ECC key generation example using openssl

[Indtiny S]

Dear All,

I have written below code to generate a ECC based private and public key .

But I am missing logic , my keys are not generated .

My goal is to generate , Client :- private = Ca , public= Ca,G and Server:-
private=Sa, pub = Sa.G

and prove Ca.(Sa.G) = Sa.(CaG)



 #include <openssl/obj_mac.h>
 #include <openssl/ec.h>

void handleErrors(void){

printf("\n error ");
}
EC_GROUP *create_curve(void)
{
BN_CTX *ctx;
EC_GROUP *curve;
BIGNUM *a, *b, *p, *order, *x, *y;
EC_POINT *generator;

/* Binary data for the curve parameters */
unsigned char a_bin[28] =
{0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
0xFF,0xFF,0xFF,0xFF,0xFF,0xFE,0xFF,0xFF,0xFF,0xFF,
0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFE};
unsigned char b_bin[28] =
{0xB4,0x05,0x0A,0x85,0x0C,0x04,0xB3,0xAB,0xF5,0x41,
0x32,0x56,0x50,0x44,0xB0,0xB7,0xD7,0xBF,0xD8,0xBA,
0x27,0x0B,0x39,0x43,0x23,0x55,0xFF,0xB4};
unsigned char p_bin[28] =
{0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0x00,0x00,0x00,0x00,
0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x01};
unsigned char order_bin[28] =
{0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
0xFF,0xFF,0xFF,0xFF,0x16,0xA2,0xE0,0xB8,0xF0,0x3E,
0x13,0xDD,0x29,0x45,0x5C,0x5C,0x2A,0x3D };
unsigned char x_bin[28] =
{0xB7,0x0E,0x0C,0xBD,0x6B,0xB4,0xBF,0x7F,0x32,0x13,
0x90,0xB9,0x4A,0x03,0xC1,0xD3,0x56,0xC2,0x11,0x22,
0x34,0x32,0x80,0xD6,0x11,0x5C,0x1D,0x21};
unsigned char y_bin[28] =
{0xbd,0x37,0x63,0x88,0xb5,0xf7,0x23,0xfb,0x4c,0x22,
0xdf,0xe6,0xcd,0x43,0x75,0xa0,0x5a,0x07,0x47,0x64,
0x44,0xd5,0x81,0x99,0x85,0x00,0x7e,0x34};

/* Set up the BN_CTX */
if(NULL == (ctx = BN_CTX_new())) handleErrors();

/* Set the values for the various parameters */
if(NULL == (a = BN_bin2bn(a_bin, 28, NULL))) handleErrors();
if(NULL == (b = BN_bin2bn(b_bin, 28, NULL))) handleErrors();
if(NULL == (p = BN_bin2bn(p_bin, 28, NULL))) handleErrors();
if(NULL == (order = BN_bin2bn(order_bin, 28, NULL))) handleErrors();
if(NULL == (x = BN_bin2bn(x_bin, 28, NULL))) handleErrors();
if(NULL == (y = BN_bin2bn(y_bin, 28, NULL))) handleErrors();

/* Create the curve */
if(NULL == (curve = EC_GROUP_new_curve_GFp(p, a, b, ctx))) handleErrors();

/* Create the generator */
if(NULL == (generator = EC_POINT_new(curve))) handleErrors();
if(1 != EC_POINT_set_affine_coordinates_GFp(curve, generator, x, y, ctx))
handleErrors();

/* Set the generator and the order */
if(1 != EC_GROUP_set_generator(curve, generator, order, NULL))
handleErrors();

EC_POINT_free(generator);
BN_free(y);
BN_free(x);
BN_free(order);
BN_free(p);
BN_free(b);
BN_free(a);
BN_CTX_free(ctx);

return curve;
}


void myPrint( BIGNUM * x, char * t ) {
   char * s = BN_bn2dec( x ) ;
   printf("%s%s", s, t ) ;
//   OPENSSL_free(s) ;
   free(s) ;
}

int main()
{
EC_GROUP * cur = create_curve();
if(NULL == cur)
{
handleErrors();
}

EC_KEY *key;

if(NULL == (key = EC_KEY_new_by_curve_name(NID_secp224r1)))
handleErrors();

if(1 != EC_KEY_generate_key(key)) handleErrors();

BIGNUM *prv;
EC_POINT *pub;

/* Set up private key in prv */
/* Set up public key in pub */

if(1 != EC_KEY_set_private_key(key, prv)) handleErrors();

myPrint(prv,"\n");
if(1 != EC_KEY_set_public_key(key, pub)) handleErrors();

return 0;

}