Spansion offers the SecSi™ (short for Secured Silicon) Sector on all of its new high density devices to help customers increase system security and lower cost. Systems that charge a fee for access, such as cellular phones and cable systems, are the most likely targets of signal theft. Utilizing an Electronic Serial Number (ESN) permanently locked into the SecSi Sector of Spansion Flash memory devices offers another line of defense against unauthorized access.

The SecSi Sector can help reduce costs, too. Systems that use a discrete ID chip to provide an ESN can utilize the SecSi Sector and eliminate that device! This helps save system board space, and both component and inventory costs. How can you use the SecSi Sector? Read on to find out more about the best protection for your system.

To satisfy customers' needs, the SecSi Sector is available in two standard configurations: Factory Locked and Customer Lockable. The Factory Locked configuration contains a 16 Byte independent, unchangeable, preprogrammed number. Spansion also has the capability to program the subsequent 8 Bytes with a unique, serialized number. The Customer Lockable configuration allows customers to program their own custom numbering scheme or perhaps parametric data into the SecSi Sector. Finally, customers may opt for Spansion to program their custom numbering scheme through our ExpressFlash service. This flexibility enables different customers to utilize the SecSi Sector to meet their different needs.

Factory Locked

Random Number - Cellular Phones
Cellular phones need to be locally programmed with their phone number (unique identifier) and have no need for another unique number. As a result, most cellular phone manufacturers prefer a random numbering scheme. The random number guarantees that there is no pattern for a cloner to predict. This ensures that systems cannot be accessed by extrapolating probable ESNs.

These systems must check that the random number in the SecSi Sector is the same as the recorded number in their system database. Since the system is only performing a check, and not identifying itself using this number, a small number of duplicates are permissible. The random number locked in the SecSi Sector combined with the unique cellular phone number provides effective protection against cloning.

Unique Number Set Top Boxes
Signal piracy accounts for a significant amount of lost revenue for cable and satellite service operators. This piracy drives demand for set top boxes with better security measures. Applications like these benefit by using a secure, unique serial number.

Unique numbering provides every device with a serial number that can be accessed and identified remotely. Because the SecSi sector cannot be modified after it has been locked, a would-be pirate cannot modify the box to emulate one that allows full channel reception. Set top box manufacturers can utilize this number to permanently identify their equipment, control service levels (i.e., which access package a customer is paying for) and record these accesses for billing purposes. Utilizing a unique number in the SecSi Sector provides a simple, effective way to protect against signal theft.

Combination Utilizing both Random and Unique Numbers
By combining the serial and random configurations mentioned above, systems can recognize the benefits of both these numbering schemes. Software algorithms can be designed to address systems using the unique number, then check the random number as an added security measure to ensure that they match. Would-be cloners could not guess what random number was programmed with which unique number.

Customer Lockable
The other standard configuration is Customer Lockable. This configuration allows customers to program the SecSi sector with whatever information they choose. It can contain a proprietary numbering scheme, or some critical system data. This configuration is differentiated from the Factory Locked parts by bit DQ7, which is permanently set to "0" for Customer Lockable parts. The SecSi Sector may only be programmed once, ensuring that no one can change information in the SecSi Sector at a later date when the system is in the field.

Devices with the SecSi Sector feature offer 256 Bytes for programming and ESN and other data requiring extra security. The SecSi Sector of the products may be written to and erased as many times as desired as long as the SecSi Sector hasn't been locked. This capability allows customers to store just a little bit more information than a standard 16 Mb or 32 Mb product would allow. However, once locked, the SecSi Sector will never accept any write or erase commands, and data is permanently protected.