Private chat in Skype
In the new version of Skype, a platform-independent solution for exchanging text messages and IP telephony, the function of end-to-end encryption in private chats has been added. The new feature is available in applications for mobile platforms iOS and Android, as well as desktop Windows, macOS and Linux.
A feature of end-to-end encryption is that encryption keys are only known to two communicating subscribers, so that third parties can not access their correspondence or can eavesdrop on a conversation, even before the content is intercepted in encrypted form.
Skype encryption is provided by the signal protocol originally developed by the Open Whisper Systems non-profit organization for its own courier with the same name, open source, which some experts consider to be one of the safest publicly available solutions. For example Edward Snowden (Edward Snowden), a former CIA official who was prosecuted by the US authorities, spoke positively about Signal.
How it works
To start a conversation whose content is encrypted, go to the other person's profile in the contacts list and press the & # 39; Start a private conversation & # 39; click. After this, the selected user receives an invitation to participate in the conversation with which you must agree. From the moment the invitation is accepted, the entire correspondence history is encrypted and only accessible to the user and his discussion partner, bypassing the Skype cloud that stores correspondence from regular chat rooms and groups. According to a similar principle, secret chat rooms are used in the "scandalous" messenger of Telegram Pavel Durov.
The interlocutor must confirm his wish to start a private conversation
There are some restrictions regarding only encrypted Skype chats: for example, a user can participate in a single personal conversation at the same time and the message history is only available on the device that initiated the call.
About coding in previous versions of Skype
As mentioned on the official website of Skype support, voice information, video, files and text messages are previously encrypted. The exception was voice calls to mobile and fixed telephones – in such cases Skype could not and does not offer encryption on the site from the telephone line to the subscriber of the fixed line. Thus, in the case of a conference call, in which several participants use Skype and at least one mobile phone, such a call is not reliably protected from interception.
To protect instant messages in cloud (group) chats, TLS (Transport layer security) is used, with asymmetric encryption for authentication and symmetric for privacy of messages. Personal correspondence between two subscribers (this method is still used by default) is encrypted using the symmetric algorithm of block encryption AES (Envanced Encryption Standard – "advanced encryption standard"), accepted as standard by the US government.
Voice messages are also encrypted before they are sent via the communication channel. After listening to the user of such a message, it is stored on his device in an unencrypted form.
In mid-January 2018 it was announced that the end-to-end encryption of Skype was being tested, providing a much higher level of privacy protection for private conversations. At that time, such functionality already included Apple iMessage, Facebook Messenger, Telegram, WhatsApp and others.