#include <windows.h>
#include <stdio.h>
#include <wincrypt.h>
#pragma comment (lib, "crypt32.lib")
#pragma comment (lib, "advapi32")


int AESDecrypt(char * payload, unsigned int payload_len, char * key, size_t keylen) {
    HCRYPTPROV hProv;
    HCRYPTHASH hHash;
    HCRYPTKEY hKey;

    if (!CryptAcquireContextW(&hProv, NULL, NULL, PROV_RSA_AES, CRYPT_VERIFYCONTEXT)){
            return -1;
    }
    if (!CryptCreateHash(hProv, CALG_SHA_256, 0, 0, &hHash)){
            return -1;
    }
    if (!CryptHashData(hHash, (BYTE*)key, (DWORD)keylen, 0)){
            return -1;              
    }
    if (!CryptDeriveKey(hProv, CALG_AES_256, hHash, 0,&hKey)){
            return -1;
    }
    
    if (!CryptDecrypt(hKey, (HCRYPTHASH) NULL, 0, 0, payload, &payload_len)){
            return -1;
    }
    
    CryptReleaseContext(hProv, 0);
    CryptDestroyHash(hHash);
    CryptDestroyKey(hKey);
	
    return 0;
}

int main(void)
{
	

	char AESkey[] = { 0x91, 0x55, 0xee, 0x3f, 0x32, 0x29, 0xae, 0x62, 0x8e, 0x83, 0x10, 0xe1, 0x7c, 0x37, 0x83, 0xd5 };

char shellcode[] = { 0x1c, 0xf7, 0x86, 0xa5, 0x78, 0x50, 0xce, 0x38, 0x95, 0x21, 0xeb, 0x7c, 0x49, 0xe3, 0x8d, 0xcd, 0x92, 0x70, 0x4c, 0x8a, 0xb1, 0xf5, 0xfc, 0xb8, 0xf8, 0x86, 0xfd, 0xf4, 0x67, 0x10, 0xc, 0xd4, 0xa2, 0x2f, 0x2d, 0x78, 0x2d, 0xcf, 0x21, 0x8d, 0x60, 0xb4, 0x9, 0x15, 0x4, 0x16, 0x98, 0xaf };

	AESDecrypt((char *) shellcode, sizeof(shellcode), AESkey, sizeof(AESkey));

	int idx = 0;
	while ( idx < sizeof(shellcode))
	{
		if (idx == (sizeof(shellcode) - 1) )
		{
			printf("0x%02x ", (unsigned char)shellcode[idx]);
		}
		else
		{
			printf("0x%02x, ", (unsigned char)shellcode[idx]);
		}
		idx++;
	}
	
	return 0;
}