General Description
The DS28E25 combines crypto-strong, bidirectional, secure challenge-and-response authentication functionality with an implementation based on the FIPS 180-3-specified Secure Hash Algorithm (SHA-256). A 4Kb user-programmable EEPROM array provides nonvolatile storage of application data and additional protected memory holds a read-protected secret for SHA- 256 operations and settings for user memory control.

FEATUREs
♦ Symmetric Key-Based Bidirectional Secure Authentication Model Based on SHA-256
♦ Dedicated Hardware-Accelerated SHA Engine for Generating SHA-256 MACs
♦ Strong Authentication with a High Bit Count, UserProgrammable Secret, and Input Challenge
♦ 4096 Bits of User EEPROM Partitioned Into 16 Pages of 256 Bits
♦ User-Programmable and Irreversible EEPROM Protection Modes Including Authentication, Write and Read Protect, and OTP/EPROM Emulation
♦ Unique, Factory-Programmed 64-Bit Identification Number
♦ Single-Contact 1-Wire Interface Communicates with Host at Up to 76.9kbps
♦ Operating Range: 3.3V ±10%, -40NC to +85NC
♦ Low-Power 5µA (typ) Standby
♦ ±8kV Human Body Model ESD Protection (typ)
♦ 2-Pin SFN, 6-Pin TDFN, 6-Lead TSOC Packages

APPLICATIONs
    Authentication of Network-Attached Appliances
    Printer Cartridge ID/Authentication
    Reference Design License Management
    System Intellectual Property Protection
    Sensor/Accessory Authentication and Calibration
    Secure Feature Setting for Configurable Systems
    Key Generation and Exchange for Cryptographic Systems