Desfire with ISO 7816 and AES keys

[Stefan Winter]

After I select a file on the Desfire with the "A4" command, I want to authenticate for reading data. The card has only AES keys. How can I tell the Get-Challenge "84" which key to use for encryption of the challenge ? Using the external authentication after requesting a 16 bytes challenge and generating a 16 bytes RND-A results always in an length error 67 00. Maybe it's not possible to authenticate with AES keys in ISO 7816 ?

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[Stefan Winter]

Found the solution myself. Have to set the P1 and P2 according to the desired algorithm.

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[Woman Tops]

It seems like you're facing an issue with the "A4" command on Desfire after selecting a file. To authenticate for reading data with AES keys, you may need to specify the key for encryption when using the Get-Challenge "84" command. However, using external authentication with a 16-byte challenge and generating a 16-byte RND-A results in a length error 67 00. You're wondering if it's possible to authenticate with AES keys in ISO 7816. Any insights on resolving this issue would be appreciated.

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[Edward Booth]

Thank you!

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