1. Digital Rights Management
Digital Rights Management, or DRM software mechanisms, provide content owners with the technical ability to prevent the unauthorised use of their content. DRM uses encryption technology to render content inaccessible to those who do not possess the necessary license to view the information.
Apple and many other subscription-based music services do use DRM technology to encrypt music downloaded for offline use. This technology, then, allows them to revoke access to the music if the user cancels his or her subscription to the music service. Similar technologies use encryption to provide digital rights management for other entertainment media such as video games, eBooks, and similar content.
2. Specialised Use Cases
Low Power Use
Some devices operate at extremely low power levels and put a premium on conserving energy. An example is a satellite in space or remote sensors that transmit data using solar power or a very small battery.
Smart cards are another example of a low power environment. They must be able to securely communicate with smart card readers, but only using the energy that’s either stored on the card or transferred to it by a magnetic field. In these cases, cryptographers often design specialised hardware that is purpose-built to implement cryptographic algorithms with as little power use as possible.
Low Latency
Another specialised use case for cryptography are those cases where you need very low latency. That simply means that the encryption and decryption should not take a long time. Encrypting network links is a common example of a requirement for low latency cryptography. Data moves very quickly across a network and the encryption has to be done as quickly as possible to avoid becoming a bottleneck. Specialised encryption hardware solves many low latency requirements.
For example, a dedicated VPN concentrator may contain cryptographic hardware that implements encryption and decryption operations in a highly efficient way to maximise speed and minimise latency.
High Resiliency
High Resiliency requires the protection of encrypted data against loss. High resiliency requirements exist when it is extremely important that data be preserved and not accidentally destroyed during an encryption operation. In cases where resiliency is extremely important, the easiest way to address the issue is for the sender of the data to retain a copy until the recipient confirms the successful receipt and decryption of the data.
