Remove Zip Encryption

Opens an encrypted zip archive and rewrites it with no encrypton.

Download: Chilkat .NET Assemblies

Dim zip As New Chilkat.Zip()

Dim success As Boolean

'  Any string unlocks the component for the 1st 30-days.
success = zip.UnlockComponent("Anything for 30-day trial")
If (success <> true) Then
    MsgBox(zip.LastErrorText)
    Exit Sub
End If


'  An encrypted .zip may be "opened" without providing a
'  password.  However, the contents cannot be unzipped
'  without setting the DecryptPassword property.
success = zip.OpenZip("myEncrypted.zip")
If (success <> true) Then
    MsgBox(zip.LastErrorText)
    Exit Sub
End If


'  Set the DecryptPassword property:
zip.DecryptPassword = "myPassword"

'  Indicate that when the zip is to be written again,
'  it should be neither AES encrypted, or password-protected
'  (i.e. older Zip 2.0 encryption)
zip.Encryption = 0
zip.PasswordProtect = false

'  Set the filename of the new unencrypted .zip to be written:
zip.FileName = "unencrypted.zip"

'  Write the unencrypted .zip
'  What happens during WriteZipAndClose?  --
'  The encrypted entries from myEncrypted.zip are streamed in,
'  decrypted, and then written out directly into unencrypted.zip
'  In other words, internally the component is smart enough
'  to stream the data from the existing .zip to the new .zip
'  automatically, decrypting in the process..
success = zip.WriteZipAndClose()
If (success <> true) Then
    MsgBox(zip.LastErrorText)
    Exit Sub
End If


MsgBox("OK!")