Function at 0x503a80
Capabilities:
Get file size
Hash data via wincrypt
Hash data with md5
Initialize hashing via wincrypt
Read file on windows

Disassembly:
push ecx
mov eax, dword [esp + 8]
push ebx
push ebp
push esi
test eax, eax
push edi
mov ebp, ecx
jne 0x503aa0
pop edi
mov dword [ebp + 0x44], 1
pop esi
pop ebp
xor al, al
pop ebx
pop ecx
ret 8
cmp byte [eax], 0
jne 0x503ab6
pop edi
mov dword [ebp + 0x44], 2
pop esi
pop ebp
xor al, al
pop ebx
pop ecx
ret 8
push 0
push 0x80
push 3
push 0
push 3
push closesocket
push eax
call dword [sym.imp.KERNEL32.dll_CreateFileA]
mov esi, eax
cmp esi, 0xffffffff
jne 0x503ae7
pop edi
mov dword [ebp + 0x44], 3
pop esi
pop ebp
xor al, al
pop ebx
pop ecx
ret 8
push 0
push esi
call dword [sym.imp.KERNEL32.dll_GetFileSize]
cmp eax, 0xffffffff
mov dword [ebp + 0x24], eax
jne 0x503b10
push esi
call dword [sym.imp.KERNEL32.dll_CloseHandle]
pop edi
mov dword [ebp + 0x44], 0x21
pop esi
pop ebp
xor al, al
pop ebx
pop ecx
ret 8
mov eax, dword [ebp + 4]
test eax, eax
je 0x503b27
push eax
call fcn.005050dd
add esp, 4
mov dword [ebp + 4], 0
mov eax, dword [ebp + 0x24]
push eax
call fcn.00505776
add esp, 4
mov dword [ebp + 4], eax
test eax, eax
jne 0x503b52
push esi
call dword [sym.imp.KERNEL32.dll_CloseHandle]
pop edi
mov dword [ebp + 0x44], 4
pop esi
pop ebp
xor al, al
pop ebx
pop ecx
ret 8
mov edx, dword [ebp + 0x24]
lea ecx, [esp + 0x10]
push 0
push ecx
push edx
push eax
push esi
call dword [sym.imp.KERNEL32.dll_ReadFile]
mov eax, dword [ebp + 0x24]
mov ecx, dword [esp + 0x10]
cmp ecx, eax
je 0x503b88
push esi
call dword [sym.imp.KERNEL32.dll_CloseHandle]
pop edi
mov dword [ebp + 0x44], 5
pop esi
pop ebp
xor al, al
pop ebx
pop ecx
ret 8
mov edx, dword [ebp + 4]
lea ecx, [ebp + 0x28]
mov edi, ecx
lea edx, [edx + eax - 0x10]
mov ebx, dword [edx]
mov dword [edi], ebx
mov ebx, dword [edx + 4]
mov dword [edi + 4], ebx
mov ebx, dword [edx + 8]
mov dword [edi + 8], ebx
mov edx, dword [edx + 0xc]
mov dword [edi + 0xc], edx
mov edx, dword [ecx]
cmp edx, 0x32812622
jne 0x503bdc
cmp dword [ebp + 0x34], 0x32812621
jne 0x503bdc
mov ecx, dword [ebp + 0x2c]
mov edx, dword [ebp + 0x30]
mov edi, eax
mov byte [ebp + 0x1c], 1
lea edx, [edx + ecx + 0x10]
mov dword [ebp + 0x38], ecx
sub edi, edx
mov dword [ebp + 0x20], edx
mov dword [ebp + 8], edi
xor ebx, ebx
jmp 0x503bfa
xor eax, eax
xor ebx, ebx
mov dword [ecx], eax
mov dword [ecx + 4], eax
mov dword [ecx + 8], eax
mov dword [ecx + 0xc], eax
mov eax, dword [ebp + 0x24]
mov byte [ebp + 0x1c], bl
mov dword [ebp + 0x20], ebx
mov dword [ebp + 8], eax
mov dword [ebp + 0x38], ebx
cmp eax, dword [ebp + 0x20]
jae 0x503c0e
mov byte [ebp + 0x1c], bl
mov dword [ebp + 0x20], ebx
mov dword [ebp + 0x24], ebx
mov dword [ebp + 8], ebx
mov dword [ebp + 0x38], ebx
push esi
call dword [sym.imp.KERNEL32.dll_CloseHandle]
cmp byte [ebp + 0x1c], bl
jne 0x503c2b
pop edi
mov dword [ebp + 0x44], 6
pop esi
pop ebp
xor al, al
pop ebx
pop ecx
ret 8
mov eax, dword [ebp + 0x14]
mov ecx, dword [ebp + 0x30]
cmp eax, ebx
mov dword [ebp + 0x18], ecx
je 0x503c44
push eax
call fcn.005050dd
add esp, 4
mov dword [ebp + 0x14], ebx
mov edx, dword [ebp + 0x18]
push edx
call fcn.00505776
add esp, 4
cmp eax, ebx
mov dword [ebp + 0x14], eax
jne 0x503c68
pop edi
mov dword [ebp + 0x44], 7
pop esi
pop ebp
xor al, al
pop ebx
pop ecx
ret 8
mov esi, dword [ebp + 8]
mov edx, dword [ebp + 4]
mov edi, dword [ebp + 0x38]
mov ecx, dword [ebp + 0x18]
add esi, edx
add esi, edi
mov edi, eax
mov eax, ecx
shr ecx, 2
rep movsd dword es:[edi], dword [esi]
mov ecx, eax
and ecx, 3
rep movsb byte es:[edi], byte [esi]
cmp dword [ebp], ebx
jne 0x503cb6
push 0xf0000000
push 1
push str.Microsoft_Base_Cryptographic_Provider_v1.0
push ebx
push ebp
call dword [sym.imp.ADVAPI32.dll_CryptAcquireContextA]
test eax, eax
jne 0x503cb6
pop edi
mov dword [ebp + 0x44], 8
pop esi
pop ebp
xor al, al
pop ebx
pop ecx
ret 8
mov eax, dword [ebp + 0x10]
lea edi, [ebp + 0x10]
cmp eax, ebx
je 0x503cc9
push eax
call dword [sym.imp.ADVAPI32.dll_CryptDestroyKey]
mov dword [edi], ebx
mov ecx, dword [0x5508e0]
mov edx, dword [ebp]
mov esi, dword [sym.imp.ADVAPI32.dll_CryptImportKey]
push edi
push ebx
push ebx
push ecx
push 0x55088c
push edx
call esi
test eax, eax
jne 0x503d45
call dword [sym.imp.KERNEL32.dll_GetLastError]
cmp eax, 0x57
jne 0x503d34
push 0xf0000000
push 1
push str.Microsoft_Base_Cryptographic_Provider_v1.0
push ebx
push ebp
call dword [sym.imp.ADVAPI32.dll_CryptAcquireContextA]
test eax, eax
jne 0x503d1c
pop edi
mov dword [ebp + 0x44], 0x62
pop esi
pop ebp
xor al, al
pop ebx
pop ecx
ret 8
mov eax, dword [0x5508e0]
mov ecx, dword [ebp]
push edi
push ebx
push ebx
push eax
push 0x55088c
push ecx
call esi
test eax, eax
jne 0x503d45
pop edi
mov dword [ebp + 0x44], 9
pop esi
pop ebp
xor al, al
pop ebx
pop ecx
ret 8
mov eax, dword [ebp + 0xc]
lea esi, [ebp + 0xc]
cmp eax, ebx
je 0x503d58
push eax
call dword [sym.imp.ADVAPI32.dll_CryptDestroyHash]
mov dword [esi], ebx
mov edx, dword [ebp]
push esi
push ebx
push ebx
push 0x8003
push edx
call dword [sym.imp.ADVAPI32.dll_CryptCreateHash]
test eax, eax
jne 0x503d7f
pop edi
mov dword [ebp + 0x44], 0xa
pop esi
pop ebp
xor al, al
pop ebx
pop ecx
ret 8
mov eax, dword [ebp + 8]
mov edx, dword [ebp + 0x38]
mov ecx, dword [ebp + 4]
add eax, edx
mov edx, dword [esi]
push ebx
push eax
push ecx
push edx
call dword [sym.imp.ADVAPI32.dll_CryptHashData]
test eax, eax
jne 0x503dab
pop edi
mov dword [ebp + 0x44], 0xb
pop esi
pop ebp
xor al, al
pop ebx
pop ecx
ret 8
mov eax, dword [edi]
mov ecx, dword [ebp + 0x18]
mov edx, dword [ebp + 0x14]
push ebx
push ebx
push eax
mov eax, dword [esi]
push ecx
push edx
push eax
call dword [sym.imp.ADVAPI32.dll_CryptVerifySignatureA]
test eax, eax
jne 0x503e24
call dword [sym.imp.KERNEL32.dll_GetLastError]
cmp eax, 0x57
jne 0x503e13
push 0xf0000000
push 1
push str.Microsoft_Base_Cryptographic_Provider_v1.0
push ebx
push ebp
call dword [sym.imp.ADVAPI32.dll_CryptAcquireContextA]
test eax, eax
jne 0x503df9
pop edi
mov dword [ebp + 0x44], 0x80
pop esi
pop ebp
xor al, al
pop ebx
pop ecx
ret 8
mov ecx, dword [edi]
mov edx, dword [ebp + 0x18]
mov eax, dword [ebp + 0x14]
push ebx
push ebx
push ecx
mov ecx, dword [esi]
push edx
push eax
push ecx
call dword [sym.imp.ADVAPI32.dll_CryptVerifySignatureA]
test eax, eax
jne 0x503e24
pop edi
mov dword [ebp + 0x44], 0xc
pop esi
pop ebp
xor al, al
pop ebx
pop ecx
ret 8
cmp byte [esp + 0x1c], bl
je 0x503e6d
mov esi, dword [esp + 0x18]
push 0x5c
push esi
call fcn.00508550
add esp, 8
cmp eax, ebx
je 0x503e40
inc eax
jmp 0x503e42
mov eax, esi
mov edx, dword [ebp + 0x38]
mov ecx, dword [ebp + 8]
push edx
mov edx, dword [ebp + 4]
add ecx, edx
push ecx
push eax
call fcn.00508440
add esp, 0xc
test eax, eax
je 0x503e6d
pop edi
mov dword [ebp + 0x44], 0xd
pop esi
pop ebp
xor al, al
pop ebx
pop ecx
ret 8
mov eax, dword [ebp + 4]
cmp eax, ebx
je 0x503e80
push eax
call fcn.005050dd
add esp, 4
mov dword [ebp + 4], ebx
pop edi
pop esi
pop ebp
mov al, 1
pop ebx
pop ecx
ret 8