Function at 0x40b5d0
Capabilities:
Encode data using xor
Read file on windows
Write file on windows

Disassembly:
push ebp
mov ebp, esp
push 0xffffffffffffffff
push 0x416a60
mov eax, dword fs:[0]
push eax
sub esp, 0x40c
mov eax, dword [0x421018]
xor eax, ebp
mov dword [ebp - 0x10], eax
push ebx
push esi
push edi
push eax
lea eax, [ebp - 0xc]
mov dword fs:[0], eax
mov dword [ebp - 4], 1
mov eax, dword [ebp + 8]
mov edi, 0x10
mov word [ebp - 0x414], 0
cmp dword [ebp + 0x1c], edi
jae 0x40b61e
lea eax, [ebp + 8]
push 0x41b4b8
push eax
call dword [sym.imp.MSVCR100.dll_fopen]
mov esi, eax
add esp, 8
test esi, esi
jne 0x40b680
push str.ComputeAndSaveFileChecksum__:__ERROR__Open_data_file_fail_
push 0x421108
call fcn.00404280
mov esi, dword [sym.imp.MSVCR100.dll_void___cdecl_operator_delete_void__]
add esp, 8
cmp dword [ebp + 0x1c], edi
jb 0x40b659
mov eax, dword [ebp + 8]
push eax
call esi
add esp, 4
mov dword [ebp + 0x1c], 0xf
mov dword [ebp + 0x18], 0
mov byte [ebp + 8], 0
cmp dword [ebp + 0x38], edi
jb 0x40b679
mov ecx, dword [ebp + 0x24]
push ecx
call esi
add esp, 4
xor al, al
jmp 0x40b7d2
push esi
xor bl, bl
call dword [sym.imp.MSVCR100.dll_feof]
add esp, 4
test eax, eax
jne 0x40b6da
mov edi, dword [sym.imp.MSVCR100.dll_fread]
jmp 0x40b6a0
push esi
push 0x400
lea edx, [ebp - 0x410]
push 1
push edx
call edi
add esp, 0x10
xor ecx, ecx
test eax, eax
je 0x40b6cc
lea ebx, [ebx]
xor bl, byte [ebp + ecx - 0x410]
inc ecx
cmp ecx, eax
jb 0x40b6c0
push esi
call dword [sym.imp.MSVCR100.dll_feof]
add esp, 4
test eax, eax
je 0x40b6a0
movzx eax, bl
push eax
push str.ComputeAndSaveFileChecksum__:_Checksum__d_
push 0x421108
call fcn.00404280
mov edi, dword [sym.imp.MSVCR100.dll_fclose]
add esp, 0xc
push esi
call edi
mov eax, dword [ebp + 0x24]
mov byte [ebp - 0x414], bl
mov ebx, 0x10
add esp, 4
cmp dword [ebp + 0x38], ebx
jae 0x40b712
lea eax, [ebp + 0x24]
push 0x41b524
push eax
call dword [sym.imp.MSVCR100.dll_fopen]
mov esi, eax
add esp, 8
test esi, esi
jne 0x40b775
push str.ComputeAndSaveFileChecksum__:__ERROR__Open_checksum_file_fail_
push 0x421108
call fcn.00404280
mov esi, dword [sym.imp.MSVCR100.dll_void___cdecl_operator_delete_void__]
add esp, 8
cmp dword [ebp + 0x1c], ebx
jb 0x40b74d
mov ecx, dword [ebp + 8]
push ecx
call esi
add esp, 4
mov dword [ebp + 0x1c], 0xf
mov dword [ebp + 0x18], 0
mov byte [ebp + 8], 0
cmp dword [ebp + 0x38], ebx
jb 0x40b679
mov edx, dword [ebp + 0x24]
push edx
call esi
add esp, 4
xor al, al
jmp 0x40b7d2
push esi
push 2
lea eax, [ebp - 0x414]
push 1
push eax
call dword [sym.imp.MSVCR100.dll_fwrite]
add esp, 0x10
cmp eax, 2
je 0x40b796
push str.ComputeAndSaveFileChecksum__:__ERROR__Write_checksum_file_fail_
jmp 0x40b72c
push esi
call edi
mov esi, dword [sym.imp.MSVCR100.dll_void___cdecl_operator_delete_void__]
add esp, 4
cmp dword [ebp + 0x1c], ebx
jb 0x40b7b0
mov eax, dword [ebp + 8]
push eax
call esi
add esp, 4
mov dword [ebp + 0x1c], 0xf
mov dword [ebp + 0x18], 0
mov byte [ebp + 8], 0
cmp dword [ebp + 0x38], ebx
jb 0x40b7d0
mov ecx, dword [ebp + 0x24]
push ecx
call esi
add esp, 4
mov al, 1
mov ecx, dword [ebp - 0xc]
mov dword fs:[0], ecx
pop ecx
pop edi
pop esi
pop ebx
mov ecx, dword [ebp - 0x10]
xor ecx, ebp
call fcn.00415aec
mov esp, ebp
pop ebp
ret 0x38