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Acrobits Softphone
Acrobits is a privately owned software development company creating VoIP Clients for mobile platforms, based in Prague, Czech Republic. Company history Acrobits was founded in November 2008, and builds mobile VoIP software with a polished user interface, supporting encrypted calls using SRTP/SDES and ZRTP, Google Voice integration, and the G.729 Annex A audio codec. In 2009 Acrobits Softphone was released on the iTunes App Store. The following year Acrobits released their SIP Client with business features, Groundwire. In early 2011 Acrobits Softphone was released on the Android Market. In 2010 Acrobits also launched a service allowing SIP providers to appear on the list of pre-configured providers in Acrobits Softphone. In 2012 Acrobits added video calls over WiFi support for the iOS version of its softphone. Acrobits Softphone Acrobits Softphone is a VoIP client which uses Session Initiation Protocol. Acrobits Softphone is the leading SIP Client on the App Store, featuring ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acrobits Groundwire
Acrobits is a privately owned software development company creating VoIP Clients for mobile platforms, based in Prague, Czech Republic. Company history Acrobits was founded in November 2008, and builds mobile VoIP software with a polished user interface, supporting encrypted calls using SRTP/SDES and ZRTP, Google Voice integration, and the G.729 Annex A audio codec. In 2009 Acrobits Softphone was released on the iTunes App Store. The following year Acrobits released their SIP Client with business features, Groundwire. In early 2011 Acrobits Softphone was released on the Android Market. In 2010 Acrobits also launched a service allowing SIP providers to appear on the list of pre-configured providers in Acrobits Softphone. In 2012 Acrobits added video calls over WiFi support for the iOS version of its softphone. Acrobits Softphone Acrobits Softphone is a VoIP client which uses Session Initiation Protocol. Acrobits Softphone is the leading SIP Client on the App Store, featuring ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
WikiProject Companies
A WikiProject, or Wikiproject, is a Wikimedia movement affinity group for contributors with shared goals. WikiProjects are prevalent within the largest wiki, Wikipedia, and exist to varying degrees within sister projects such as Wiktionary, Wikiquote, Wikidata, and Wikisource. They also exist in different languages, and translation of articles is a form of their collaboration. During the COVID-19 pandemic, CBS News noted the role of Wikipedia's WikiProject Medicine in maintaining the accuracy of articles related to the disease. Another WikiProject that has drawn attention is WikiProject Women Scientists, which was profiled by '' Smithsonian'' for its efforts to improve coverage of women scientists which the profile noted had "helped increase the number of female scientists on Wikipedia from around 1,600 to over 5,000". On Wikipedia Some Wikipedia WikiProjects are substantial enough to engage in cooperative activities with outside organizations relevant to the field at issue. For ex ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Man-in-the-middle Attack
In cryptography and computer security, a man-in-the-middle, monster-in-the-middle, machine-in-the-middle, monkey-in-the-middle, meddler-in-the-middle, manipulator-in-the-middle (MITM), person-in-the-middle (PITM) or adversary-in-the-middle (AiTM) attack is a cyberattack where the attacker secretly relays and possibly alters the communications between two parties who believe that they are directly communicating with each other, as the attacker has inserted themselves between the two parties. One example of a MITM attack is active eavesdropping, in which the attacker makes independent connections with the victims and relays messages between them to make them believe they are talking directly to each other over a private connection, when in fact the entire conversation is controlled by the attacker. The attacker must be able to intercept all relevant messages passing between the two victims and inject new ones. This is straightforward in many circumstances; for example, an attacker wit ... [...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] |
Phil Zimmermann
Philip R. Zimmermann (born 1954) is an American computer scientist and Cryptography, cryptographer. He is the creator of Pretty Good Privacy (PGP), the most widely used email encryption software in the world. He is also known for his work in VoIP encryption protocols, notably ZRTP and Zfone. Zimmermann is co-founder and Chief Scientist of the global encrypted communications firm Silent Circle (software), Silent Circle. Background He was born in Camden, New Jersey. Zimmermann received a B.S. degree in computer science from Florida Atlantic University in Boca Raton, Florida in 1978. In the 1980s, Zimmermann worked in Boulder, Colorado as a software engineer on the Nuclear Weapons Freeze Campaign as a military policy analyst. PGP In 1991, he wrote the popular Pretty Good Privacy (PGP) program, and made it available (together with its source code) through public FTP for download, the first widely available program implementing public-key cryptography. Shortly thereafter, it became a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transport Layer Security
Transport Layer Security (TLS) is a cryptographic protocol designed to provide communications security over a computer network. The protocol is widely used in applications such as email, instant messaging, and voice over IP, but its use in securing HTTPS remains the most publicly visible. The TLS protocol aims primarily to provide security, including privacy (confidentiality), integrity, and authenticity through the use of cryptography, such as the use of certificates, between two or more communicating computer applications. It runs in the presentation layer and is itself composed of two layers: the TLS record and the TLS handshake protocols. The closely related Datagram Transport Layer Security (DTLS) is a communications protocol providing security to datagram-based applications. In technical writing you often you will see references to (D)TLS when it applies to both versions. TLS is a proposed Internet Engineering Task Force (IETF) standard, first defined in 1999, and the c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Session Description Protocol
The Session Description Protocol (SDP) is a format for describing multimedia communication sessions for the purposes of announcement and invitation. Its predominant use is in support of streaming media applications, such as voice over IP (VoIP) and video conferencing. SDP does not deliver any media streams itself but is used between endpoints for negotiation of network metrics, media types, and other associated properties. The set of properties and parameters is called a ''session profile''. SDP is extensible for the support of new media types and formats. SDP was originally a component of the Session Announcement Protocol (SAP), but found other uses in conjunction with the Real-time Transport Protocol (RTP), the Real-time Streaming Protocol (RTSP), Session Initiation Protocol (SIP), and as a standalone protocol for describing multicast sessions. The IETF published the original specification as a Proposed Standard in April 1998. Revised specifications were released in 2006 (RFC ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SDES
SDES (Session Description Protocol Security Descriptions) for Media Streams is a way to negotiate the key for Secure Real-time Transport Protocol. It has been proposed for standardization to the IETF in July 2006 (see RFC khh.) How it works The keys are transported in the SDP attachment of a SIP message. That means, the SIP transport layer must make sure that no one else can see the attachment. This can be done by using TLS transport layer, or other methods like S/MIME. Using TLS assumes that the next hop in the SIP proxy chain can be trusted and it will take care about the security requirements of the request. The main advantage of this method is that it is extremely simple. The key exchange method has been picked up by several vendors already, even though some vendors do not use a secure mechanism to transport the key. This helps to get the critical mass of implementation to make this method the de facto standard. To illustrate this principle with an example, the phone sen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hash-based Message Authentication Code
In cryptography, an HMAC (sometimes expanded as either keyed-hash message authentication code or hash-based message authentication code) is a specific type of message authentication code (MAC) involving a cryptographic hash function and a secret cryptographic key. As with any MAC, it may be used to simultaneously verify both the data integrity and authenticity of a message. HMAC can provide authentication using a shared secret instead of using digital signatures with asymmetric cryptography. It trades off the need for a complex public key infrastructure by delegating the key exchange to the communicating parties, who are responsible for establishing and using a trusted channel to agree on the key prior to communication. Details Any cryptographic hash function, such as SHA-2 or SHA-3, may be used in the calculation of an HMAC; the resulting MAC algorithm is termed HMAC-X, where X is the hash function used (e.g. HMAC-SHA256 or HMAC-SHA3-512). The cryptographic strength of the H ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Advanced Encryption Standard
The Advanced Encryption Standard (AES), also known by its original name Rijndael (), is a specification for the encryption of electronic data established by the U.S. National Institute of Standards and Technology (NIST) in 2001. AES is a variant of the Rijndael block cipher developed by two Belgian cryptographers, Joan Daemen and Vincent Rijmen, who submitted a proposal to NIST during the AES selection process. Rijndael is a family of ciphers with different key and block sizes. For AES, NIST selected three members of the Rijndael family, each with a block size of 128 bits, but three different key lengths: 128, 192 and 256 bits. AES has been adopted by the U.S. government. It supersedes the Data Encryption Standard (DES), which was published in 1977. The algorithm described by AES is a symmetric-key algorithm, meaning the same key is used for both encrypting and decrypting the data. In the United States, AES was announced by the NIST as U.S. FIPS PUB 197 (FIPS 197) on Novemb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Secure Real-time Transport Protocol
The Secure Real-time Transport Protocol (SRTP) is a profile for Real-time Transport Protocol (RTP) intended to provide encryption, message authentication and integrity, and replay attack protection to the RTP data in both unicast and multicast applications. It was developed by a small team of Internet Protocol and cryptographic experts from Cisco and Ericsson. It was first published by the IETF in March 2004 as . Since RTP is accompanied by the RTP Control Protocol (RTCP) which is used to control an RTP session, SRTP has a sister protocol, called Secure RTCP (SRTCP); it securely provides the same functions to SRTP as the ones provided by RTCP to RTP. Utilization of SRTP or SRTCP is optional in RTP or RTCP applications; but even if SRTP or SRTCP are used, all provided features (such as encryption and authentication) are optional and can be separately enabled or disabled. The only exception is the message authentication feature which is indispensable and required when using SRTC ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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