2. Tradeoff between security and cost

What kind of challenge is faced by authentication technology?

VuillaumeWhether CPUs are used in authentication technology has an enormous impact on cost. Essentially, unless you are willing to pay the price, security cannot be assured. For example, digital tickets using RFID tags are easy to copy and lack any kind of a security mechanism, but they are very cheap to implement and administer. Turning to DVDs, the content is encrypted so security is fairly robust, but the private key is encoded right along with the content, so the content can be readily counterfeited by simply copying the whole disc. Blu-ray Discs use a copyright protection scheme called BD-ROM Mark that uses a small amount of cryptographic date that is stored separately from the regular disc data, but if you get hold of the unique ID, you can copy a Blu-ray Disc. Secure HDD provides strong security based on digital signatures and encryption, but requires an on-board CPU which drives up the cost.

Figure 3: Authentication technology

Removable memory devices such as memory cards for digital cameras and handheld video game players have become immensely popular and widespread in recent years, so dealing with counterfeit and knockoff memory has suddenly become a huge issue. Of course CPUs supporting digital signatures could be incorporated in memories, but not without significantly adding to the cost of the device. This led us to pursue a different cryptographic approach for supporting authentication in memory devices, an approach that is much more cost effective. We hit upon a cryptographically based authentication scheme that uses low cost memory and a simple memory controller but that does not require a CPU.

Figure 4: Objectives