ATSHA204 ATMEL [ATMEL Corporation], ATSHA204 Datasheet - Page 2

• Manufacturer Part Number: ATSHA204
• Description: Atmel CryptoAuthentication
• Manufacturer: ATMEL [ATMEL Corporation]

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Introduction
The following sections introduce the features and functions of the Atmel
Applications
The ATSHA204 is a member of the Atmel CryptoAuthentication™ family of high-security hardware authentication devices. It
has a flexible command set that allows use for many applications, including the following:
Device Features
The ATSHA204 includes an Electrically Erasable Programmable Read-only Memory (EEPROM) array that can be used for
storage of keys, miscellaneous read/write, read-only or secret data, consumption logging, and security configuration. Access
to the various sections of memory can be restricted in a variety of ways and the configuration then locked to prevent changes.
See Section 2.1, “EEPROM Organization,” for more details on the EEPROM organization.
The ATSHA204 features a wide array of defensive mechanisms specifically designed to prevent physical attacks on the device
itself or logical attacks on the data transmitted between the device and the system (See Section 3.4, “Security Features,” for
more details). Hardware restrictions on the ways in which keys are used or generated, described in Section 3.3, “Key Values,”
provide further defense against certain styles of attack.
Access to the device is through a standard I
It is compatible with standard serial EEPROM I
can reduce the number of GPIOs required on the system processor and/or reduce the number of pins on connectors. The
single-wire interface is described in more detail in Section 5, “Single-wire Interface.”
Using either the I
GPIO usage in systems with multiple clients such as different color ink tanks or multiple spare parts. See Section 4.2, “Sharing
the Interface,” and Section 8.10, “Pause Command,” for more details on the way in which this is implemented.
Each ATSHA204 ships with a guaranteed unique 72-bit serial number. Using the cryptographic protocols supported by the
device, a host system or remote server can prove that the serial number is both authentic and not a copy. Serial numbers are
often stored in a standard serial EEPROM, but these can be easily copied, and there is no way for the host to know if the serial
number is authentic or a clone.
The Atmel ATSHA204 can generate high-quality random numbers and employ them for any purpose, including as part of the
crypto protocols of this device. Because each 256-bit random number is guaranteed to be unique from all numbers ever
generated on this or any other device, their inclusion in the protocol calculation ensures that replay attacks (re-transmitting a
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Anti-counterfeiting
Protection for Firmware or Media
Session Key Exchange
Secure Data Storage
User Password Checking
Validate that a removable, replaceable, or consumable client is authentic. Example clients could be printer ink tanks,
electronic daughter cards, or other spare parts. It can also be used to validate a software/firmware module or
memory storage element.
Validate code stored in flash memory at boot to prevent unauthorized modifications (aka secure boot), encrypt
downloaded media files, and uniquely encrypt code images to be usable on a single system only.
Securely and easily exchange stream encryption keys for use by an encryption/decryption engine in the system
microprocessor to manage such things as a confidential communications channel or an encrypted download.
Store secret keys for use by crypto accelerators in standard microprocessors. It can also be used to store small
quantities of data necessary for configuration, calibration, ePurse value, consumption data, or other secrets.
Programmable protection up through encrypted/authenticated reads and writes.
Validate user entered passwords without letting the expected value become known, map simple passwords to
complex ones, and securely exchange password values with remote system.
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C or single-wire interface, multiple ATSHA204 devices can share the same bus, which saves processor
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C interface at speeds up to 1Mbit/sec (See Section 6 for details on this interface).
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C interface specifications. The device also supports a single-wire interface that
®
ATSHA204 authentication device.
Atmel ATSHA204 [DATASHEET]
8740D−CRYPTO−3/12
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