A method for the human-assisted generation and application of pseudo-random keys for the purpose of encoding and decoding digital watermarks to and from a digitized data stream. A pseudo-random key and key application "envelope" are generated and stored using guideline parameters input by a human engineer interacting with a graphical representation of the digitized data stream. Key "envelope" information is permanently associated with the pseudo-random binary string comprising the key. Key and "envelope" information are then applied in a digital watermark system to the encoding and decoding of digital watermarks. The invention includes improvements to the methods of encoding and decoding digital watermarks. Improvements are: separation of the encoder from the decoder, increased information capacity relative to spread spectrum methods, destruction of content resulting from attempts to erase watermarks, detection of presence of watermarks without ability to access watermark information, multi-channel watermark capability, use of various classes of keys for watermark access control, support for alternative encoding, decoding, or other component algorithms, use of digital notary to authenticate and time stamp watermark certificates.