Method for Embedding Messages into Documents Using Distance Fields

A method for embedding a message into a document, comprising:

• representing at least part of a document as a distance field including distance values;
• representing a symbol in a message to be embedded in the document as a modification of a subset of the values in the distance field;
• and
• modifying the subset of the values in the distance field according to the modification to produce a modified document, wherein the symbol in the message is embedded in the modified document.

A method for embedding a message into a document, comprising:

• representing a glyph in a document as a distance field including distance values;
• mapping the distance values in the distance field to a set of density values;
• representing a symbol in a message to be embedded in the document as modification of a subset of the set of density values;
• and
• modifying the subset of the set of density values according to the modification to produce a modified document, wherein the symbol in the message is embedded in the modified document.