Systems and methods for payload encoding and decoding are disclosed. An example method to decode audio data includes receiving audio data having protected information embedded in the audio data; receiving a license file containing a first portion of a set of information required to access the protected information embedded in the audio data; processing the license file to obtain at least one of decoding information, message codes, a decoding algorithm or diagnostic information; producing a stream of symbol values for each code symbol included in the received audio signal; accumulating the stream of symbol values in a storage device; detecting the presence of an encoded message; outputting the detected message.