AT88SA100S-SH-T Atmel, AT88SA100S-SH-T Datasheet - Page 4

• Manufacturer Part Number: AT88SA100S-SH-T
• Description: IC BATTERY AUTHENTICATION 8SOIC
• Manufacturer: Atmel
• Series: CryptoAuthentication™r

Specifications of AT88SA100S-SH-T

• Function: Battery Authentication
• Voltage - Supply: 2.7 V ~ 5.25 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (0.154", 3.90mm Width)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

1.4.
1.4.1. SHA Computation Example
4
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:
Digest:
A Read command executed on address zero 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.
Throughout this document, the complete message processed by the SA100S chip is documented. According to
the above specification, this always includes a single bit of ‘1’ pad after the message, followed by a 64-bit value
representing the total number of bits being hashed (less pad and length). If the length is less than 447 (512-64-1)
then the necessary number of ‘0’ bits are included between the ‘1’ pad and ‘length’ to stretch the last message
block out to 512-bits.
When using standard libraries to calculate the SHA-256 digest, these pad and length bits should probably not be
passed to the library as most standard software implementations of the algorithm add them in automatically.
Atmel AT88SA100S
01030507090B0D0F11131517191B1D1F21232527292B2D2F31333537393B3D3F
020406080A0C0E10121416181A1C1E20222426282A2C2E30323436383A3C3E40
08
40 (include serial number in message)
0000
77
8899AABB
CCDD
EEFF
7D38245733717A488575B9F794F7BCAFE033A3848D39430DA25141FDEBEAA1C2
0103…3D3F0204…3E4001400000…EEFF
8558E–SMEM–8/10