Areas of application for encrypted communication
Encryption is used for all conceivable forms of online communication. Users can chat, talk to each other, transfer files or carry out banking transactions in encrypted form. Some of the most common use cases for encrypted communication can be found here.
Every day, millions of e-mails are sent around the world via the Internet. The senders and recipients use a wide variety of e-mail programs for this purpose. To send the message, the e-mail providers behind them in turn use different nodes on the Web, where the e-mail is navigated and forwarded until it reaches the receiving e-mail program. On this route in the – not generally encrypted – Internet, the e-mail can then potentially be read along.
Internet telephony/VoIP – encrypted phone calls
Internet calls can be encrypted using the Secure Real-Time Transport Protocol (SRTP). This is the encrypted variant of the RTP protocol, which is responsible for data transport in Voice over IP connections. However, not all providers of Internet telephony support SRTP. To establish an encrypted connection, the terminals of the call participants must also be able to handle SRTP. We therefore recommend that you activate SRTP, if necessary and possible, both in the configuration interface of the provider and in the terminal device or telephony software. There are also VoIP systems that use encryption similar to that of browsers. It makes sense to combine this TLS encryption with SRTP so that the key exchange for SRTP is also encrypted. In addition, there are Internet telephony providers who have developed their own security and encryption mechanisms and only offer these to their own customers.
Virtual Private Networks (VPN) – encrypted connection
Virtual private networks drill tunnels through the Internet in the figurative sense. The communication between the participants of such a network is separated from all other data packets through this tunnel. VPN operators often use encryption to make communication tap-proof and protect it from manipulation. End points of a VPN can be computers, but also smartphones or routers. For example, a notebook user can log into a public WLAN and connect to his company’s VPN via it. From then on, they can exchange encrypted information with the company server.
Many home routers now also offer VPN functions. Owners of such devices can connect to the home network while on the move via an encrypted channel.
Browser – encrypted surfing
Most users certainly come into contact with encryption when surfing the Internet – even if they notice least of all here. It is often said that when doing banking transactions, for example, you should make sure that the website address begins with https://. This means nothing other than that the connection is encrypted. The methods used are called SSL and TLS. This encryption does not need to be activated separately, it takes place completely in the background.
Encrypting chats and conversations
Mobile phone calls and SMS are only encrypted between the smartphone and the mobile phone cell concerned. For smartphones and tablets, however, apps are available that handle messages and voice communication via the Internet connection. Depending on the application, the messages can also be encrypted, provided that both communication partners use the same app.
But how does it work?, you ask.
The complicated mode of operation simply explained
Those who use encrypted communication should know a little about the basics on which the technology is based. Understand the difference between symmetric and asymmetric encryption and learn why a key pair always includes a public and a private key.
Simple but efficient: Symmetric encryption relies on the sender and recipient of a secret message using the same key. Anyone who has this key can therefore decrypt the message – even if he or she is not allowed to read it.
Elaborate but clear: Asymmetric encryption eliminates the problem of distributing secret keys. However, asymmetric encryption methods require far more computing power than symmetric methods for encrypting and decrypting the transmitted data. In practice, therefore, asymmetric methods are only used to distribute secret symmetric keys. Furthermore, the problem of a tamper-proof distribution of public keys remains.
The asymmetrical method is less suitable for encrypting large amounts of data, since it is much slower than the symmetrical method. Therefore, in practice the advantages of both variants are combined as hybrid encryption. The data to be protected is encrypted using a fast symmetric method and only the key used for this purpose is then sent encrypted using the asymmetric method.
PKI and digital signature
Keys with fingerprints: With a public key infrastructure and digital signatures, it can be ensured that messages are exchanged between the correct senders and recipients and are not manipulated in transit.