Brudvik.org » vb.net

SSH/SFTP client in VB.net with sources

Kjell Arne Brudvik — Wed, 10 Jun 2009 19:11:37 +0000

I was browsing the web and found a open-source library for using SSH/SFTP connections in .NET. Thus I put together this example that contains methods to upload, download and list directories. I’ve made the class easy to use so that you can with ease implement progressbar and such on the transfers. Below you can see a screenshot from the example program.

Download example and sources:

Site Synchronizer (361)

References:

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Store your application config as XML

Kjell Arne Brudvik — Mon, 23 Mar 2009 18:14:12 +0000

As I stated in the previous post, the new project of mine I am rewamping most of my old libraries and the configuration is no different. Usually I stored configuration using old INI files, but well – thats a bit outdated now in 2009. I still wanted a similar way to store and get my configuration; so basically I wanted the INI way of storing configuration though in a XML type of format. After browsing the internet I found some different ways people had solved this, though I also wanted the ability to supply a default value in case the value has not been registered. Also, if the setting had not been set already in the file, it should also be automatically set using the default value. This to make it easier and quicker to build a settings.xml file that can quickly be included with applications.

ProgramSettings.vb

'// Copyright (c) 2009 - Kjell Arne Brudvik
'// Email: kjell.arne@brudvik.org - WWW: http://www.brudvik.org/
'// This is released open-source, free to use for anyone whom wants.
 
Imports System.IO
 
Public Class ProgramSettings
 
    Private filename As String = ""
 
    Public Sub New(ByVal filename As String)
        Me.filename = filename
    End Sub
 
    Public Function getSetting(ByVal key As String, ByVal defaultValue As String) As String
        Try
            Dim data As String = ""
            Dim settings As New DataSet
            If File.Exists(filename) Then
                settings.ReadXml(filename)
            Else
                settings.Tables.Add("settings")
                settings.Tables(0).Columns.Add("key", GetType(String))
                settings.Tables(0).Columns.Add("value", GetType(String))
            End If
            Dim row() As DataRow = settings.Tables("settings").Select("key = '" &amp; key &amp; "'")
            If row.Length = 1 Then data = row(0)("value").ToString
            If data.Trim.Equals("") Then
                data = defaultValue
                Call setSetting(key, defaultValue)
            End If
            Return data
        Catch ex As Exception
            Call setSetting(key, defaultValue)
            Return defaultValue
        End Try
    End Function
 
    Public Sub setSetting(ByVal key As String, ByVal value As String)
        Try
            Dim settings As New DataSet
            If File.Exists(filename) Then
                settings.ReadXml(filename)
            Else
                settings.Tables.Add("settings")
                settings.Tables(0).Columns.Add("key", GetType(String))
                settings.Tables(0).Columns.Add("value", GetType(String))
            End If
            Dim row() As DataRow = settings.Tables(0).Select("key = '" &amp; key &amp; "'")
            If row.Length = 1 Then
                row(0)("value") = value
            Else
                Dim setting As DataRow = settings.Tables("settings").NewRow
                setting("key") = key
                setting("value") = value
                settings.Tables("settings").Rows.Add(setting)
            End If
            settings.WriteXml(filename)
        Catch ex As Exception
 
        End Try
    End Sub
 
End Class

How do I use it?
It’s rather simple to use this Class, and simplicity is what I strive for in the code that I release. As you see below you simply call the constructor with the path for a file, and then using the methods getSetting and setSetting you can easily get and set settings in an XML environment. Thus this class can easily be used to finally get rid of your INI configuration routines.

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Dim settings as ProgramSettings = New ProgramSettings("settings.xml")
Dim value as String = settings.getSetting("author", "Kjell Arne Brudvik")
settings.setSetting("author", "Some other author")

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Encrypt and decrypt files in VB.net

Kjell Arne Brudvik — Mon, 23 Mar 2009 17:58:57 +0000

As I’ve been working on a new project lately, I needed a way to encrypt/decrypt files quickly and easily in VB.net. For some reason I found tons of examples around the internet, but either you had to put them together yourself, or they were poorly coded or coded in a way that seemed like a random mess. Thus I put together this Class that makes it rather easy for you to encrypt/decrypt files. It is based on managed Rijndael and the Class is fairly easy to use.

FileEncryption.vb

'// Copyright (c) 2009 - Kjell Arne Brudvik
'// Email: kjell.arne@brudvik.org - WWW: http://www.brudvik.org/
'// This is released open-source, free to use for anyone whom wants.
 
Imports System
Imports System.IO
Imports System.Security
Imports System.Security.Cryptography
 
Public Class FileEncryption
 
    Private password As String = ""
    Private encryptionKey() As Byte = Nothing
    Private encryptionIV() As Byte = Nothing
    Private inputFile As FileStream = Nothing
    Private outputFile As FileStream = Nothing
 
    Public Sub New(ByVal password As String)
        Me.password = password
        Me.encryptionKey = Me.generateKey
        Me.encryptionIV = Me.generateIV
    End Sub
 
    Public Sub encryptFile(ByVal input As String, ByVal output As String)
        Try
            inputFile = New FileStream(input, FileMode.Open, FileAccess.Read)
            outputFile = New FileStream(output, FileMode.OpenOrCreate, FileAccess.Write)
            outputFile.SetLength(0)
 
            Dim buffer(4096) As Byte
            Dim bytesProcessed As Long = 0
            Dim fileLength As Long = inputFile.Length
            Dim bytesInCurrentBlock As Integer
            Dim rijandael As New RijndaelManaged
            Dim cryptoStream As CryptoStream = New CryptoStream(outputFile, rijandael.CreateEncryptor(encryptionKey, encryptionIV), CryptoStreamMode.Write)
 
            While bytesProcessed < fileLength
                bytesInCurrentBlock = inputFile.Read(buffer, 0, 4096)
                cryptoStream.Write(buffer, 0, bytesInCurrentBlock)
                bytesProcessed = bytesProcessed + CLng(bytesInCurrentBlock)
            End While
 
            cryptoStream.Close()
            inputFile.Close()
            outputFile.Close()
 
            File.Delete(input)
        Catch ex As Exception
 
        End Try
    End Sub
 
    Public Sub decryptFile(ByVal input As String, ByVal output As String)
        Try
            inputFile = New FileStream(input, FileMode.Open, FileAccess.Read)
            outputFile = New FileStream(output, FileMode.OpenOrCreate, FileAccess.Write)
            outputFile.SetLength(0)
 
            Dim buffer(4096) As Byte
            Dim bytesProcessed As Long = 0
            Dim fileLength As Long = inputFile.Length
            Dim bytesInCurrentBlock As Integer
            Dim rijandael As New RijndaelManaged
            Dim cryptoStream As CryptoStream = New CryptoStream(outputFile, rijandael.CreateDecryptor(encryptionKey, encryptionIV), CryptoStreamMode.Write)
 
            While bytesProcessed < fileLength
                bytesInCurrentBlock = inputFile.Read(buffer, 0, 4096)
                cryptoStream.Write(buffer, 0, bytesInCurrentBlock)
                bytesProcessed = bytesProcessed + CLng(bytesInCurrentBlock)
            End While
 
            cryptoStream.Close()
            inputFile.Close()
            outputFile.Close()
 
            File.Delete(input)
        Catch ex As Exception
 
        End Try
    End Sub
 
    Private Function generateKey() As Byte()
        Try
            Dim data() As Char = Me.password.ToCharArray
            Dim length As Integer = data.GetUpperBound(0)
            Dim hash(length) As Byte
            Dim i As Long = 0
            Dim sha512 As New SHA512Managed
            For i = 0 To data.GetUpperBound(0)
                hash(i) = CByte(Asc(data(i)))
            Next
            Dim result As Byte() = sha512.ComputeHash(hash)
            Dim key(31) As Byte
            For i = 0 To 31 Step 1
                key(i) = result(i)
            Next
            Return key
        Catch ex As Exception
            Return Nothing
        End Try
    End Function
 
    Private Function generateIV() As Byte()
        Try
            Dim data() As Char = Me.password.ToCharArray
            Dim length As Integer = data.GetUpperBound(0)
            Dim hash(length) As Byte
            Dim i As Long = 0
            Dim sha512 As New SHA512Managed
            For i = 0 To data.GetUpperBound(0)
                hash(i) = CByte(Asc(data(i)))
            Next
            Dim result As Byte() = sha512.ComputeHash(hash)
            Dim iv(15) As Byte
            For i = 32 To 47
                iv(i - 32) = result(i)
            Next
            Return iv
        Catch ex As Exception
            Return Nothing
        End Try
    End Function
 
End Class

How to use this?

Below is a small example on how you can use this class. When creating a new instance of the class you then supply the key you want to use. Then you can quickly encrypt/decrypt files. The input file in the encryptFile method is the file you want to encrypt, while the output is the encrypted file you generate. And for decrypting it is obviously the other way around.

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Dim encryption as FileEncryption = New FileEncryption("YOUR KEY GOES HERE")
encryption.encryptFile("input file path", "output file path")
encryption.decryptFile("input file path", "output file path")

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