Creativity in Silicon



Micro-Sized, Ultra-Low Cost USB Software Authentication Key

TEAleaf-USB is an ultra-low cost, micro-sized authentication system for verifying that a software product is authorized and not a pirate copy. It uses a simple but robust xTEA algorithm to verify that a TEAleaf-USB device is present.

TEAleaf-USB uses the Human Interface Device (HID) USB profile. It does not require USB drivers and is immediately plug-and-play compatible with present and future Windows, Linux and Mac operating systems.

TEAleaf-USB is marketed by FlexiPanel as complete, finished product.  It is also as an integrated circuit and design blueprint for customers with electronics manufacturing capacity. (See


  • Computer software copy protection and licensing

  • Pay-per-use hardware protection

  • True random number generation


  • True USB 2.0 HID plug and play - No drivers required

  • Ultra low cost integrated connector

  • Security key, product name, manufacturer name, GUID configurable from USB interface

  • 122-byte EEPROM


Authentication requires the PC and the TEAleaf-USB to generate random numbers and then test that they both know how to encrypt and decrypt them. First the PC needs to prove to the TEAleaf that it knows the 128-bit key, then the TEAleaf-USB proves it knows it too. Bits are masked from each proof to ensure that decryption attacks are fruitless.

A true random number generator provides the required robustness against hacking. It detects marginal differences in temperature, operating voltage, device chemistry, age and quantum effects to derive a unpredictable value. 192 random bits are generated during startup. These are then fed into a high-avalanche polynomial ring to derive a 192-bit random number.

Data Sheet

Development Kit