Hi @williams 
As suggested by you creating this request in the emailing list

I just want to create a "AES key" using TPM , i could find the below sample of RSA key generation using tpm2tss_rsa_genkey() API . Could you help me on sharing the API or sample code block that helps me to generate "AES based key" using TPM ?

rsa = RSA_new();
if (!rsa) {
ERR("out of memory\n");
BN_free(e);
return NULL;
}
if (!tpm2tss_rsa_genkey(rsa, opt.keysize, e, opt.password, opt.parent)) {
BN_free(e);
RSA_free(rsa);
ERR("Error: Generating key failed\n");
return NULL;
}

You have suggested to use - Esys_Create, with the public template filled in for an AES key.
I have found the sample of the same in https://github.com/tpm2-software/tpm2-tss/blob/master/test/integration/esys-encrypt-decrypt.int.c

And the below code block/structure that enable "AES" based key generation was  shared below. Can you please confirm whether am i going in correct direction to achieve my requirement . It would be great if you have any sample code to be shared with me on this front.
...
..
 TPM2B_PUBLIC inPublic2 = {
..
..
.parameters.rsaDetail = {
                 .symmetric = {
                     .algorithm = TPM2_ALG_AES,
                     .keyBits.aes = 128,
                     .mode.aes = TPM2_ALG_CFB},
                 .scheme = {
                      .scheme = TPM2_ALG_NULL
                  },
                 .keyBits = 2048,
                 .exponent = 0,
             },

...
...
}

/* Esys_Create API , which will take above struct inputs filled by user as 
  r = Esys_Create(esys_context,
                    primaryHandle,
                    ESYS_TR_PASSWORD, ESYS_TR_NONE, ESYS_TR_NONE,
                    &inSensitive2,
                    &inPublic2,    /* in this struct we are filling that we required AES based input key gen */
                    &outsideInfo2,
                    &creationPCR2,
                    &outPrivate2,
                    &outPublic2,
                    &creationData2, &creationHash2, &creationTicket2);
                           &creationTicket);