A method and apparatus for generating and authenticating documents having
stored electrostatic pattern information provides security with respect
to the authenticity of documents. A liquid medium including a plurality
of electrostatic monopoles is applied to the surface of a document, which
embeds a permanent electrostatic pattern in the document. The pattern is
then readable by an electrostatic scanner. The monopoles may be
associated with differing colors, including black and white, may be
transparent or have a neutral color. The patterns may embed data,
certificates or shapes. The monopoles may provide a watermark or visible
image. The apparatus may be a pen or printer, and may include multiple
selectable vessels containing ink and/or electrostatic liquid medium of
one or both charge states. Visible features of the document can be
compared with the detected pattern, or the pattern may be compared to a
database or decrypted with a key.