(PowerShell) Encrypt Already Existing Zip

To encrypt an already existing non-encrypted .zip, the application must open the .zip, set the encryption related properties, and then re-write.

Chilkat .NET Downloads Chilkat .NET Assemblies

Add-Type -Path "C:\chilkat\ChilkatDotNet47-9.5.0-x64\ChilkatDotNet47.dll"

# This requires the Chilkat Zip API to have been previously unlocked.
# See Unlock Chilkat Zip for sample code.

$zip = New-Object Chilkat.Zip

# Open an unencrypted .zip
$success = $zip.OpenZip("qa_data/zips/test.zip")
if ($success -ne $true) {
    $($zip.LastErrorText)
    exit
}

# Unzip to a temp directory.
$numFilesUnzipped = $zip.Unzip("qa_output/tmp")
if ($numFilesUnzipped -lt 0) {
    $($zip.LastErrorText)
    exit
}

# Clear the zip object.
$zip.NewZip("qa_output/aesTest.zip")

# Indicate that 128-bit AES encryption is to be used when writing the .zip
$zip.Encryption = 4
$zip.EncryptKeyLength = 128

# Set the password.
$zip.EncryptPassword = "secret"

# Append the files.
$zip.AppendFromDir = "qa_output/tmp"
$success = $zip.AppendFiles("*.*",$true)
if ($success -ne $true) {
    $($zip.LastErrorText)
    exit
}

# Write the .zip and close it.
$success = $zip.WriteZipAndClose()
if ($success -ne $true) {
    $($zip.LastErrorText)
    exit
}

$("Success.")