What is System Cryptography?

System cryptography is the practice of using encryption to hide information on a computer. The level of sophistication of such cryptography has increased over time but still varies widely. The phrase system cryptography is used by Microsoft in some editions of Windows for a setting that can set a computer's security levels to meet official standards for government computers.

Early forms of cryptography, long before computers, simply involved replacing individual letters with code letters following a consistent pattern. Other systems involved using code words to replace particular commands or piece of information. These had the advantage that they worked simply and were easy to use if the recipient knew the code system being used, but were difficult to decipher for unauthorized readers.

Such systems, however, are not adequate for computer technology. This is because cracking the encryption system, also known as an algorithm or cipher, is a lengthy process but not a complicated one. For example, if a system replaces each letter with another in the alphabet, it can be solved by simply trying out each possibility until both the system and the encrypted message are found. This would take too long for most humans to bother with, but is a task a computer could carry out very quickly.

Modern system cryptography largely works along similar lines, but use much more complicated algorithms. This greatly increases the time it takes even a computer to crack the algorithm. One problem that remains is that the rapid pace of improvement in computing power and speed means algorithms that once seemed so complex they could never be beaten wind up outdated. Some algorithms have even been cracked by a bank of games consoles.

Perhaps the most significant development in system cryptography is the development of the public and private key systems. Previously, somebody who encrypted information would have to supply the encryption algorithm, or "key," to the intended recipient. If this was intercepted by a hacker along with the information, they would find it much easier to decrypt the data.

The modern system involves the recipient creating the algorithms, not the sender. The recipient creates a public key that says how the data should be encoded, and an associated private key that says how that particular encryption should be decoded. They supply the public key to the sender, who then encrypts the data as requested. At this point, only the recipient is then able to decrypt the data.

Windows XP and its successors include customizable settings for system cryptography. The most notable is "FIPS compliant." This stands for Federal Information Processing Standard, a set of rules that must be followed on computer systems used by federal agencies. The rules require individual encryption algorithms to be approved for use under the standard.