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Post Office Protocol
In computing, the Post Office Protocol (POP) is an application-layer Internet standard protocol used by e-mail clients to retrieve e-mail from a mail server. POP version 3 (POP3) is the version in common use, and along with IMAP the most common protocols for email retrieval. Purpose The Post Office Protocol provides access via an Internet Protocol (IP) network for a user client application to a mailbox (''maildrop'') maintained on a mail server. The protocol supports download and delete operations for messages. POP3 clients connect, retrieve all messages, store them on the client computer, and finally delete them from the server. This design of POP and its procedures was driven by the need of users having only temporary Internet connections, such as dial-up access, allowing these users to retrieve e-mail when connected, and subsequently to view and manipulate the retrieved messages when offline. POP3 clients also have an option to leave mail on the server after download. By con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Application Layer
An application layer is an abstraction layer that specifies the shared communications protocols and interface methods used by hosts in a communications network. An ''application layer'' abstraction is specified in both the Internet Protocol Suite (TCP/IP) and the OSI model. Although both models use the same term for their respective highest-level layer, the detailed definitions and purposes are different. Internet protocol suite In the Internet protocol suite, the application layer contains the communications protocols and interface methods used in process-to-process communications across an Internet Protocol (IP) computer network. The application layer only standardizes communication and depends upon the underlying transport layer protocols to establish host-to-host data transfer channels and manage the data exchange in a client–server or peer-to-peer networking model. Though the TCP/IP application layer does not describe specific rules or data formats that applications mu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Joyce K
Joyce may refer to: People * Joyce (name), list of people and fictional characters with the given name or surname * Joyce, (born 1948), Brazilian singer-songwriter * James Joyce (1882–1941), Irish modernist writer Places * Joyce, Washington, an unincorporated community in the United States * Mount Joyce, Victoria Land, Antarctica * Joyce Peak, Ross Island, off the coast of Victoria Land * Joyce Glacier, Victoria Land * Lake Joyce, Victoria Land * Joyce Country, a region in counties Galway and Mayo in Ireland * 5418 Joyce, a main-belt asteroid Business * Joyce, house brand of Hong Kong company Joyce Boutique * JB Joyce & Co, an English clockmaker * Joyces 365, a supermarket chain based in Galway, Ireland * Amstrad PCW personal computer, sold under license in Europe as the "Joyce" Other uses * Hurricane Joyce (other), multiple storms * USS ''Joyce'' (DE-317), a destroyer escort that served in World War II * Joyce (programming language) * Joyce Theater, in the Manhat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shared Secret
In cryptography, a shared secret is a piece of data, known only to the parties involved, in a secure communication. This usually refers to the key of a symmetric cryptosystem. The shared secret can be a password, a passphrase, a big number, or an array of randomly chosen bytes. The shared secret is either shared beforehand between the communicating parties, in which case it can also be called a pre-shared key, or it is created at the start of the communication session by using a key-agreement protocol, for instance using public-key cryptography such as Diffie–Hellman or using symmetric-key cryptography such as Kerberos. The shared secret can be used for authentication (for instance when logging into a remote system) using methods such as challenge–response or it can be fed to a key derivation function to produce one or more keys to use for encryption and/or MACing of messages. To make unique session and message keys the shared secret is usually combined with an i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Replay Attack
A replay attack (also known as a repeat attack or playback attack) is a form of network attack in which valid data transmission is maliciously or fraudulently repeated or delayed. This is carried out either by the originator or by an adversary who intercepts the data and re-transmits it, possibly as part of a spoofing attack by IP packet substitution. This is one of the lower-tier versions of a man-in-the-middle attack. Replay attacks are usually passive in nature. Another way of describing such an attack is: "an attack on a security protocol using a replay of messages from a different context into the intended (or original and expected) context, thereby fooling the honest participant(s) into thinking they have successfully completed the protocol run." Example Suppose Alice wants to prove her identity to Bob. Bob requests her password as proof of identity, which Alice dutifully provides (possibly after some transformation like hashing, or even salting, the password); meanwhil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cryptographic Hash Function
A cryptographic hash function (CHF) is a hash algorithm (a map of an arbitrary binary string to a binary string with fixed size of n bits) that has special properties desirable for cryptography: * the probability of a particular n-bit output result (hash value) for a random input string ("message") is 2^ (like for any good hash), so the hash value can be used as a representative of the message; * finding an input string that matches a given hash value (a ''pre-image'') is unfeasible, unless the value is selected from a known pre-calculated dictionary (" rainbow table"). The ''resistance'' to such search is quantified as security strength, a cryptographic hash with n bits of hash value is expected to have a ''preimage resistance'' strength of n bits. A ''second preimage'' resistance strength, with the same expectations, refers to a similar problem of finding a second message that matches the given hash value when one message is already known; * finding any pair of different messa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kerberized
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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Project Athena
Project Athena was a joint project of MIT, Digital Equipment Corporation, and IBM to produce a campus-wide distributed computing environment for educational use. It was launched in 1983, and research and development ran until June 30, 1991. , Athena is still in production use at MIT. It works as software (currently a set of Debian packages) that makes a machine a thin client, that will download educational applications from the MIT servers on demand. Project Athena was important in the early history of desktop and distributed computing. It created the X Window System, Kerberos, and Zephyr Notification Service. It influenced the development of thin computing, LDAP, Active Directory, and instant messaging. Description Leaders of the $50 million, five-year project at MIT included Michael Dertouzos, director of the Laboratory for Computer Science; Jerry Wilson, dean of the School of Engineering; and Joel Moses, head of the Electrical Engineering and Computer Science departme ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Massachusetts Institute Of Technology
The Massachusetts Institute of Technology (MIT) is a private land-grant research university in Cambridge, Massachusetts. Established in 1861, MIT has played a key role in the development of modern technology and science, and is one of the most prestigious and highly ranked academic institutions in the world. Founded in response to the increasing industrialization of the United States, MIT adopted a European polytechnic university model and stressed laboratory instruction in applied science and engineering. MIT is one of three private land grant universities in the United States, the others being Cornell University and Tuskegee University. The institute has an urban campus that extends more than a mile (1.6 km) alongside the Charles River, and encompasses a number of major off-campus facilities such as the MIT Lincoln Laboratory, the Bates Center, and the Haystack Observatory, as well as affiliated laboratories such as the Broad and Whitehead Institutes. , 98 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Simple Authentication And Security Layer
Simple Authentication and Security Layer (SASL) is a framework for authentication and data security in Internet protocols. It decouples authentication mechanisms from application protocols, in theory allowing any authentication mechanism supported by SASL to be used in any application protocol that uses SASL. Authentication mechanisms can also support ''proxy authorization'', a facility allowing one user to assume the identity of another. They can also provide a ''data security layer'' offering ''data integrity'' and ''data confidentiality'' services. DIGEST-MD5 provides an example of mechanisms which can provide a data-security layer. Application protocols that support SASL typically also support Transport Layer Security (TLS) to complement the services offered by SASL. John Gardiner Myers wrote the original SASL specification (RFC 2222) in 1997. In 2006, that document was replaced by RFC 4422 authored by Alexey Melnikov and Kurt D. Zeilenga. SASL, as defined by RFC 4422 is an IETF ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Authentication
Authentication (from ''authentikos'', "real, genuine", from αὐθέντης ''authentes'', "author") is the act of proving an assertion, such as the identity of a computer system user. In contrast with identification, the act of indicating a person or thing's identity, authentication is the process of verifying that identity. It might involve validating personal identity documents, verifying the authenticity of a website with a digital certificate, determining the age of an artifact by carbon dating, or ensuring that a product or document is not counterfeit. Methods Authentication is relevant to multiple fields. In art, antiques, and anthropology, a common problem is verifying that a given artifact was produced by a certain person or in a certain place or period of history. In computer science, verifying a user's identity is often required to allow access to confidential data or systems. Authentication can be considered to be of three types: The first type of authe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rlogin
The Berkeley r-commands are a suite of computer programs designed to enable users of one Unix system to log in or issue commands to another Unix computer via TCP/IP computer network. The r-commands were developed in 1982 by the Computer Systems Research Group at the University of California, Berkeley, based on an early implementation of TCP/IP (the protocol stack of the Internet). The CSRG incorporated the r-commands into their Unix operating system, the Berkeley Software Distribution (BSD). The r-commands premiered in BSD v4.1. Among the programs in the suite are: (remote copy), (remote execution), (remote login), (remote shell), , , and (remote who). The r-commands were a significant innovation, and became ''de facto'' standards for Unix operating systems. With wider public adoption of the Internet, their inherent security vulnerabilities became a problem, and beginning with the development of Secure Shell protocols and applications in 1995, its adoption entirely suppla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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