Invisible Ink

This library includes a set of tools for using zero-width unicode characters to embed human-invisible messages in text.

Watermarking

You can use invisible ink to uniquely identify a piece of text by embedding a UUID:

>>> from invisible_ink import encode_watermark, decode_watermark
>>> encoded_text, uuid = encode_watermark(u'asdf')
>>> print encoded_text
asdf
>>> uuid
UUID('3ca37a37-9c5a-4b9e-a9c0-a50c47c48dba')
>>> decode_watermark(encoded_text)
(u'asdf', UUID('3ca37a37-9c5a-4b9e-a9c0-a50c47c48dba'))

encode_watermark (text, watermark_uuid=None, prepend=False)

Encodes the given text with a watermark string generated from the given uuid. Optionally appends or prepends the watermark string.

Parameters:

• text: Unicode string to which the watermark will be added
• watermark_uuid: uuid.UUID instance to use as the watermark. (uuid.uuid4() will be used to generate one if not provided.)
• prepend: Indicates whether the watermark should be prended to text (defaults to False). If False, the watermark will be appended.

Returns:

A 2-tuple: (encoded_text, watermark_uuid)

decode_watermark (encoded_text)

Decodes the given text, separating out the original text and the watermark uuid.

Paramters:

• encoded_text: Unicode string which potentially includes a watermark

Returns:

A 2-tuple: (text, watermark_uuid). If no watermark is detected, text is the original text and watermark_uuid is None.

Installation

$ pip install invisible-ink