Computer-implemented methods, systems, and computer program products for document authentication and identification using encoding and decoding are provided. A method includes receiving a digitized document and comparing the digitized document to a set of markers to determine whether the digitized document is an encoded document with one or more characters replaced. In response to determining that the digitized document is encoded, information is extracted from the set of markers using a decoder according to an encoding strategy. The extracted information and the set of markers are compared with data stored in encoding history to authenticate and identify the received digitized document. Markers in the encoded document may be hidden in plain sight, such that the encoding is not readily apparent to a casual observer.