Asymmetric cryptography use cases

STSAFE-A110

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DS13039 Rev 1

2.4

Public key signature verification

The STSAFE-A110 supports signature verification. It can be used to allow an IoT device to

verify the authenticity of a remote server or of the local host firmware used at secure boot or

loaded for firmware update.

Command flow (see Figure 8)

1.

The local host computes a hash over the message.

2.

The local host needs the Public Key that corresponds to the private key that was used

to generate the signature. This key could be stored in the STSAFE-A110 data partition,

so the local host could use the Read command to get it.

3.

The local host needs the ID of the curve used to sign the message.

4.

The local host sends the STSAFE-A110 the Verify Signature[Hash, Signature, Public

Key, Curve ID] command

5.

The STSAFE-A110 verifies the signature and replies with Valid / Invalid.

Figure 8. Public Key Signature Verification command flow

2.5

Applicative data storage

The device comes with 6 Kbytes of EEPROM configurable by the customer for its

application data storage. These 6 Kbytes can be partitioned with the appropriate access

rights.