January 17, 2007
FlexiHash™ For Battery Authentication
The ISL6296 is a highly cost-effective fixed-secret hash
engine based on Intersil’s FlexiHash™ technology. The
device authentication is achieved through a challenge-
response scheme customized for low-cost applications,
where cloning via eavesdropping without knowledge of the
device’s secret code is not economically viable. When used
for its intended applications, the ISL6296 offers the same
level of effectiveness as other significantly more expensive
high maintenance monetary-grade hash algorithm and
The ISL6296 has a wide operating voltage range, and is
suitable for direct powering from a 1-cell Li-Ion/Li-Poly or a
3-cell series NiMH battery pack. The ISL6296 can also be
powered by the XSD bus when the bus pull-up voltage is
3.3V or higher. The device connects directly to the cell
terminals of a battery pack, and includes on-chip voltage
regulation circuit, POR, and a non-crystal based oscillator for
bus timing reference.
Communication with the host is achieved through a single-
wire XSD interface - a light-weight subset of Intersil’s ISD bus
interface. The XSD bus is compatible for use with serial ports
offered by all 8250 compatible UART’s or a single GPIO
(general purpose input and output) pin of a microprocessor.
A clone prevention solution utilizing the ISL6296 offers
safety and revenue protection at the lowest cost and power,
and is suitable for protection against after-market
replacement for a wide variety of low-cost applications.
(5 LD SOT-23)
(8 LD 2X3TDFN)
• Challenge-response based authentication scheme using
32-Bit challenge code and 8-Bit authentication code.
• Fast and flexible authentication process. Multi-pass
authentication can be used to achieve the highest security
level if necessary.
• 16x8 OTP ROM stores up to three sets of 32-Bit host-
selectable secrets with additional programmable memory
for storage of up to 48 bits of ID code and/or pack
• FlexiHash engine uses two sets of 32-Bit secrets for
authentication code generation.
• Non-unique mapping of the secret key to an 8-Bit
authentication code maximizes hacking difficulty due to
need for exhaustive key search (superior to SHA-1).
• Supports 1-cell Li-Ion/Li-Poly and 3-cell series NiMH
battery packs (2.6V ~ 4.8V operation), or powered by the
• XSD single-wire host bus interface communicates with all
8250-compatible UART’s or a single GPIO. Supports CRC
on read data and transfer bit-rate up to 23kbps.
• True “Zero Power” Sleep mode - automatically entered
after a bus inactivity time-out period
• 5 Ld SOT-23 and 8 Ld TDFN (2mm x 3mm) packages
• -20°C to +85°C operating temperature range
• Pb-free plus anneal available (RoHS compliant)
• Battery Pack Authentication
• Printer Cartridges
• Add-on Accessories
• Other Non-Monetary Authentication Applications
• Application Note AN1165 “ISL6296 Evaluation Kit”
• Application Note AN1166 “FlexiHash™ Engine Algorithm”
• Application Note AN1167 “Implementing XSD Host Using
• Technical Brief TB363 “Guidelines for Handling and
Processing Moisture Sensitive Surface Mount Devices
1 CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 1-888-468-3774 | Intersil (and design) is a registered trademark of Intersil Americas Inc.
Copyright © Intersil Americas Inc. 2005, 2006, 2007. All Rights Reserved.
FlexiHash is a trademark of Intersil Americas Inc. All other trademarks mentioned are the property of their respective owners.