[Mono-dev] DES problem

[Arnhoffer Károly]

Hi,

I've got a service application which uses encrypted data over network. My decrypting function gives different results with the same inputs on Mono which does not occour on .NET. The other mighty thing is that when I grab this function out of the service and test it in itself this problem does not happen again. What is wrong here?

My function looks as follows (test version):

    Friend Function DecryptDataDES(ByVal tbytaData As Byte(), ByVal tbytaDESKey As Byte(), ByVal tbytaDESIV As Byte(), ByRef tbytaDecryptedData As Byte()) As Boolean
        Dim lobjMemStream As MemoryStream
        Dim lobjCryptoStream As CryptoStream
        Dim lbytaDESKey As Byte()
        Dim lbytaDESIV As Byte()
        Try
            'console.writeline()
            ReDim lbytaDESKey(tbytaDESKey.Length - 1)
            ReDim lbytaDESIV(tbytaDESIV.Length - 1)
            tbytaDESKey.CopyTo(lbytaDESKey, 0)
            tbytaDESIV.CopyTo(lbytaDESIV, 0)

            Console.WriteLine("tbytaData: " & Convert.ToBase64String(tbytaData))
            Console.WriteLine("lbytaDESKey: " & Convert.ToBase64String(lbytaDESKey))
            Console.WriteLine("lbytaDESIV: " & Convert.ToBase64String(lbytaDESIV))

            'teszt
            If Not InitTripleDESCSP(lbytaDESKey, lbytaDESIV) Then
                'ak20050721: ha nem kényszerítjük ki az újrainicializálást, akkor linux/mono-n ugyanolyan bemenet mellett eltérő eredményt fog
                'adni a DecryptDataDES függvény. Emiatt InitTripleDESCSP(lbytaDESKey, lbytaDESIV) helyett InitTripleDESCSP(lbytaDESKey, lbytaDESIV, True)
                'szerepel a hívásban
                'console.writeline("Forced reinit...")
                'If Not InitTripleDESCSP(lbytaDESKey, lbytaDESIV, True) Then
                'mobjApp.Errors.Add(mstrResName, CommErrEnum.CantDecryptDataDES, , , "InitTripleDESCSP").Raise()
                Console.WriteLine("InitTripleDESCSP failed")
            End If

            Console.WriteLine("lbytaDESKey: " & Convert.ToBase64String(lbytaDESKey))
            Console.WriteLine("lbytaDESIV: " & Convert.ToBase64String(lbytaDESIV))

            lobjMemStream = New MemoryStream()
            lobjCryptoStream = New CryptoStream(lobjMemStream, mobjDecryptTransform, CryptoStreamMode.Write)
            'Írás közben dekódolja az adatot
            lobjCryptoStream.Write(tbytaData, 0, tbytaData.Length)
            lobjCryptoStream.FlushFinalBlock()
            lobjCryptoStream.Close()    'e nélkül nem működik!!!
            'Kiolvassuk a dekódolt adatot
            tbytaDecryptedData = lobjMemStream.ToArray()

            Console.WriteLine("tbytaDecryptedData: " & Convert.ToBase64String(tbytaDecryptedData))

            Return True
        Catch ex As Exception
            Console.WriteLine("DecryptDataDES failed")
        Finally
            Try
                If Not lobjMemStream Is Nothing Then lobjMemStream.Close()
                If Not lobjCryptoStream Is Nothing Then lobjCryptoStream.Close()
            Catch
            End Try
        End Try
    End Function

Thanks!

Károly