Part 2 : Chips for smart cards

1
Part 2 Chips for smart cards

• From Memory chips to Microprocessor and
  Combi-chips

2
The Chip
pad
A Chip
Different memory blocks
Silicon wafer
3
Smart Card Chips

• Silicon Technology for smart card ICs
• Memory chips
• Microprocessor-based Smart Card ICs
• Contactless Memory Card ICs
• Smart CombiCard ICs

At the heart of competition !
4
Silicon Technology

• Custom technology for smart cards
• EEPROM technology (number of write cycles
  10,000 the data retention period 10 years)
• Security sensors (HVI, LVI, Temperature,...
  Sensors detect tampering and destroy the data in
  memory)
• Buried ROM layer or metal shield layer (protect
  against electron microscopy and physical
  tampering)
• Scrambled buses (protect from electron
  microscopes)
• Glued Logic (logical memory mapped onto physical
  one in a random fashion one bit is here, another
  is there, so that without access to the memory
  mapping analysts cannot reconstruct the data)
• Other security modules (current scramblers, ...)
• Low-power (2.2V-5.5V CMOS technology)
• Current chips are using 0.25µ to 0.8µ
  technologies (small feature size)

5
Silicon Technology Evolution

• More Flash / Less ROM for Open OS
• Flash can be written into using the normal card
  communication interface, but it can only be
  erased as a single block.
• More efficient in space and power than EEPROM.
• FERAM (for contactless SC)
• RAM with additional layer which has an effect of
  making it non-volatile.
• Can be used in place of EEPROM, but is more
  efficient (write time nanoseconds requires less
  power).
• Can perform as volatile and non-volatile memory.
• More powerful core (32bit RISC)
• Advanced security features

6
Memory chips

• A non flexible hardware logic

7
Memory chips a fixed physical Mapping

• Example
• Manufacturer issuer area protected by fuses
• Card Secret Code 0 ratification counter
• Access conditions
• Protected area
• 2 User Areas

8
Memory chips a limited command set

• Example 3 commands available (cabled logic)
• READ memory
• UPDATE memory
• Verify Secret Code
• Dedicated communication protocol

9
Microprocessor chips for smart cards

• The state of the art flexible technology

10
Microprocessor architecture
Bus
Co-proc
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Close-up view...
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Different Types of Memory ...

• ROM CPU only NO ACCESS !
• used for embedded Operating System
• PROM Write once, read FOR EVER !
• Used for initialization area (e.g. Lock bytes)
• EEPROM Write, erase, read FLEXIBLE !
• used to store applicative data or added
  functionalities
• RAM Write, erase, read TEMPORARY !
• used during power on sessions only

13
Evolution of memory capacity
Memory trends 2 every 2 years
14
Chip Manufacturing Technology

• Geometry line
• 2001 0.35µ / 0.25µ on EEPROM
• Next 0.18µ versus 0.10µ in other
  technologies.
• Double PolySilicium, One/Double Metal (used for
  inter connection, protection against tampering)
• ROM code diffused (not readable optically)
• Up to 25-30 mask levels on 0.25µ techno
• 1 mask per 1.2 day gt 30-45 days for ROM
  diffusion
• All Products will be 3V5V with very low Power
  Consumption

15
New Non Volatile Memories 1/2

• Flash EEPROM Memory can be written using the
  normal card interface, but can be erased only as
  a block
• Advantages
• Same memory for Program and Data
• Time to Market reduced for prototyping
• Cell size (element to store 1 bit) ratio vs. E²
  1/3 smaller than EEPROM
• Disadvantages
• Granularity Data memory 51232 comparing with
  1-byte access.
• Erase time more important than E² memory
• Cell size larger than ROM (ratio vs. ROM 2/1)

16
New Non Volatile Memories 2/2

• FERAM consists of RAM with additional layer,
  which has an effect of making it non-volatile
  (i.e., retain the data in memory without power)
• Advantages
• Same memory for Program and Data and computing
  area (RAM).
• Same access time for Read, Erase and Write
  (nanoseconds vs. milliseconds in EEPROM)
• Cell size ratio vs. E² 1/3
• Disadvantages
• Technology under development (new technology),
  patented

17
Chip features evolution

• Crypto-processor on board
• higher performance in numerical computations
• e.g. exponentiation as required in PK algorithms
• True Random Number Generator (RNG)
• Memory Access Control matrix
• Enhanced security features
• sensors, protection layers...
• Others (enhanced APIs, embedded algorithms)