STSAFE-A110 datasheet(20/36 Pages) STMICROELECTRONICS

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Pairing with a local host

STSAFE-A110

20/36

DS13039 Rev 1

Command flow (see Figure 12)

Generation of the local envelope Key

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The local host queries the STSAFE-A110 to randomly generate a local envelope

key in one of the two slots, using the GENERATE KEY command.

Wrapping of local envelope

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The local host builds the local envelope by using the STSAFE-A110’s Wrap local

envelop command

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This command requires a local host’s C-MAC, plain text data (usually a

cryptographic key that needs to be encrypted with the host’s cipher key) and the

local envelope key slot number (the key to use for encryption of plain text data).

–

The response to the Wrap Local envelope command contains the envelope (plain

text is encrypted using the Local envelope key).

Unwrapping of local envelope by receiver

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The local host provides the local envelope to the STSAFE-A110 by using the

Unwrap local envelop command and the local envelope key slot.

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The host must generate a local host’s C-MAC with the command.

–

The STSAFE-A110 provides the envelope cryptogram (usually a cryptographic

key) decrypted with the local envelope key) in its response.

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The response is encrypted using the host’s cipher key.

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The host decrypts the response with the host’s cipher key and obtains the

decrypted envelope cryptogram.

STSAFE-A110 Datasheet(PDF) 20 Page - STMicroelectronics