Encryption is a cryptographic method of converting information into a format that can only be interpreted by anyone who has the key to decipher the message. The science of cryptography, the encryption of messages, was invented in ancient times, but for a long time only military and diplomatic messages were encrypted. In the 20th century, cryptography has become widespread in business and economy, and with the advent of digital networks it became a part of everyday life. At the same time, the mission of cryptography expanded: besides encrypting messages, data and information protection, i.e. information security, have become a field where cryptography is applied. Network communication uses a variety of encryption procedures to ensure that messages are accessed only by authorized users, to authenticate communication participants, preserve the integrity of data, and prevent unauthorized modifications. It has become a common practice to encrypt messages on computer networks, using a variety of encryption tools (algorithms, protocols and applications) in areas such as access controls, protecting banking transactions and e-commerce, or conducting of electronic voting.
The use of encryption procedures in online communication is becoming increasingly important to journalists' work as they need to protect their sources and the obtained data. The encryption application Pretty Good Privacy (PGP) was originally developed to protect email messages, but today it can be used to encrypt other files and mass storage, even to create digital signatures to verify the authenticity of documents. Virtual Private Network (VPN) technology was designed to allow corporate employees to securely connect to their workplace network, but today a variety of VPN providers allows bypassing Internet Service Provider (ISP) servers and hides Internet activities while ensuring the protection of data. On the other hand, VPN can also be used to bypass restrictions on access to the Internet at various organizational levels (in workplaces, states, etc.). For similar purposes, the use of the Tor browser makes it almost impossible to monitor online activities while using a hidden network on the Internet, which allows Internet users to communicate privately and browse websites anonymously.
