Imports System.IO
Imports System.Security.Cryptography
Imports System.Text

Public Class frmMain
Enum HashType
MD5
SHA1
SHA256
SHA384
SHA512
End Enum

Private Sub GroupCompare_CheckedChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles radFiles.CheckedChanged, radStrings.CheckedChanged
ClearForm()
Select Case CType(sender, Control).Tag
Case "Files"
lblValue1.Text = "File 1:"
lblValue2.Text = "File 2:"
txtValue1.ReadOnly = True
txtValue2.ReadOnly = True
btnValue1.Visible = True
btnValue2.Visible = True
Case "Strings"
lblValue1.Text = "String 1:"
lblValue2.Text = "String 2:"
txtValue1.ReadOnly = False
txtValue2.ReadOnly = False
btnValue1.Visible = False
btnValue2.Visible = False
End Select
End Sub

Private Sub txt_TextChanged(ByVal sender As Object, ByVal e As System.EventArgs) _
Handles txtValue1.TextChanged, txtValue2.TextChanged, _
txtResults1.TextChanged, txtResults2.TextChanged

ToolTip1.SetToolTip(CType(sender, Control), CType(sender, Control).Text)

End Sub

Private Sub btnFile_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnValue1.Click, btnValue2.Click
If ofdFiles.ShowDialog Then
Select Case CType(sender, Button).Tag
Case 0
txtValue1.Text = ofdFiles.FileName
Case 1
txtValue2.Text = ofdFiles.FileName
End Select
End If
End Sub

Private Sub ClearForm()
txtValue1.Text = ""
txtValue2.Text = ""
txtResults1.Text = ""
txtResults2.Text = ""
End Sub

Private Sub btnCompare_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnCompare.Click
Dim myCursor As Cursor
Dim hasht As hashtype

myCursor = Cursor
Cursor = Cursors.WaitCursor
Try
If radMD5.Checked Then
hasht = hashtype.MD5
End If
If radSHA1.Checked Then
hasht = hashtype.SHA1
End If
If radSHA256.Checked Then
hasht = hashtype.SHA256
End If
If radSHA384.Checked Then
hasht = hashtype.SHA384
End If
If radSHA512.Checked Then
hasht = hashtype.SHA512
End If

If radFiles.Checked Then
txtResults1.Text = GetFileHash(txtValue1.Text, hasht)
txtResults2.Text = GetFileHash(txtValue2.Text, hasht)
ElseIf radStrings.Checked Then
txtResults1.Text = GetStringHash(txtValue1.Text, hasht)
txtResults2.Text = GetStringHash(txtValue2.Text, hasht)
End If

If (String.Compare(txtResults1.Text, txtResults2.Text) = 0) Then
picResult.Image = ImageList1.Images(1)
Else
picResult.Image = ImageList1.Images(0)
End If
Catch ex As Exception
MessageBox.Show(ex.Message, ex.Source, MessageBoxButtons.OK, MessageBoxIcon.Error)
Finally
Cursor = myCursor
End Try
End Sub

Private Function GetFileHash(ByVal filename As String, ByVal hasht As hashtype) As String
Dim oFileStream As System.IO.FileStream
Dim lBytes As Long

Try
If filename <> "" Then
Dim instance As New FileInfo(filename)
oFileStream = instance.OpenRead()
lBytes = oFileStream.Length
Dim filecontents(lBytes) As Byte
oFileStream.Read(filecontents, 0, lBytes)
oFileStream.Close()

Return GetHash(filecontents, hasht)
Else
Return ""
End If
Catch ex As Exception
MessageBox.Show(ex.Message, ex.Source, MessageBoxButtons.OK, MessageBoxIcon.Error)
Return ""
End Try

End Function

Private Function GetStringHash(ByVal input As String, ByVal hasht As hashtype) As String

Return GetHash(Encoding.Default.GetBytes(input), hasht)

End Function

Public Function GetHash(ByRef contents As Byte(), ByVal hasht As hashtype) As String
Dim result() As Byte

Select Case hasht
Case hashtype.MD5
Dim MD5 As MD5 = MD5.Create
result = MD5.ComputeHash(contents)
Case hashtype.SHA1
Dim sha1M As New SHA1Managed
result = sha1M.ComputeHash(contents)
Case hashtype.SHA256
Dim sha256M As New SHA256Managed
result = sha256M.ComputeHash(contents)
Case hashtype.SHA384
Dim sha384M As New SHA384Managed
result = sha384M.ComputeHash(contents)
Case hashtype.SHA512
Dim sha512M As New SHA512Managed
result = sha512M.ComputeHash(contents)
End Select

Return GetByteString(result)
End Function

Public Function GetByteString(ByVal data As Byte())
Dim sBuilder As New StringBuilder()
Dim i As Integer

For i = 0 To data.Length - 1
sBuilder.Append(data(i).ToString("x2"))
Next i
Return sBuilder.ToString()
End Function
End Class