From the look of it, the files are encrypted with DES. The libslua.so file has the key and functions in it to encode buffers using the same setup and key.
Code:
void __cdecl desECode(void *a1, size_t a2, void *a3)
{
int v3; // esi
size_t n; // edi
char *v5; // esi
size_t v6; // ebp
_BYTE *src; // ST04_4
unsigned int *dest; // ST00_4
InitDes();
v3 = dword_42024;
memcpy(a3, "czjzgqde", dword_42024);
*(_DWORD *)((char *)a3 + v3) = a2;
n = desECodeLenth(a2);
v5 = (char *)malloc(n);
memset(v5, 1, n);
v6 = 0;
memcpy(v5, a1, a2);
deskey(byte_42018, 0);
if ( n )
{
do
{
src = (char *)a3 + v6 + dword_42020;
dest = (unsigned int *)&v5[v6];
v6 += 8;
des(dest, src);
}
while ( n > v6 );
}
free(v5);
}
I don't have the time to reverse and test the rest of the process to decrypt the data but it looks like everything you'd need is there.