Unable to Retrieve ECC Curve Details from SE050 using Plug & Trust Nano Package

krsuresh · ‎11-10-2025

Hi Team,

I am currently using the Plug & Trust Nano package to read the ECC curve details from the SE050.
However, I am consistently receiving zero values for the curve details, even though the function call returns a success status.

I have reviewed the APDU configuration and verified my setup based on the following NXP community discussion, but I did not find any issues:
https://community.nxp.com/t5/Secure-Authentication/Read-ECC-Curvelist-fails-when-SCP03-enabled/m-p/1...

Could you please advise on the possible cause of this issue and how I can correctly retrieve the ECC curve details from the SE050?

Environment details:

SE050 variant: SE050-C and SE050-F
Package: Plug & Trust Nano
SCP03 status: Enabled
Host platform: Raspberry Pi

Code Details:

status = Se05x_API_ReadECCurveList(&se05x_session, curveList, &curveListLen);
printf("curveListLen: %d\n", curveListLen);
if (status == SM_OK) {
printf("Supported ECC Curves:\n");
for (i = 0; i < curveListLen; i++) {
printf(" Curve ID: 0x%02X\n", curveList[i]);
}
} else {
printf("Failed to read curve list\n");
}

smStatus_t Se05x_API_ReadECCurveList(pSe05xSession_t session_ctx, uint8_t *data, size_t *pdataLen)
{
smStatus_t retStatus = SM_NOT_OK;
tlvHeader_t hdr = {{kSE05x_CLA, kSE05x_INS_READ, kSE05x_P1_CURVE, kSE05x_P2_LIST}};
size_t cmdbufLen = 0;
uint8_t *pCmdbuf = NULL;
int tlvRet = 0;
uint8_t *pRspbuf = NULL;
size_t rspbufLen = 0;

ENSURE_OR_GO_CLEANUP(session_ctx != NULL);

memset(session_ctx->apdu_buffer, 0, sizeof(session_ctx->apdu_buffer));

pCmdbuf = &session_ctx->apdu_buffer[0];
pRspbuf = &session_ctx->apdu_buffer[0];
rspbufLen = sizeof(session_ctx->apdu_buffer);

SMLOG_D("APDU - Se05x_API_ReadECCurveList [] \n");

retStatus = DoAPDUTxRx(session_ctx, &hdr, session_ctx->apdu_buffer, cmdbufLen, pRspbuf, &rspbufLen, 1);

if (retStatus == SM_OK) {
size_t rspIndex = 0;
tlvRet = tlvGet_u8buf(pRspbuf, &rspIndex, rspbufLen, kSE05x_TAG_1, data, pdataLen); /* */
if (0 != tlvRet) {
goto cleanup;
}
if ((rspIndex + 2) == rspbufLen) {
retStatus = (pRspbuf[rspIndex] << 8 | (pRspbuf[rspIndex + 1]));
}
}
if (retStatus == SM_ERR_ACCESS_DENIED_BASED_ON_POLICY) {
SMLOG_I("Denied to ReadECCurveList");
}

cleanup:
return retStatus;
}

Thanks,

Sureshkumar R

krsuresh · ‎12-01-2025

Hi @Kan_Li,

Thanks for the Information.

I am facing a Bus Error when generating and reading a NIST-P521 public key on the OM-SE050ARD board. However, on the OM-SE050ARD-F board I do not get the Bus Error, but the generated public key appears to be invalid. Any guidance or debugging steps would be appreciated.

Below is the P-521 public key (133 bytes) that triggers the Bus Error:

0x04, 0x00, 0xf0, 0x6f, 0x02, 0x09, 0x86, 0xd8, 0x11, 0x6a, 0x1c, 0x52, 0x2b, 0x25, 0x1f, 0x51,

0x92, 0x94, 0xa5, 0x1a, 0x67, 0x02, 0xe0, 0x4f, 0x45, 0x86, 0x43, 0x9e, 0x6b, 0x17, 0x83, 0x3b,

0xbd, 0xcf, 0x36, 0xaf, 0xa7, 0x35, 0x28, 0xf7, 0x10, 0x02, 0x32, 0x60, 0xdb, 0x72, 0x38, 0xbb,

0x43, 0x32, 0x5c, 0x48, 0x86, 0x32, 0x53, 0x95, 0x6e, 0x4f, 0x18, 0x59, 0xc8, 0xde, 0x81, 0xb4,

0x1b, 0x30, 0xd7, 0x00, 0x16, 0x17, 0x93, 0x83, 0x0a, 0x4c, 0x0d, 0x90, 0x80, 0x2d, 0x1b, 0xf2,

0xfc, 0x75, 0x7d, 0xc2, 0xdb, 0x2f, 0x3a, 0x68, 0xda, 0xbc, 0xce, 0xd5, 0xfd, 0x35, 0x48, 0x15,

0x6c, 0xe8, 0x19, 0xde, 0xef, 0x25, 0x3b, 0x0b, 0xf4, 0xe1, 0x17, 0xad, 0xa2, 0x0d, 0x86, 0xc2,

0x20, 0x61, 0xca, 0x4c, 0x8a, 0x05, 0x5c, 0x0c, 0x5a, 0x16, 0xa6, 0xe5, 0x09, 0x74, 0xc0, 0x9d,

0xc1, 0xd5, 0x37, 0x36, 0xeb,

Bus error

The key from the OM-SE050ARD-F board is:

0x04, 0x00, 0xe5, 0x6a, 0x9c, 0x58, 0x0b, 0xa0, 0x2b, 0x97, 0xf6, 0xc7, 0x05, 0x70, 0x09, 0xb5,

0x12, 0xa6, 0x89, 0x45, 0xf0, 0x28, 0xb5, 0x05, 0xf4, 0x4c, 0x5c, 0x63, 0x7e, 0xf0, 0x7c, 0x2c,

0x79, 0x2a, 0x59, 0x88, 0x7b, 0xa0, 0x8e, 0x38, 0x78, 0x59, 0xc2, 0xa6, 0x9a, 0xe5, 0xa0, 0x47,

0x67, 0xd1, 0xf5, 0x1f, 0x45, 0x55, 0x55, 0x84, 0xfe, 0x33, 0xaa, 0xe0, 0x97, 0xd1, 0xeb, 0x5b,

0xd3, 0x3a, 0x31, 0x01, 0x4e, 0xdb, 0xd2, 0x5a, 0x93, 0xde, 0x3a, 0x86, 0x8b, 0x20, 0xd5, 0xff,

0x2c, 0x96, 0x45, 0x51, 0x55, 0x3f, 0x5b, 0x47, 0x58, 0x5f, 0x42, 0xb9, 0x4d, 0xe1, 0xda, 0x4b,

0xf0, 0x49, 0xb7, 0xc9, 0x8e, 0xf3, 0x12, 0xf1, 0xae, 0x35, 0x02, 0xb9, 0x88, 0x5b, 0x3d, 0x6c,

0x04, 0x91, 0x6f, 0x49, 0xd3, 0x7b, 0xa0, 0xe9, 0x87, 0x09, 0x49, 0xd8, 0x54, 0xd1, 0x5f, 0xae,

0xa8, 0x54, 0xac, 0x88, 0x02,

Code details:

/* secp521r1 : NIST/SECG curve over a 521 bit prime field */

#define EC_PARAM_secp521r1_prime \

0x01, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, \

0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, \

0xFF, 0xFF

#define EC_PARAM_secp521r1_a \

0x01, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, \

0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, \

0xFF, 0xFC

#define EC_PARAM_secp521r1_b \

0x00, 0x51, 0x95, 0x3E, 0xB9, 0x61, 0x8E, 0x1C, \

0x9A, 0x1F, 0x92, 0x9A, 0x21, 0xA0, 0xB6, 0x85, \

0x40, 0xEE, 0xA2, 0xDA, 0x72, 0x5B, 0x99, 0xB3, \

0x15, 0xF3, 0xB8, 0xB4, 0x89, 0x91, 0x8E, 0xF1, \

0x09, 0xE1, 0x56, 0x19, 0x39, 0x51, 0xEC, 0x7E, \

0x93, 0x7B, 0x16, 0x52, 0xC0, 0xBD, 0x3B, 0xB1, \

0xBF, 0x07, 0x35, 0x73, 0xDF, 0x88, 0x3D, 0x2C, \

0x34, 0xF1, 0xEF, 0x45, 0x1F, 0xD4, 0x6B, 0x50, \

0x3F, 0x00

#define EC_PARAM_secp521r1_x \

0x00, 0xC6, 0x85, 0x8E, 0x06, 0xB7, 0x04, 0x04, \

0xE9, 0xCD, 0x9E, 0x3E, 0xCB, 0x66, 0x23, 0x95, \

0xB4, 0x42, 0x9C, 0x64, 0x81, 0x39, 0x05, 0x3F, \

0xB5, 0x21, 0xF8, 0x28, 0xAF, 0x60, 0x6B, 0x4D, \

0x3D, 0xBA, 0xA1, 0x4B, 0x5E, 0x77, 0xEF, 0xE7, \

0x59, 0x28, 0xFE, 0x1D, 0xC1, 0x27, 0xA2, 0xFF, \

0xA8, 0xDE, 0x33, 0x48, 0xB3, 0xC1, 0x85, 0x6A, \

0x42, 0x9B, 0xF9, 0x7E, 0x7E, 0x31, 0xC2, 0xE5, \

0xBD, 0x66

#define EC_PARAM_secp521r1_y \

0x01, 0x18, 0x39, 0x29, 0x6A, 0x78, 0x9A, 0x3B, \

0xC0, 0x04, 0x5C, 0x8A, 0x5F, 0xB4, 0x2C, 0x7D, \

0x1B, 0xD9, 0x98, 0xF5, 0x44, 0x49, 0x57, 0x9B, \

0x44, 0x68, 0x17, 0xAF, 0xBD, 0x17, 0x27, 0x3E, \

0x66, 0x2C, 0x97, 0xEE, 0x72, 0x99, 0x5E, 0xF4, \

0x26, 0x40, 0xC5, 0x50, 0xB9, 0x01, 0x3F, 0xAD, \

0x07, 0x61, 0x35, 0x3C, 0x70, 0x86, 0xA2, 0x72, \

0xC2, 0x40, 0x88, 0xBE, 0x94, 0x76, 0x9F, 0xD1, \

0x66, 0x50

#define EC_PARAM_secp521r1_order \

0x01, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, \

0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, \

0xFF, 0xFA, 0x51, 0x86, 0x87, 0x83, 0xBF, 0x2F, \

0x96, 0x6B, 0x7F, 0xCC, 0x01, 0x48, 0xF7, 0x09, \

0xA5, 0xD0, 0x3B, 0xB5, 0xC9, 0xB8, 0x89, 0x9C, \

0x47, 0xAE, 0xBB, 0x6F, 0xB7, 0x1E, 0x91, 0x38, \

0x64, 0x09

curveID = kSE05x_ECCurve_NIST_P521;

status = Se05x_API_ReadECCurveList(&se05x_session, curveList, &curveListLen);

if (status != SM_OK) {

SMLOG_E("Error in Se05x_API_ReadECCurveList \n");

}

else {

if (curveList[curveID - 1] == kSE05x_SetIndicator_SET) {

SMLOG_I("curveID = %0x already exists \n", curveID);

}

else {

status = ex_se05x_create_curve_p521(&se05x_session, curveID);

if (status != SM_OK) {

SMLOG_I("Error in ex_se05x_create_curve \n");

}

status = Se05x_API_CheckObjectExists(&se05x_session, keyID, &result);

if (status != SM_OK) {

SMLOG_E("[SE050] Error in Se05x_API_CheckObjectExists \n");

return SE050_FAILURE;

}

if (result == kSE05x_Result_SUCCESS) {

curveID = kSE05x_ECCurve_NA;

}

status = Se05x_API_WriteECKey(

&se05x_session, NULL, 0, keyID, curveID, NULL, 0, NULL, 0, kSE05x_INS_NA, kSE05x_KeyPart_Pair);

if (status != SM_OK) {

SMLOG_E("[SE050] Error in Se05x_API_WriteECKey \n");

Se05x_Delete_Session(keyID);

return SE050_FAILURE;

}

uint8_t key_buf[256] = {

0,

};

size_t key_buflen = sizeof(key_buf);

status = Se05x_API_ReadObject(&se05x_session, keyID, 0, 0, key_buf, &key_buflen);

if (status != SM_OK) {

SMLOG_E("Error in Se05x_API_ReadObject \n");

return SE050_FAILURE;

}

Thanks,

Sureshkumar R