CmdLib_DeriveKey return value

[infineon]

CmdLib_DeriveKey return value

[ozanoner]

@ayushev I appreciate if you can check this issue.

[ayushev]

This is a device error returned from the device, the base for all the device erros is here

https://github.com/Infineon/optiga-trust-x/wiki/Device-Error-Codes

Which parameters are you using for this command, so that the device error is returned? Can you provide a code snippet?

[ozanoner]

It is one of NordicSemi SDK examples. I shared here:
https://gist.github.com/ozanoner/29cdbc72539f0fba39f21dd4fb0e07f0

This function makes a call to optiga_crypt_tls_prf_sha256 at line#43 and in this function, there is a call for CmdLib_DeriveKey. It is the line in which that function returns the value of 0x80010001

optiga-trust-x/optiga/crypt/optiga_crypt.c

Line 449 in 95b37c8

return_value = CmdLib_DeriveKey(&derivekey_options, &derivekey_output_buffer);

[ayushev]

I guess you had a look on this example where the shared secret is written directly to the data object.
There are two nuances

1. It should be 32 bytes non 0x00 bytes long if you use NISTP256 key (by default) -> try using like in example a smaller array of non zero bytes
2. This wiki entry is a short reminder on how to use the function, if you want to see more or less full (and more secure) way to derive a shared secret you can refer to this file

[ozanoner]

Thanks for your reply! I will check those examples.
I double-checked the documentation that you shared above and found that there is a comment for the value of CMD_DEV_ERROR and an example value of 0x80010001.

optiga-trust-x/optiga/include/optiga/cmd/CommandLib.h

Line 50 in 7ae1031

///Device error, the device error(last error code) is available in the least significant byte e.g. for Invalid OID 0x80010001 is returned.

So I got it now how it works :)

Thanks for your time & the help!
Best regards.