(PowerBuilder) Streaming Encryption

Encrypt and decrypt using a stream.

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

integer li_rc
oleobject loo_Crypt
string ls_IvHex
string ls_KeyHex
string ls_PlainText
oleobject loo_Stream
oleobject loo_EStrings
oleobject loo_Task
integer li_Success
string ls_CipherText
integer i
integer n

// This example assumes the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

loo_Crypt = create oleobject
li_rc = loo_Crypt.ConnectToNewObject("Chilkat_9_5_0.Crypt2")
if li_rc < 0 then
    destroy loo_Crypt
    MessageBox("Error","Connecting to COM object failed")
    return
end if

// Setup encryption using the chacha20 algorithm...
loo_Crypt.CryptAlgorithm = "chacha20"
loo_Crypt.KeyLength = 256
loo_Crypt.EncodingMode = "hex"
ls_IvHex = "000000000000000000000002"
loo_Crypt.SetEncodedIV(ls_IvHex,"hex")
loo_Crypt.InitialCount = 42
ls_KeyHex = "1c9240a5eb55d38af333888604f6b5f0473917c1402b80099dca5cbc207075c0"
loo_Crypt.SetEncodedKey(ls_KeyHex,"hex")

ls_PlainText = "The quick brown fox jumped over the lazy dog.~r~n"

loo_Stream = create oleobject
li_rc = loo_Stream.ConnectToNewObject("Chilkat_9_5_0.Stream")

// We'll save the encrypted output in eStrings to demonstrate streaming decryption next.
loo_EStrings = create oleobject
li_rc = loo_EStrings.ConnectToNewObject("Chilkat_9_5_0.StringArray")

// Start a background task that will encrypt a stream.
loo_Task = loo_Crypt.EncryptStreamAsync(loo_Stream)
li_Success = loo_Task.Run()

// Write plainText to the stream, and read chacha20 encrypted text..

for i = 1 to 10
    // Note: An encryption algorithm's block size will cause buffering,
    // and therefore not every loop iteration will produce output.
    li_Success = loo_Stream.WriteString(ls_PlainText)
    if loo_Stream.DataAvailable = 1 then
        ls_CipherText = loo_Stream.ReadBytesENC("hex")
        Write-Debug ls_CipherText
        li_Success = loo_EStrings.Append(ls_CipherText)
    end if

next

// Tell the background task that the stream has ended.
li_Success = loo_Stream.WriteClose()

// Let's make sure the background task finished.
// It should already be the case that the task is finished.
do while (loo_Task.Finished <> 1)
    loo_Task.SleepMs(20)
loop

// Get any remaining data available from the stream.
if loo_Stream.DataAvailable = 1 then
    ls_CipherText = loo_Stream.ReadBytesENC("hex")
    Write-Debug ls_CipherText
    li_Success = loo_EStrings.Append(ls_CipherText)
end if

if loo_Task.TaskSuccess <> 1 then
    Write-Debug "async encryption failed:"
    Write-Debug loo_Task.ResultErrorText
    li_Success = 0
end if

destroy loo_Task

Write-Debug "-- encrypt finished --"

// Now decrypt to return the original.

// Reset the stream object so it can be used again.
loo_Stream.Reset()

// Start a background task that will decrypt a stream.
loo_Task = loo_Crypt.DecryptStreamAsync(loo_Stream)
li_Success = loo_Task.Run()

n = loo_EStrings.Count
for i = 0 to n - 1
    li_Success = loo_Stream.WriteBytesENC(loo_EStrings.GetString(i),"hex")
    if loo_Stream.DataAvailable = 1 then
        ls_PlainText = loo_Stream.ReadString()
        Write-Debug ls_PlainText
    end if

next

// Tell the background task that the stream has ended.
li_Success = loo_Stream.WriteClose()

// Let's make sure the background task finished.
// It should already be the case that the task is finished.
do while (loo_Task.Finished <> 1)
    loo_Task.SleepMs(20)
loop

// Get any remaining data available from the stream.
if loo_Stream.DataAvailable = 1 then
    ls_PlainText = loo_Stream.ReadString()
    Write-Debug ls_PlainText
end if

if loo_Task.TaskSuccess <> 1 then
    Write-Debug "async decryption failed:"
    Write-Debug loo_Task.ResultErrorText
    li_Success = 0
end if

destroy loo_Task

Write-Debug "-- decrypt finished --"


destroy loo_Crypt
destroy loo_Stream
destroy loo_EStrings