C++ Windows CryptDecrypt always return successful

Question

Im having the code below but no matter what i pass as key the CryptDecrypt always return 1/TRUE, I have problem checking if the provided key is correct or not.

void DecryptAES(char* content, DWORD contentlen, char* key, DWORD keyLen) {
    HCRYPTPROV hProv;
    HCRYPTHASH hHash;
    HCRYPTKEY hKey;

    if (!CryptAcquireContextW(&hProv, NULL, NULL, PROV_RSA_AES, CRYPT_VERIFYCONTEXT)) {
        printf("Failed in CryptAcquireContextW (%u)\n", GetLastError());
        return;
    }
    if (!CryptCreateHash(hProv, CALG_SHA_256, 0, 0, &hHash)) {
        printf("Failed in CryptCreateHash (%u)\n", GetLastError());
        return;
    }
    if (!CryptHashData(hHash, (BYTE*)key, keyLen, 0)) {
        printf("Failed in CryptHashData (%u)\n", GetLastError());
        return;
    }
    if (!CryptDeriveKey(hProv, CALG_AES_256, hHash, 0, &hKey)) {
        printf("Failed in CryptDeriveKey (%u)\n", GetLastError());
        return;
    }

    if (!CryptDecrypt(hKey, (HCRYPTHASH)NULL, 0, 0, (BYTE*)content, &contentlen)) {
        printf("Failed in CryptDecrypt (%u)\n", GetLastError());
        return;
    }

    CryptReleaseContext(hProv, 0);
    CryptDestroyHash(hHash);
    CryptDestroyKey(hKey);

}

What is wrong with this code?

Thanks