at88sa100s ATMEL Corporation, at88sa100s Datasheet - Page 3

• Manufacturer Part Number: at88sa100s
• Description: Battery Authentication Chip
• Manufacturer: ATMEL Corporation

1.3.
1.4.
1.4.1. SHA Computation Example
8558B–SMEM–09/09
Chip Identification
The chip includes a total of 72 bits of information that can be used to distinguish between individual chips in a reliable
manner. The information is distributed between the ROM and fuse blocks in the following manner.
Serial Number
Manufacturing ID This 24 bit value is composed of ROM MfrID (16 bits) and Fuse MfrID (8 bits). Typically this value
SHA-256 Computation
This chip performs only one cryptographic calculation – a keyed digest of an input challenge using the SHA-256
algorithm, documented here:
http://csrc.nist.gov/publications/fips/fips180-2/fips180-2.pdf
In order to ensure that there is no ambiguity, the following example vector is provided in addition to the sample vectors
in the NIST document. In this example, all values are listed in hex. For all but the key, bytes are listed in the order that
they appear on the bus – first on the left. Key is listed in the same order, so the 01 at the left of the key string is the first
byte passed to SHA-256.
Key
Challenge
Opcode
Mode
Param2
Fuse MfrID
Fuse S/N
ROM MfrID
ROM SN
The 88 bytes over which the digest is calculated are 0103…3D3F0204…3E4001400000…EEFF
Digest:
A Read command executed on address 0 of the ROM (ROM MfrID, ROM SN) would return CC DD EE FF, with CC
being the first byte on the bus and FF being the last.
1.
2.
01030507090B0D0F11131517191B1D1F21232527292B2D2F31333537393B3D3F
020406080A0C0E10121416181A1C1E20222426282A2C2E30323436383A3C3E40
01
40
0000
77
8899AABB
CCDD
EEFF
7D38245733717A488575B9F794F7BCAFE033A3848D39430DA25141FDEBEAA1C2
This 48 bit value is composed of ROM SN (16 bits) and Fuse SN (32 bits). Together they form a
serial number that is guaranteed to be unique for all devices ever manufactured within the
CryptoAuthentication family. This value is optionally included in the MAC calculation.
is the same for all chips of a given type. It is always included in the cryptographic computations.
Consumption logging, i.e. burn one bit after every n uses, the host system keeps track of the
number of uses so far for this serial number since the last fuse burn.
Model number information. In this situation, the bits are written at the factory and their value is
locked to prevent modifications in the field. This method can also be used for feature enabling.
(include serial number in message)
AT88SA100S [ Preliminary]
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