(Excel) 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.

Download Excel Class Modules Chilkat Excel Class Modules

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

Dim zip As Chilkat.Zip
Set zip = Chilkat.NewZip

' Open an unencrypted .zip

success = zip.OpenZip("qa_data/zips/test.zip")
If (success <> True) Then
    Debug.Print zip.LastErrorText
    Exit Sub
End If

' Unzip to a temp directory.

numFilesUnzipped = zip.Unzip("qa_output/tmp")
If (numFilesUnzipped < 0) Then
    Debug.Print zip.LastErrorText
    Exit Sub
End If

' Clear the zip object.
Dim success As Boolean
success = 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 <> True) Then
    Debug.Print zip.LastErrorText
    Exit Sub
End If

' Write the .zip and close it.
success = zip.WriteZipAndClose()
If (success <> True) Then
    Debug.Print zip.LastErrorText
    Exit Sub
End If

Debug.Print "Success."