(VB.NET) Streaming Compression --> Streaming Encryption

Demonstrate how to feed a compression stream into an encryption stream. This example does the following:

Data File --> Compress --> Encrypt --> Application Reads

Chilkat .NET Downloads Chilkat .NET Assemblies Chilkat for .NET Core Chilkat for Mono

'  This requires the Chilkat API to have been previously unlocked.
'  See Global Unlock Sample for sample code.

Dim success As Boolean

'  Initialize the compression object.
Dim compress As New Chilkat.Compression
compress.Algorithm = "deflate"

'  Initialize the encryption object.
Dim crypt As New Chilkat.Crypt2
crypt.CryptAlgorithm = "chacha20"
crypt.KeyLength = 256
crypt.EncodingMode = "hex"
Dim ivHex As String = "000000000000000000000002"
crypt.SetEncodedIV(ivHex,"hex")
crypt.InitialCount = 42
Dim keyHex As String = "1c9240a5eb55d38af333888604f6b5f0473917c1402b80099dca5cbc207075c0"
crypt.SetEncodedKey(keyHex,"hex")

'  Setup the streams.
'  streamC is for compression
Dim streamC As New Chilkat.Stream
'  streamE is for encryption
Dim streamE As New Chilkat.Stream

'  The source for the compressor is a file.
streamC.SourceFile = "qa_data/hamlet.xml"
'  The source for the encryptor is the output of the compressor stream.
success = streamE.SetSourceStream(streamC)

'  Our application will be reading the output of streamE.
'  Start the compression and encryption streams in background threads..
Dim taskC As Chilkat.Task = compress.CompressStreamAsync(streamC)
Dim taskE As Chilkat.Task = crypt.EncryptStreamAsync(streamE)
success = taskC.Run()
success = taskE.Run()

'  Read the compressed and encrypted bytes.
Dim outData As New Chilkat.BinData
While (streamE.EndOfStream <> True)
    If (streamE.DataAvailable = True) Then
        success = streamE.ReadBd(outData)
    End If

End While

'  Let's make sure the background task finished.
'  It should already be the case that the task is finished.
While ((taskE.Finished <> True) Or (taskC.Finished <> True))
    taskE.SleepMs(20)
End While


'  Get any remaining data that needs to be flushed.
If (streamE.DataAvailable = True) Then
    success = streamE.ReadBd(outData)
End If


'  Double-check for success..
If (taskE.TaskSuccess <> True) Then
    Debug.WriteLine("async encryption failed:")
    Debug.WriteLine(taskE.ResultErrorText)
    success = False
End If


'  Double-check for success..
If (taskC.TaskSuccess <> True) Then
    Debug.WriteLine("async compression failed:")
    Debug.WriteLine(taskC.ResultErrorText)
    success = False
End If





'  Save the compressed/encrypted data to a file.
outData.WriteFile("qa_output/compressedEncrypted.dat")

Debug.WriteLine("The async compress/encrypt was successful.")


'  Let's decrypt and decompress to further verify...
success = crypt.DecryptBd(outData)
success = compress.DecompressBd(outData)

'  outData should contain the original data..
success = outData.WriteFile("qa_output/original_hamlet.xml")