How Encryption for Strong Security Works
File encryption is software whose main task is encryption and decryption of data,
usually in the form of files on hard drives and removable media,
email messages, or in the form of packets sent over computer networks.
Data encryption is the practice and study of hiding information. In modern times,
data encryption is considered a branch of both mathematics and computer science,
and is affiliated closely with information theory, computer security, and engineering.
Link encryption is an approach to communications security
that encrypts and decrypts all traffic at each end of a communications line.
It contrasts with end-to-end encryption where messages are encrypted by the sender
at the point of origin and only decrypted by the intended receiver.
A virtual private network (VPN) is a computer network in which some of the links
between nodes are carried by open connections or virtual circuits
in some larger network instead of by physical wires.
The link-layer protocols of the virtual network are said to be tunneled
through the larger network when this is the case.
One common application is secure communications through the public Internet,
but a VPN need not have explicit security features,
such as authentication or content encryption.