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Designated Verifier Signature
A designated verifier signature is a signature scheme in which signatures can only be verified by a single, designated verifier, designated as part of the signature creation. Designated verifier signatures were first proposed in 1996 by Jakobsson Markus, Kazue Sako, and Russell Impagliazzo. Proposed as a way to combine authentication and off-the-record messages, designated verifier signatures allow authenticated, private conversations to take place. Unlike in undeniable signature scheme the protocol of verifying is non-interactive; i.e., the signer chooses the designated verifier (or the set of designated verifiers) in advance and does not take part in the verification process. See also * Non-repudiation * Undeniable signature An undeniable signature is a digital signature scheme which allows the signer to be selective to whom they allow to verify signatures. The scheme adds explicit signature repudiation, preventing a signer later refusing to verify a signature by omissi ... Re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digital Signature
A digital signature is a mathematical scheme for verifying the authenticity of digital messages or documents. A valid digital signature, where the prerequisites are satisfied, gives a recipient very high confidence that the message was created by a known sender (authenticity), and that the message was not altered in transit (integrity). Digital signatures are a standard element of most cryptographic protocol suites, and are commonly used for software distribution, financial transactions, contract management software, and in other cases where it is important to detect forgery or tampering. Digital signatures are often used to implement electronic signatures, which includes any electronic data that carries the intent of a signature, but not all electronic signatures use digital signatures. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Journalism Sourcing
In journalism, a source is a person, publication, or knowledge other record or document that gives timely information. Outside journalism, sources are sometimes known as "news sources". Examples of sources include but are not limited to official records, publications or broadcasts, officials in government or business, organizations or corporations, witnesses of crime, accidents or other events, and people involved with or affected by a news event or issue. According to Shoemaker (1996) and McQuail (1994), there are a multitude of factors that tend to condition the acceptance of sources as bona fide by investigative journalists. Reporters are expected to develop and cultivate sources, especially if they regularly cover a specific topic, known as a "beat". Beat reporters must, however, be cautious of becoming too close to their sources. Reporters often, but not always, give greater leeway to sources with little experience. For example, sometimes a person will say they don't want t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Undeniable Signature
An undeniable signature is a digital signature scheme which allows the signer to be selective to whom they allow to verify signatures. The scheme adds explicit signature repudiation, preventing a signer later refusing to verify a signature by omission; a situation that would devalue the signature in the eyes of the verifier. It was invented by David Chaum and Hans van Antwerpen in 1989. Overview In this scheme, a signer possessing a private key can publish a signature of a message. However, the signature reveals nothing to a recipient/verifier of the message and signature without taking part in either of two interactive protocols: * Confirmation protocol, which confirms that a candidate is a valid signature of the message issued by the signer, identified by the public key. * Disavowal protocol, which confirms that a candidate is not a valid signature of the message issued by the signer. The motivation for the scheme is to allow the signer to choose to whom signatures are verified. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Non-repudiation
Non-repudiation refers to a situation where a statement's author cannot successfully dispute its authorship or the validity of an associated contract. The term is often seen in a legal setting when the authenticity of a signature is being challenged. In such an instance, the authenticity is being "repudiated". For example, Mallory buys a cell phone for $100, writes a paper cheque as payment, and signs the cheque with a pen. Later, she finds that she can't afford it, and claims that the cheque is a forgery. The signature guarantees that only Mallory could have signed the cheque, and so Mallory's bank must pay the cheque. This is non-repudiation; Mallory cannot repudiate the cheque. In practice, pen-and-paper signatures aren't hard to forge, but digital signatures can be very hard to break. In security In general, ''non-repudiation'' involves associating actions or changes with a unique individual. For example, a secure area may use a key card access system where non-repudiation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Undeniable Signature
An undeniable signature is a digital signature scheme which allows the signer to be selective to whom they allow to verify signatures. The scheme adds explicit signature repudiation, preventing a signer later refusing to verify a signature by omission; a situation that would devalue the signature in the eyes of the verifier. It was invented by David Chaum and Hans van Antwerpen in 1989. Overview In this scheme, a signer possessing a private key can publish a signature of a message. However, the signature reveals nothing to a recipient/verifier of the message and signature without taking part in either of two interactive protocols: * Confirmation protocol, which confirms that a candidate is a valid signature of the message issued by the signer, identified by the public key. * Disavowal protocol, which confirms that a candidate is not a valid signature of the message issued by the signer. The motivation for the scheme is to allow the signer to choose to whom signatures are verified. ... [...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] |
