VBA calculate MD5 hash on file contents - vba

Question

I need a VBA routine to calculate the MD5 hash of a file's contents. I located some examples (e.g., here) but I found that they crashed when the filename contained certain Unicode characters, so I am trying to tweak the code to avoid that.
This code does not result in an error, but it also doesn't return the correct MD5 hash. What's wrong?
Public Function FileToMD5Hex(sFileName As String) As String
Dim enc
Dim bytes
Dim outstr As String
Dim pos As Integer
Set enc = CreateObject("System.Security.Cryptography.MD5CryptoServiceProvider")
'Convert the string to a byte array and hash it
bytes = GetFileBytes(sFileName)
bytes = enc.ComputeHash_2((bytes))
'Convert the byte array to a hex string
For pos = 1 To LenB(bytes)
outstr = outstr & LCase(Right("0" & Hex(AscB(MidB(bytes, pos, 1))), 2))
Next
FileToMD5Hex = outstr
Set enc = Nothing
End Function
Private Function GetFileBytes(path As String) As Byte()
Dim fso As Object
Set fso = CreateObject("scripting.FileSystemObject")
Dim fil As Object
Set fil = fso.GetFile(path)
' Dim fpga As Variant
GetFileBytes = fil.OpenAsTextStream().Read(fil.Size)
Set fil = Nothing
Set fso = Nothing
End Function

Answer 1

There are some chars sequences that Scripting.FileSystemObject can't process properly as TextStream.
Use ADODB.Stream ActiveX to retrieve array of bytes from file. It works perfectly with both text and binary types of data, also it allows to change charset of the string (FSO only works with ASCII and Unicode, and only with files).
Function GetFileBytes(strPath As String) As Byte()
With CreateObject("ADODB.Stream")
.Type = 1 ' adTypeBinary
.Open
.LoadFromFile (strPath)
GetFileBytes = .Read()
End With
End Function
Another one ActiveX processing binary data is SAPI.spFileStream. One of the most significant advantages - it allows to load only the part of the file to the memory (in some cases when comparing large files it can help drastically increase performance, checking md5 by chunks).
Function GetFileBytes(strPath As String) As Byte()
Dim arrContent As Variant
With CreateObject("SAPI.spFileStream")
.Open strPath, 0
.Read arrContent, CreateObject("Scripting.FileSystemObject").GetFile(strPath).Size
.Close
End With
GetFileBytes = arrContent
End Function