topic Re: DESFire Light Symmetric Originality Check in NFC

DESFire Light Symmetric Originality Check

wilmer_suarez — Thu, 17 Dec 2020 19:10:34 GMT

Hello,

I'm working on implementing the necessary LRP algorithms to perform Symmetric Originality Checks on DESFire Light. I'm following the information available in AN12343 and AN12304. I understand the use of an AES key as an input to the precomputation functions is needed. This makes sense when authenticating with any of the internal Application Keys.

However, I don't understand how this works with the Originality Keys. These key are unique to every DESFire Light card, correct?

How do I obtain the Originality Keys?

Are they the same as the Application Keys, as in you can change them?

Re: DESFire Light Symmetric Originality Check

Kan_Li — Tue, 22 Dec 2020 09:50:45 GMT

Hi @wilmer_suarez ,

Please kindly refer to the following for details.

These key are unique to every DESFire Light card, correct?

- Yes, they are.

How do I obtain the Originality Keys?

- This kind of information should be requested from the NXP docstore with a valid NDA, so please contact your local Disty or NXP sales representatives to sign the NDA at first. You may refer to https://www.nxp.com/support/sample-and-buy/distributor-network:DISTRIBUTORS for more details.

Are they the same as the Application Keys, as in yoYpou can change them?

- No, they are not. According to the spec,

• The keys are written on the IC at the production in the NXP factory.
• Keys are created in NXP factory HSM and never leave the secure environment.
• The keys can`t be changed after the IC leaves the NXP factory.

Hope that helps,

Have a great day,
Kan

-------------------------------------------------------------------------------
Note:
- If this post answers your question, please click the "Mark Correct" button. Thank you!
- We are following threads for 7 weeks after the last post, later replies are ignored
Please open a new thread and refer to the closed one, if you have a related question at a later point in time.
-------------------------------------------------------------------------------

Re: DESFire Light Symmetric Originality Check

wilmer_suarez — Tue, 22 Dec 2020 17:48:27 GMT

@Kan_Li Hi, thank you for your response. I currently have a valid NDA on my docstore account. I am unsure where and what to look for in the docstore to find this information. Do I submit a support e-mail?

Re: DESFire Light Symmetric Originality Check

Kan_Li — Tue, 29 Dec 2020 09:01:47 GMT

Hi @wilmer_suarez ,

Yes, please create a private ticket attached with your valid NDA according to the following link.

https://community.nxp.com/t5/Using-Our-Community-Knowledge/How-to-submit-a-new-question-for-NXP-Support/ta-p/1117058

Thanks for your patience!

Have a great day,
Kan