int SM2_decrypt(int type, const unsigned char *in, size_t inlen,
unsigned char *out, size_t *outlen, EC_KEY *ec_key)
{
int ret = 0;
SM2CiphertextValue *cv = NULL;
const EVP_MD *md;
if (!in) {
SM2err(SM2_F_SM2_DECRYPT, ERR_R_PASSED_NULL_PARAMETER);
return 0;
}
if (inlen <= 0 || inlen > INT_MAX) {
SM2err(SM2_F_SM2_DECRYPT, SM2_R_INVALID_INPUT_LENGTH);
return 0;
}
if (!out) {
*outlen = inlen;
return 1;
} else if (*outlen < inlen) {
SM2err(SM2_F_SM2_DECRYPT, SM2_R_BUFFER_TOO_SMALL);
return 0;
}
if (!(md = EVP_get_digestbynid(type))) {
SM2err(SM2_F_SM2_DECRYPT, SM2_R_INVALID_DIGEST_ALGOR);
return 0;
}
if (!(cv = d2i_SM2CiphertextValue(NULL, &in, (long)inlen))) {
SM2err(SM2_F_SM2_DECRYPT, SM2_R_INVALID_CIPHERTEXT);
return 0;
}
if (inlen != i2d_SM2CiphertextValue(cv, NULL)) {
SM2err(SM2_F_SM2_DECRYPT, SM2_R_INVALID_CIPHERTEXT);
goto end;
}
if (!SM2_do_decrypt(md, cv, out, outlen, ec_key)) {
SM2err(SM2_F_SM2_DECRYPT, SM2_R_DECRYPT_FAILURE);
goto end;
}
ret = 1;
end:
SM2CiphertextValue_free(cv);
return ret;
}
static int test_sm2_enc(void)
{
int rv;
EC_KEY *ec_key = NULL;
char *msg = "Hello world!";
SM2_CIPHERTEXT_VALUE *cv = NULL;
unsigned char ctbuf[512];
unsigned char ptbuf[512];
size_t len, len2;
BIO *bio = BIO_new_fp(stdout, BIO_NOCLOSE);
ec_key = EC_KEY_new_by_curve_name(NID_sm2p256v1);
OPENSSL_assert(ec_key);
rv = EC_KEY_generate_key(ec_key);
OPENSSL_assert(rv == 1);
cv = SM2_do_encrypt(EVP_sm3(), EVP_sm3(), (unsigned char *)msg, (size_t)strlen(msg), ec_key);
OPENSSL_assert(cv);
SM2_CIPHERTEXT_VALUE_print(bio, EC_KEY_get0_group(ec_key), cv, 0, 0);
bzero(ptbuf, sizeof(ptbuf));
len = sizeof(ptbuf);
rv = SM2_do_decrypt(EVP_sm3(), EVP_sm3(), cv, ptbuf, &len, ec_key);
OPENSSL_assert(rv == 1);
len = sizeof(ctbuf);
rv = SM2_encrypt(EVP_sm3(), EVP_sm3(),
SM2_DEFAULT_POINT_CONVERSION_FORM,
(unsigned char *)msg, (size_t)strlen(msg), ctbuf, &len, ec_key);
OPENSSL_assert(rv == 1);
bzero(ptbuf, sizeof(ptbuf));
len2 = sizeof(ptbuf);
rv = SM2_decrypt(EVP_sm3(), EVP_sm3(),
SM2_DEFAULT_POINT_CONVERSION_FORM,
ctbuf, len, ptbuf, &len2, ec_key);
OPENSSL_assert(rv == 1);
/*
printf("original plaintext: %s\n", msg);
printf("decrypted plaintext: %s\n", ptbuf);
*/
printf("%s() success\n", __FUNCTION__);
return 0;
}
int SM2_decrypt(const EVP_MD *kdf_md, const EVP_MD *mac_md,
point_conversion_form_t point_form,
const unsigned char *in, size_t inlen,
unsigned char *out, size_t *outlen, EC_KEY *ec_key)
{
int ret = 0;
const EC_GROUP *ec_group = EC_KEY_get0_group(ec_key);
SM2_CIPHERTEXT_VALUE *cv = NULL;
int len;
if (!(len = SM2_CIPHERTEXT_VALUE_size(ec_group, point_form, 0, mac_md))) {
fprintf(stderr, "%s %d\n", __FILE__, __LINE__);
goto end;
}
if (inlen <= len) {
fprintf(stderr, "%s %d\n", __FILE__, __LINE__);
goto end;
}
if (!out) {
*outlen = inlen - len;
return 1;
} else if (*outlen < inlen - len) {
fprintf(stderr, "%s %d\n", __FILE__, __LINE__);
return 0;
}
if (!(cv = SM2_CIPHERTEXT_VALUE_decode(ec_group, point_form, mac_md, in, inlen))) {
fprintf(stderr, "%s %d\n", __FILE__, __LINE__);
goto end;
}
if (!SM2_do_decrypt(kdf_md, mac_md, cv, out, outlen, ec_key)) {
fprintf(stderr, "%s %d\n", __FILE__, __LINE__);
goto end;
}
ret = 1;
end:
if (cv) SM2_CIPHERTEXT_VALUE_free(cv);
return ret;
}