Optiga Trust: Generating and Storing Keys in OPTIGA

[tejaChintalapati]

Hi,

I am trying to generate unique key(s) for every device and store them in Optiga to sign the messages, among others. After generating the key pairs, I need the private key stored in Key 2 Data Object(0xE0F1).

Here's my code for generating and storing keys:

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// export private key to host

nrf_crypto_ecc_private_key_t priv_key = {0};

nrf_crypto_ecc_public_key_t pub_key;

priv_key.key_secp256r1.oid = 0xE0F1;

err = nrf_crypto_ecc_key_pair_generate(NULL, &g_nrf_crypto_ecc_secp256r1_curve_info, &priv_key, &pub_key);

DEMO_ERROR_CHECK(err);

XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

  // export private key to host
  nrf_crypto_ecc_private_key_t priv_key = {0};
  nrf_crypto_ecc_public_key_t pub_key;

  priv_key.key_secp256r1.oid = 0xE0F1;
  
  err = nrf_crypto_ecc_key_pair_generate(NULL, &g_nrf_crypto_ecc_secp256r1_curve_info, &priv_key, &pub_key);
  DEMO_ERROR_CHECK(err);

The only difference from the example code is the addition of priv_key.secp256r1.oid = 0xE0F1.

The function, nrf_crypto_ecc_key_pair_generate is fiving me 0xFFFF error, which is a generic OPTIGA_LIB_ERROR. On digging deeper, I found out that CmdLib_GenerateKeyPair is giving 0x80010007 error, which is an: CMD_LIB_INVALID_TAGLEN error.

Can you please tell me what I am missing here?