topic Using Easy-Ecc to Verify Originality Signature for NTAG213 in NFC

Using Easy-Ecc to Verify Originality Signature for NTAG213

andreas3 — Wed, 05 Aug 2020 14:48:34 GMT

Hi,
I am referring to

AN11350 NTAG Originality Signature Validation

and the described example to verify an NXP originality signature with lib Easy-Ecc, Chapter 2.2.1.3 C code example.
I am using a NTAG213 and want to verify the originality signature.

If I exactly do what is described in this chapter, using the pubKey, UID and Sig, the function ecdsa_verify() reports an invalid signature.
What makes me a bit surprised is that the function ecdsa_verify() expects a key input of size: ECC_BYTES+1, which is 17 in case of the proposed curve secp128r1. The given NXP public key has a length of 33 instead.
So, does anyone got this going with a successful verification???

To clarify, I am using the pubKey, UID and SIg provided by the application note example for a first test.

Thanks and best regards

Andreas

Re: Using Easy-Ecc to Verify Originality Signature for NTAG213

Kan_Li — Thu, 27 Aug 2020 05:59:25 GMT

Hello Andreas,

Actually Easy-Ecc lib can be used to verify an NXP originality signature as described in AN11350, but some slight modification is needed as well. Due to this information is confidential, please kindly create a private ticket for it. You may refer to How to submit a new question for NXP Support for details.

Thanks for your patience and understanding!

Have a great day,
Kan

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