我正在尝试加载我从SGX
飞机上获得的公共密钥到OpenSSL
椭圆曲线公共密钥对象。
SGX SDK
中内置的加密库将SECP256R1
上的点用于公共密钥,并将其表示为(x,y(对。所以我试图做以下操作:
1(从 SGX
对象提取仿射坐标(x,y(。
2(在SECP256R1
上创建一个OpenSSL公共密钥对象。
3(将其设置为(x,y(。
最后一个呼叫,错误消息失败:"error:1007C06B:elliptic curve routines:EC_POINT_set_affine_coordinates_GFp:point is not on curve"
。这在哪里可以出错?可以是一个终点问题吗?
#include <stdio.h>
#include <sgx_tcrypto.h>
#include <openssl/obj_mac.h>
#include <openssl/ec.h>
#include <openssl/err.h>
const sgx_ec256_public_t sgx_pk;
const sgx_ec256_private_t sgx_sk;
int main()
{
//init openssl objects
EC_GROUP *group = EC_GROUP_new_by_curve_name(NID_X9_62_prime256v1); //assuming this the same as secp256r1
BN_CTX *bn_ctx = BN_CTX_new();
//extract affine coordinates from sgx object
BIGNUM *x = BN_bin2bn((uint8_t*)&sgx_pk.gx, sizeof(sgx_pk) / 2, NULL);
BIGNUM *y = BN_bin2bn((uint8_t*)&sgx_pk.gy, sizeof(sgx_pk) / 2, NULL);
//create openssl key and load the coordinates into it
EC_KEY *ec_key = EC_KEY_new();
EC_KEY_set_group(ec_key, group);
EC_KEY_set_public_key_affine_coordinates(ec_key, x, y);
//last call fails. extract error
long error_code = ERR_get_error();
char error_string[300];
ERR_error_string_n(error_code, error_string, sizeof(error_string));
puts(error_string);
return 0;
}
供参考,这里定义了一个示例键对:
const sgx_ec256_private_t sgx_sk =
{
0xc1, 0xe7, 0x59, 0x90, 0x4e, 0x80, 0xa5, 0x52,
0x45, 0x25, 0xec, 0x2a, 0xc, 0x98, 0x89, 0x6e,
0x63, 0x96, 0x4d, 0x5d, 0x58, 0x48, 0x86, 0xf4,
0x9b, 0x70, 0xad, 0xb5, 0xa2, 0x56, 0xe9, 0x13
};
const sgx_ec256_public_t sgx_pk =
{
0x82, 0xcb, 0x6f, 0x41, 0x3a, 0xd4, 0xfa, 0x57,
0x6c, 0xc4, 0x1b, 0x77, 0xf6, 0xd9, 0x51, 0xc1,
0xbc, 0x17, 0x7a, 0x88, 0xd0, 0x2e, 0x94, 0xd6,
0x91, 0xa3, 0x1d, 0x75, 0xc, 0xbf, 0xa9, 0xca,
0x8, 0x6c, 0xf3, 0x78, 0x92, 0xdb, 0x2f, 0x52,
0x0, 0x44, 0x20, 0xd6, 0xa, 0xd3, 0x58, 0x3,
0xb2, 0x35, 0xda, 0xe2, 0x1b, 0xdb, 0x2b, 0xd2,
0xb0, 0xaf, 0x5e, 0x29, 0xc8, 0xb4, 0x93, 0x41
};
这确实是一个端的问题。以下C 代码有效:
#include <stdio.h>
#include <algorithm>
#include <openssl/obj_mac.h>
#include <openssl/ec.h>
#include <openssl/err.h>
#include <sgx_tcrypto.h>
extern const sgx_ec256_public_t sgx_pk;
extern const sgx_ec256_private_t sgx_sk;
int main()
{
//init openssl objects
EC_GROUP *group = EC_GROUP_new_by_curve_name(NID_X9_62_prime256v1);
//assuming this the same as secp256r1
BN_CTX *bn_ctx = BN_CTX_new();
//extract affine coordinates from sgx object
sgx_ec256_public_t sgx_pk_reversed;
constexpr size_t COORDINATE_SIZE = sizeof(sgx_ec256_public_t) / 2;
std::reverse_copy(sgx_pk.gx, sgx_pk.gx + COORDINATE_SIZE, sgx_pk_reversed.gx);
std::reverse_copy(sgx_pk.gy, sgx_pk.gy + COORDINATE_SIZE, sgx_pk_reversed.gy);
BIGNUM *x = BN_bin2bn((uint8_t*)&sgx_pk_reversed.gx, COORDINATE_SIZE, NULL);
BIGNUM *y = BN_bin2bn((uint8_t*)&sgx_pk_reversed.gy, COORDINATE_SIZE, NULL);
//create openssl key and load the coordinates into it
EC_KEY *ec_key = EC_KEY_new();
EC_KEY_set_group(ec_key, group);
if (1 == EC_KEY_set_public_key_affine_coordinates(ec_key, x, y))
puts("Holy shit it worked.");
return 0;
}