Hi. I'm using nRF52832, SDK13.0.0.
I want to use CURVE25519.
I made my code refering to example "ble_app_multirole_lesc" and "nrf_crypto_keys.h".
NRF_CRYPTO_ECC_PRIVATE_KEY_CREATE(alice_private_key, SECP256R1);
NRF_CRYPTO_ECC_PRIVATE_KEY_CREATE(bob_private_key, SECP256R1);
NRF_CRYPTO_ECC_PUBLIC_KEY_CREATE(alice_public_key, SECP256R1);
NRF_CRYPTO_ECC_PUBLIC_KEY_CREATE(bob_public_key, SECP256R1);
static void alice_step_1()
{
SEGGER_RTT_printf_log(0, "%s\n", __func__);
uint32_t ret_val;
ret_val = nrf_crypto_ecc_key_pair_generate(NRF_CRYPTO_BLE_ECDH_CURVE_INFO, &alice_private_key, &alice_public_key);
APP_ERROR_CHECK(ret_val);
SEGGER_RTT_printf_log_Hex(0, "alice_private_key :", alice_private_key.p_value, alice_private_key.length);
SEGGER_RTT_printf_log_Hex(0, "alice_public_key :", alice_public_key.p_value, alice_public_key.length);
}
static void alice_step_2()
{
SEGGER_RTT_printf_log(0, "%s\n", __func__);
ret_code_t err_code = NRF_SUCCESS;
err_code = nrf_crypto_ecdh_shared_secret_compute(NRF_CRYPTO_BLE_ECDH_CURVE_INFO,
&alice_private_key,
&bob_public_key,
&m_dh_key);
APP_ERROR_CHECK(err_code);
SEGGER_RTT_printf_log_Hex(0, "alice's m_dh_key :", m_dh_key.p_value, m_dh_key.length);
}
void bob_step_1()
{
SEGGER_RTT_printf_log(0, "%s\n", __func__);
uint32_t ret_val;
ret_val = nrf_crypto_ecc_key_pair_generate(NRF_CRYPTO_BLE_ECDH_CURVE_INFO, &bob_private_key, &bob_public_key);
APP_ERROR_CHECK(ret_val);
SEGGER_RTT_printf_log_Hex(0, "bob_private_key : ", bob_private_key.p_value, bob_private_key.length);
SEGGER_RTT_printf_log_Hex(0, "bob_public_key : ", bob_public_key.p_value, bob_public_key.length);
}
void bob_step_2()
{
SEGGER_RTT_printf_log(0, "%s\n", __func__);
ret_code_t err_code = NRF_SUCCESS;
err_code = nrf_crypto_ecdh_shared_secret_compute(NRF_CRYPTO_BLE_ECDH_CURVE_INFO,
&bob_private_key,
&alice_public_key,
&m_dh_key);
APP_ERROR_CHECK(err_code);
SEGGER_RTT_printf_log_Hex(0, "bob's m_dh_key :", m_dh_key.p_value, m_dh_key.length);
}
unsigned int secure_test(void)
{
alice_step_1(); // Alice sends her public key to Bob
bob_step_1(); // Bob generates new key pair and sends his public key to Alice
alice_step_2(); // Alice receives Bob's public key and computes shared secret
bob_step_2(); // Bob receives Alice's public key and computes shared secret
return 0;
}
I can see it works very well. Alice's m_dh_key and Bob's m_dh_key are same.
My goal is "using CURVE25519"
So I modified my code and "nrf_crypto_keys.h".
#define NRF_CRYPTO_BLE_ECDH_CURVE_INFO (nrf_crypto_curve_info_t) \
{ \
.curve_type = NRF_CRYPTO_CURVE_CURVE25519, \
.endian_type = NRF_CRYPTO_ENDIAN_LE \
}
NRF_CRYPTO_ECC_PRIVATE_KEY_CREATE(alice_private_key, CURVE25519);
NRF_CRYPTO_ECC_PRIVATE_KEY_CREATE(bob_private_key, CURVE25519);
NRF_CRYPTO_ECC_PUBLIC_KEY_CREATE(alice_public_key, CURVE25519);
NRF_CRYPTO_ECC_PUBLIC_KEY_CREATE(bob_public_key, CURVE25519);
But it makes error a lot.
The information in "nrf_crypto_keys.h" says as below.
* @param[in] type Curve type. Either SECP192R1, SECP224R1, SECP256R1, SECP384R1,
* SECP521R1, SECP192K1, SECP224K1, or SECP256K1.
There is no information for CURVE25519.
How can I use CURVE25519?
I need your help.
