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Certificate Revocation
In cryptography, a certificate revocation list (or CRL) is "a list of digital certificates that have been revoked by the issuing certificate authority (CA) before their scheduled expiration date and should no longer be trusted". CRLs are no longer required by the CA/Browser forum, as alternate certificate revocation technologies (such as OCSP) are increasingly used instead. Nevertheless, CRLs are still widely used by the CAs. Revocation states There are two different states of revocation defined in RFC 5280: ; Revoked: A certificate is irreversibly revoked if, for example, it is discovered that the certificate authority (CA) had improperly issued a certificate, or if a private-key is thought to have been compromised. Certificates may also be revoked for failure of the identified entity to adhere to policy requirements, such as publication of false documents, misrepresentation of software behaviour, or violation of any other policy specified by the CA operator or its customer. The mo ... [...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] |
Symmetric Key Algorithm
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. 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. * Stream ciphers encrypt the digits ... [...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. In a public-key encryption system, anyone with a public key can encrypt a message, yielding a ciphertext, but only those who know the corresponding private key can decrypt the ciphertext to obtain the original message. For example, a journalist can publish the public key of an encryption key pair on a web site so that sources can send secret messages to the news organization in ciphertext. Only the journalist who knows the corresponding private key can decrypt the ciphertexts to obtain the sources' messages—an eavesdropp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Key Management
Key management refers to management of cryptographic keys in a cryptosystem. This includes dealing with the generation, exchange, storage, use, crypto-shredding (destruction) and replacement of keys. It includes cryptographic protocol design, key servers, user procedures, and other relevant protocols. Key management concerns keys at the user level, either between users or systems. This is in contrast to key scheduling, which typically refers to the internal handling of keys within the operation of a cipher. Successful key management is critical to the security of a cryptosystem. It is the more challenging side of cryptography in a sense that it involves aspects of social engineering such as system policy, user training, organizational and departmental interactions, and coordination between all of these elements, in contrast to pure mathematical practices that can be automated. Types of keys Cryptographic systems may use different types of keys, with some systems using more ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
OCSP
The Online Certificate Status Protocol (OCSP) is an Internet protocol used for obtaining the revocation status of an X.509 digital certificate. It is described in RFC 6960 and is on the Internet standards track. It was created as an alternative to certificate revocation lists (CRL), specifically addressing certain problems associated with using CRLs in a public key infrastructure (PKI). Messages communicated via OCSP are encoded in ASN.1 and are usually communicated over HTTP. The "request/response" nature of these messages leads to OCSP servers being termed ''OCSP responders''. Some web browsers (Firefox) use OCSP to validate HTTPS certificates, while others have disabled it. Most OCSP revocation statuses on the Internet disappear soon after certificate expiration. Comparison to CRLs * Since an OCSP response contains less data than a typical certificate revocation list (CRL), it puts less burden on network and client resources. * Since an OCSP response has less data to parse, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Certificate Server
In cryptography, a certificate authority or certification authority (CA) is an entity that stores, signs, and issues digital certificates. A digital certificate certifies the ownership of a public key by the named subject of the certificate. This allows others (relying parties) to rely upon signatures or on assertions made about the private key that corresponds to the certified public key. A CA acts as a trusted third party—trusted both by the subject (owner) of the certificate and by the party relying upon the certificate. The format of these certificates is specified by the X.509 or EMV standard. One particularly common use for certificate authorities is to sign certificates used in HTTPS, the secure browsing protocol for the World Wide Web. Another common use is in issuing identity cards by national governments for use in electronically signing documents. Overview Trusted certificates can be used to create secure connections to a server via the Internet. A certificate is e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Web Of Trust
In cryptography, a web of trust is a concept used in PGP, GnuPG, and other OpenPGP-compatible systems to establish the authenticity of the binding between a public key and its owner. Its decentralized trust model is an alternative to the centralized trust model of a public key infrastructure (PKI), which relies exclusively on a certificate authority (or a hierarchy of such). As with computer networks, there are many independent webs of trust, and any user (through their public key certificate) can be a part of, and a link between, multiple webs. The web of trust concept was first put forth by PGP creator Phil Zimmermann in 1992 in the manual for PGP version 2.0: Note the use of the word emergence in this context. The web of trust makes use of the concept of emergence. Operation of a web of trust All OpenPGP-compliant implementations include a certificate vetting scheme to assist with this; its operation has been termed a web of trust. OpenPGP certificates (which include on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trusted Third Party
In cryptography, a trusted third party (TTP) is an entity which facilitates interactions between two parties who both trust the third party; the Third Party reviews all critical transaction communications between the parties, based on the ease of creating fraudulent digital content. In TTP models, the relying parties use this trust to secure their own interactions. TTPs are common in any number of commercial transactions and in cryptographic digital transactions as well as cryptographic protocols, for example, a certificate authority (CA) would issue a digital certificate to one of the two parties in the next example. The CA then becomes the Trusted-Third-Party to that certificates issuance. Likewise transactions that need a third party recordation would also need a third-party repository service of some kind or another. 'Trusted' means that a system needs to be trusted to act in your interests, but it has the option (either at will or involuntarily) to act against your interests. ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Key Distribution Center
{{cleanup, date=November 2011 In cryptography, a key distribution center (KDC) is part of a cryptosystem intended to reduce the risks inherent in exchanging keys. KDCs often operate in systems within which some users may have permission to use certain services at some times and not at others. Security overview For instance, an administrator may have established a policy that only certain users may back up to tape. Many operating systems can control access to the tape facility via a "system service". If that system service further restricts the tape drive to operate only on behalf of users who can submit a service-granting ticket when they wish to use it, there remains only the task of distributing such tickets to the appropriately permitted users. If the ticket consists of (or includes) a key, one can then term the mechanism which distributes it a KDC. Usually, in such situations, the KDC itself also operates as a system service. Operation A typical operation with a KDC involves ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kerberos (protocol)
Kerberos () is a computer-network authentication protocol that works on the basis of ''tickets'' to allow nodes communicating over a non-secure network to prove their identity to one another in a secure manner. Its designers aimed it primarily at a client–server model, and it provides mutual authentication—both the user and the server verify each other's identity. Kerberos protocol messages are protected against eavesdropping and replay attacks. Kerberos builds on symmetric-key cryptography and requires a trusted third party, and optionally may use public-key cryptography during certain phases of authentication.RFC 4556, abstract. Kerberos uses UDP port 88 by default. The protocol was named after the character '' Kerberos'' (or ''Cerberus'') from Greek mythology, the ferocious three-headed guard dog of Hades. History and development Massachusetts Institute of Technology (MIT) developed Kerberos in 1988 to protect network services provided by Project Athena. The protocol is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
VeriSign
Verisign Inc. is an American company based in Reston, Virginia, United States that operates a diverse array of network infrastructure, including two of the Internet's thirteen root nameservers, the authoritative registry for the , , and generic top-level domains and the and country-code top-level domains, and the back-end systems for the , , and sponsored top-level domains. In 2010, Verisign sold its authentication business unit – which included Secure Sockets Layer (SSL) certificate, public key infrastructure (PKI), Verisign Trust Seal, and Verisign Identity Protection (VIP) services – to Symantec for $1.28 billion. The deal capped a multi-year effort by Verisign to narrow its focus to its core infrastructure and security business units. Symantec later sold this unit to DigiCert in 2017. On October 25, 2018, NeuStar, Inc. acquired VeriSign’s Security Service Customer Contracts. The acquisition effectively transferred Verisign Inc.’s Distributed Denial of Service ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digital Certificates
Digital usually refers to something using discrete digits, often binary digits. Technology and computing Hardware *Digital electronics, electronic circuits which operate using digital signals **Digital camera, which captures and stores digital images ***Digital versus film photography **Digital computer, a computer that handles information represented by discrete values **Digital recording, information recorded using a digital signal Socioeconomic phenomena *Digital culture, the anthropological dimension of the digital social changes * Digital divide, a form of economic and social inequality in access to or use of information and communication technologies * Digital economy, an economy based on computing and telecommunications resources Other uses in technology and computing * Digital data, discrete data, usually represented using binary numbers *Digital marketing, search engine & social media presence booster, usually represented using online visibility. * Digital media, media ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
