What do you need to establish computer security?

Created May 3, 2012

Lennart Jorelid

There are essentially four aspects of computer security:

Aspect	Generally achieved by	Explanation	Effect
Confidentiality	Encryption	Protects message content from any but sender and recipient	Transmission eavesdroppers cannot read or use the message content.
Integrity	Message Digest	Verifies that a message has not been modified since it was sent	Transmission hijackers cannot modify message in transit
Authenticity	Digital Signature + Password	Uniquely identifies the sender of a message	Verification of actual sender possible
Nonrepudiation	Cryptographic Receipt	Prevents a sender from falsely denying sending a message	Message recipient can prove that a message was sent by sender

The first two aspects restrict unwanted interception or modification of a message in transit between a sender and a recipient. The last two aspects ensures that the identity of the sender can be pinpointed.