AT88SA10HS-TSU-T Atmel, AT88SA10HS-TSU-T Datasheet - Page 3

• Manufacturer Part Number: AT88SA10HS-TSU-T
• Description: IC HOST AUTHENTICATION SOT23-3
• Manufacturer: Atmel
• Series: CryptoAuthentication™r
• Type: Authentication Chipr

Specifications of AT88SA10HS-TSU-T

• Applications: Networking & Communications
• Mounting Type: Surface Mount
• Package / Case: SOT-23-3
• Operating Supply Voltage: 2.5 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Interface Type: 1 Wire
• Minimum Operating Temperature: - 40 C
• Number Of Timers: 1
• Program Memory Size: 72 bit
• Program Memory Type: ROM
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

1.3.
1.4.
1.5.
8595B–SMEM–09/09
BurnSecure Enable
Secret Fuses
Status Fuses
Fuse Enable
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
Key Values
The values stored in the AT88SA10HS internal key array are hardwired into the masking layers of the chip during wafer
manufacture. All chips have the same keys stored internally, though the value of a particular key cannot be determined
externally from the chip. For this reason, customers should ensure that they program a unique (and secret) number into
the 64 secret fuses and they should store the Atmel provided key values securely.
Individual key values are made available to qualified customers upon request to Atmel and are always transmitted in a
secure manner.
When the serial number is included in the MAC calculation, the response is considered to be diversified and the host
needs to know the base secret in order to be able to verify the authenticity of the client. A diversified response can also
be obtained by including the serial number in the computation of the value written to the secret fuses. The Atmel
AT88SA10HS provides a secure hardware mechanism to validate responses to determine if they are authentic.
SHA-256 Computation
The AT88SA10HS performs only one cryptographic calculation – a keyed digest of an input challenge. It optionally
includes various other information stored on the chip within the digested message.
The AT88SA10HS computes the SHA-256 digest based on the algorithm documented here:
http://csrc.nist.gov/publications/fips/fips180-2/fips180-2.pdf
As a security measure, the 24 bit MfrID code (both ROM and Fuse bits) is automatically included in every message
digested by the AT88SA10HS. The secret fuses are conditionally appended, depending on the parameters to the
HOST command.
For complete sample calculations, refer to”AT88SA100S” and/or “AT88SA102S” Datasheets.
AT88SA10HS Host Authentication Chip [Preliminary]
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.
This fuse is used to prevent repetitive operation of the two personalization commands:
GenPersonalizationKey and BurnSecure. This fuse is always burned by the BurnSecure
command.
These 64 fuses are used to augment the mask programmed keys stored in the chip by
Atmel. Knowledge of both the mask keys and the values of the Secret Fuses is required to
calculate the response value expected by HOST2. The BurnSecure command can be used
to burn an arbitrary selection of these 64 bits.
These 23 fuses should be used to store information which is not secret, as their value can
always be determined using the Read command. Typical usage would be model or
configuration information. They cannot be automatically included in the messages to be
hashed by the HOST commands, but the system may read them and pass them back to
HOST1 in the input stream if desired.
This fuse is used to prevent access to fuses on chips in which a partial set of fuses has
been burned. This fuse must be burned using the BurnSecure command.
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