get ecc public key from x and y components in PEM format using openssl - encryption

Question

Can I get the ecc public key from x and y components in PEM format using openssl?
X:
1d 43 15 e3 84 99 d6 f6 9f 49 61 8a ae ec f2 4f
Y:
b5 1a 86 cf f9 0e 01 af 3a 9a 52 b3 c6 58 2c 48
thank you!!!!!!!!!!!

Answer 1

Yes it is possible. Here an example in C.
int main(void)
{
EC_GROUP *group;
EC_POINT *point;
EC_KEY *key;
BIGNUM *x, *y;
BIO *out;
ERR_load_crypto_strings();
OpenSSL_add_all_algorithms();
group = EC_GROUP_new_by_curve_name(NID_secp256k1);
x = BN_new();
y = BN_new();
BN_hex2bn(&x, "1d4315e38499d6f69f49618aaeecf24f");
BN_hex2bn(&y, "b51a86cff90e01af3a9a52b3c6582c48");
/* create EC point from X and Y */
point = EC_POINT_new(group);
EC_POINT_set_affine_coordinates_GFp(group, point, x, y, NULL);
/* Create a new EC key and set the public key */
key = EC_KEY_new();
EC_KEY_set_group(key, group);
EC_KEY_set_public_key(key, point);
out = BIO_new(BIO_s_file());
BIO_set_fp(out, stdout, BIO_NOCLOSE);
PEM_write_bio_EC_PUBKEY(out, key);
/* Clean up */
BN_free(x);
BN_free(y);
EC_POINT_free(point);
EC_GROUP_free(group);
EC_KEY_free(key);
BIO_free(out);
return 0;
}