What is Encryption?
Encryption is a cryptographic technique for ensuring that only authorised parties can access data. In essence, it works by taking source unencrypted data and applying algorithmic obfuscation to it based around an encryption key.
Keys are either symmetric (one key for both encrypt and decrypt) or asymmetric (different keys for encrypt and decrypt), and methods vary widely in their sophistication which tends to define how effective they will be at keeping data secure when under threat.
In the context of the Cloud, encryption is important. When remotely consuming Cloud services it is highly desirable for data to be secure both in flight (between the Cloud datacentre and the device) and at rest (when stored in the Cloud datacentre). In light of this, Cloud service providers take great care in ensuring their platforms make effective use of encryption for communications and storage.