Examples: IsEncrypted property (NotesItem - LotusScript®)
This script encrypts the Body item in a document. Any other items on the document remain unencrypted.
Dim doc As NotesDocument
Dim item As NotesItem
'...set value of doc...
Set item = doc.GetFirstItem( "Body" )
item.IsEncrypted = True
Call doc.Encrypt
Call doc.Save( False, True )