By Artur Costa
PLANETA INFORMATICA LTDA /Brasil
The Challenge
Two years ago, a customer hired Planeta to improve
an existing highly secure purse application with a
big restriction: user card cost. The customer already
had a pilot application in place, based on two
microprocessors: one for the user card and another
used inside a terminal that worked as a secure
authentication module (SAM). Planeta was asked to
suggest a new smart card concept with the same
level of security and a lower price for the user card.
In addition, the current system was limited to a
single smart card manufacturer and had some
performance issues that needed to be resolved.
The Solution
Planeta had previously used Atmel’s AT88SC153
chip, a predecessor of the new CryptoMemory®
family of devices. The AT88SC153 was
successfully implemented in a vending machine
application, with the application and card secret
keys saved and protected inside the terminal’s
protected memory. Since the security of “protected
terminal memory” is not reliable enough, the
solution for the secure purse application required a
new concept of secret keys, diversification of keys,
and secure calculations performed by a SAM card
instead of a CPU terminal.
While Planeta was working on this solution, Atmel
launched the CryptoMemory family of chips, offering
very high security functionalities, like bidirectional
authentication, encrypted passwords, physical/
electrical monitors, and encrypted and signed
communication between card and reader/terminal.
Because of these features, Planeta selected
CryptoMemory for the user card platform.
The next step was to find the SAM platform.
We needed a versatile solution that could be used
for different applications like access control,
public transportation, vending machines, and
multi-application cards. Atmel’s CryptoMemory and
CryptoRF™ families of devices met these needs.
Design Strategy
The answer was to adopt a fully programmable,
high-performance, secure processor card for the
SAM. Planeta selected Atmel’s AT90SC6464C,
a flash-based, high-performance cryptocontroller.
The key elements of this new solution included:
• CryptoMemory AT88SC0808C for the user card.
• AVR™ secure Flash microcontroller AT90SC6464C
for the SAM card.
The SAM was built using Atmel’s very high-
performance microcontroller, which has a built-in
random number generator, 3DES/RSA hardware
accelerator, and ISO 7816 interface. To work with the
SAM, the External Memory Operating System
(EMOS) was selected, because it has the unique
ability to utilize the memory in external smart cards
as if they were part of the microcontroller memory.
In addition, the external smart card memory needed
to have mutual authentication and encrypted
communication ability to ensure the security of the
system. Since CryptoMemory is the only chip in the
marketplace with authentication and encryption
functions, CryptoMemory provided the solution for
the secure purse application.
The end result is that the solution developed by
Planeta provides the same functionality as a pair of
microprocessor cards (user and SAM cards),
meeting the customer’s requirements quickly and at
a low cost.
The Advantages
• Cost reduction: The CryptoMemory user card is
about one-third the cost of a microprocessor card
with the same memory size.
• Very high security.
• Total independence of card manufacturer
and personalization.
• Very high performance: The AT90SC6464C chip
has a very fast encryption calculation engine.
• Simplified memory management: The SAM
manages system memory, building necessary
application files within the CryptoMemory and
CryptoRF user memory and SAM memory.
• Flexibility: This solution can use a wide range of
memory sizes for contact (up to 32K bytes) and
contactless smart cards (up to 8K bytes), with the
same level of security and interface as micro-
processor cards.
PLANETA INFORMATICA IS A
DESIGN AND MANUFACTURING
COMPANY, SPECIALIZING IN
CONTACT AND CONTACTLESS
SMART CARD READERS, TERMINALS,
AND BOARDS FOR DEDICATED
APPLICATIONS, INCLUDING PUBLIC
TRANSPORTATION, VENDING
MACHINES, FOOD VOUCHERS,
LOTTERY, AND GAMING. FOR THE
LAST 10 YEARS, PLANETA HAS
DEVELOPED AND PROVIDED
CUSTOMERS WITH SECURE,
INEXPENSIVE SMART
CARD-BASED SOLUTIONS.
www.atmel.com
page 50
SAM-Based Highly Secure Application using
Atmel CryptoMemory
®
and CryptoRF
™
Devices
J O U R N A L
A T M E L
A P P L I C A T I O N S
