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MicrochipTech / cryptoauthlib

Library for interacting with the Crypto Authentication secure elements
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How do I implement ECDH using cryptoauthlib? #184

Closed ghost closed 3 years ago

ghost commented 3 years ago

I have a Socket server up in Python and the clients are connected using SAME54 (+ ECC608A).

We recognize that there are five tasks to be done with ECDH We are referring to the TLS1.2 handshake.

  1. ECC key exchange
  2. random value exchange
  3. Creating a Pre-Master Secret
  4. Create Master Secret
  5. Key Block Creation

1 the ECC key exchange is done.

xResult = atcab_ecdh_tempkey(&ucPublicKeyDer[ASN1_HEADER_SIZE], &ucPreMasterSecret);

2 can be replaced using the current fixed value. 3 has been created. 4 and 5 have not been created.

In order to create Master Secret and Key Block, which function should I call, and in what order?

bryan-hunt commented 3 years ago

Detailed TLS specification support is really outside the scope of anything we can provide.

bryan-hunt commented 3 years ago

WolfSSL is included in Harmony 3 and comes with a license for use on Microchip Products. Given you're using a SAME54 I would recommend using the onboard ECDH capabilities for ephemeral TLS keys anyway. Regardless WolfSSL has ATECC608A support built in with a tested TLS implementation.

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