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(Xojo Plugin) Streaming Compression --> Streaming EncryptionDemonstrate how to feed a compression stream into an encryption stream. This example does the following: Data File --> Compress --> Encrypt --> Application Reads
// 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 ivHex = "000000000000000000000002" crypt.SetEncodedIV ivHex,"hex" crypt.InitialCount = 42 Dim keyHex As String keyHex = "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 taskC = compress.CompressStreamAsync(streamC) Dim taskE As Chilkat.Task taskE = 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 Wend // 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 Wend // 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 System.DebugLog("async encryption failed:") System.DebugLog(taskE.ResultErrorText) success = False End If // Double-check for success.. If (taskC.TaskSuccess <> True) Then System.DebugLog("async compression failed:") System.DebugLog(taskC.ResultErrorText) success = False End If // Save the compressed/encrypted data to a file. success = outData.WriteFile("qa_output/compressedEncrypted.dat") System.DebugLog("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") |
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