Data encryption is used for a wide variety of applications in the computer environment. It enables data transmitted via the Internet, such as emails, to be protected through a secure encryption method. With wireless access methods, such as Wifi hotspots, encryption prevents hotspot users from seeing another person's data.
The use of encryption with hard disks and other data storage devices, such as USB sticks or memory cards in smart phones, makes data unusable for unauthorised persons. If a laptop with an encrypted hard disk is stolen, it is impossible for the thief to read any of the data stored on its hard drive without knowing the key. Disk encryption is often used in professional environments where it is necessary to protect critical business data.
However, no encryption method can guarantee absolute security. This is because methods that are currently considered safe can still potentially be vulnerable in the future, due to increasing computing power, new scientific cryptographic findings or by hidden bugs.
In the past, encryption methods have often used symmetrical keys. Both encryption and decryption could be conducted using the same key. The problem with this method is key distribution. If someone comes into possession of the key, they are able to encrypt or decrypt data, as desired, at any time.
Asymmetrical methods use different keys for encryption. Usually, the key pair consists of a public and a private key. Information encrypted with a public key can only be decoded again with the private key. This has the advantage that the private key does not need to be distributed. The public key, however, can be accessible to everyone.
With Voice-over-IP telephony, voice information is in data form, so this can also be encrypted. This protects phone calls from eavesdropping. The usual method in this environment is called the Secure Real-time Transport Protocol (SRTP). Mobile phones utilising FMC (Fixed Mobile Convergence) can also use SRTP for secure calls.