When the Internet was invented several decades ago, security was not in the minds of the pioneers. TCP/IP, the protocol used to send data from one point to the next was inherently insecure. Data are being sent over the wire in clear text. Today, advances in encryption technologies enabled the data to be secure while in transit. When you shop at reputable websites, for instance, you can be sure that the credit card number you send over the Internet is encrypted (You will see https on the URL instead of http). Most web applications now (such as gmail, facebook, etc) are encrypted.
However, most of these data, when stored on the servers (data at rest) are still not encrypted. That’s why hackers are still able to get hold of these precious data, such as personally identifiable information (PII) – credit card numbers, social security numbers, etc. as well as trade secrets and other company proprietary information. There are a lot of ways to secure data at rest without encrypting them (such as using better authentication, better physical security, firewalls, using secured applications, better deterrent to social engineering attacks, etc.), but encrypting data at rest is another layer of security to make sure data is not readable when hackers get a hold of them.
The demand for encrypting data at rest is growing, especially now that more data are being moved to the cloud. Enterprise data centers are also being required to encrypt data on their storage systems, either by business or compliance need.
Luckily, IT storage companies such as EMC, NetApp, and many others are now offering encryption for data at rest on their appliances. However, encrypting data is still expensive. Encrypting and decrypting data need a lot of processing power. Moreover, adding encryption to the process may slow down the access of data. Better key management system is also needed. For instance, when using the cloud for storage, data owners (as opposed to service providers) should solely possess the keys and should be able to manage the keys easily.
The Internet will be more secure if data is encrypted not only during transit but also during storage.