[Help]Alittle help please(5165)

Native.memcpy(p, p2, DataLen);

public unsafe class Native
    {
        [DllImport("kernel32.dll")]
        public static extern IntPtr GetStdHandle(uint nStdHandle);
        [DllImport("kernel32.dll")]
        public static extern bool SetConsoleTextAttribute(IntPtr hConsoleOutput, int wAttributes);
        [DllImport("msvcrt.dll", EntryPoint = "memcpy", CallingConvention = CallingConvention.Cdecl, SetLastError = false)]
        public static extern unsafe void* memcpy(void* dest, void* src, uint size);
        [DllImport("user32.dll")]
        public static extern int MessageBox(int h, string m, string c, int type);
        [DllImport("winmm.dll")]
        public static extern uint timeGetTime();
        [DllImport("libeay32.dll", CallingConvention = CallingConvention.Cdecl)]
        public extern static void BF_set_key(IntPtr _key, int len, byte[] data);
        [DllImport("libeay32.dll", CallingConvention = CallingConvention.Cdecl)]
        public extern static void BF_ecb_encrypt(byte[] in_, byte[] out_, IntPtr schedule, int enc);
        [DllImport("libeay32.dll", CallingConvention = CallingConvention.Cdecl)]
        public extern static void BF_cbc_encrypt(byte[] in_, byte[] out_, int length, IntPtr schedule, byte[] ivec, int enc);
        [DllImport("libeay32.dll", CallingConvention = CallingConvention.Cdecl)]
        public extern static void BF_cfb64_encrypt(byte[] in_, byte[] out_, int length, IntPtr schedule, byte[] ivec, ref int num, int enc);
        [DllImport("libeay32.dll", CallingConvention = CallingConvention.Cdecl)]
        public extern static void BF_ofb64_encrypt(byte[] in_, byte[] out_, int length, IntPtr schedule, byte[] ivec, out int num);
    }