For data transfer via Skype uses P2P-architecture, unlike other programs of IP-telephony. All users of Skype software distributed between the computers of network users so that it becomes possible to scale the network to an enormous size. Currently there are over 100 million users of Skype, while online is about 15-25 millionov.Esche one of the features of Skype is the ability to route calls through other users’ computers. This allows users who are behind a NAT or firewall, connect to each other, but at the same time creates an additional burden on users’ computers directly connected to Internetu.Uchetnye accounts and a copy of their contact lists stored on the server for identification, which is a central element of Skype.
The central server is required to establish a connection. After installing the communication computers directly send voice data to each. If the computers are connected to the same local network, talk on Skype-connection is possible even if you disable the Internet. Interrupt it can only fail on the local network itself or polzovatel.Kachestvo sound Skype does not yield quality of regular telephone line.This is achieved with a codec G.729 (8 kHz), Silk (8-24 kHz) and G.711, as well as satisfactory through your Internet connection speed (30-60 kbit / s). AES-256 encrypted data for a connection between a PC. To send the key with AES-256 uses 1024-bit key RSA. Using RSA certificates certified public keys of users attempting to log into the system. VoIP-Skype is a closed protocol, it can only use the original software Skype.
Third-party programs access to its functions can be obtained using API. At the present time are not officially recorded no cases of interception or decryption of data in Skype, which causes great dissatisfaction among the security forces. However, there is information that in 2008 still managed to intercept the traffic law enforcement agencies of Austria. Similar information came from and Australian law enforcement agencies. Skype download for free and everyone can, which imposes a limit on the ban. Also, the possibility of listening to Skype said the Swiss authorities and the FSB.It is worth repeating that this information is not confirmed, and most likely to listen can only users’ computers, but not encrypted trafik.Chtoby use video calling, you need an Internet connection at speeds of 200 kbit / s and with a minimum clock speed of 1 GHz.