -\sum_ p(x) \log p(x), where \Sigma denotes the sum over the variable's possible values. The choice of base for \log, the logarithm, varies for different applications. Base 2 gives the unit of bits (or "shannon (unit), shannons"), while base Euler's number, ''e'' gives "natural units" nat (unit), nat, and base 10 gives units of "dits", "bans", or "Hartley (unit), hartleys". An equivalent definition of entropy is the expected value of the self-information of a v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dictionary Attack
In cryptanalysis and computer security, a dictionary attack is an attack using a restricted subset of a keyspace to defeat a cipher or authentication mechanism by trying to determine its decryption key or passphrase, sometimes trying thousands or millions of likely possibilities often obtained from lists of past security breaches. Technique A dictionary attack is based on trying all the strings in a pre-arranged listing. Such attacks originally used words found in a dictionary (hence the phrase ''dictionary attack''); however, now there are much larger lists available on the open Internet containing hundreds of millions of passwords recovered from past data breaches. There is also cracking software that can use such lists and produce common variations, such as substituting numbers for similar-looking letters. A dictionary attack tries only those possibilities which are deemed most likely to succeed. Dictionary attacks often succeed because many people have a tendency to choose s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RSA (cryptosystem)
The RSA (Rivest–Shamir–Adleman) cryptosystem is a public-key cryptosystem, one of the oldest widely used for secure data transmission. The initialism "RSA" comes from the surnames of Ron Rivest, Adi Shamir and Leonard Adleman, who publicly described the algorithm in 1977. An equivalent system was developed secretly in 1973 at Government Communications Headquarters (GCHQ), the British signals intelligence agency, by the English mathematician Clifford Cocks. That system was declassified in 1997. In a public-key cryptosystem, the encryption key is public and distinct from the decryption key, which is kept secret (private). An RSA user creates and publishes a public key based on two large prime numbers, along with an auxiliary value. The prime numbers are kept secret. Messages can be encrypted by anyone via the public key, but can only be decrypted by someone who knows the private key. The security of RSA relies on the practical difficulty of factoring the product o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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, 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 (TLS), SSH, S/MIME, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
