Abstract: 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.

Abstract: A digitally signed message, protected with a chain of certificates from the sender's immediate certifier up through an ultimate certifier, is transmitted to a recipient together with the entire certificate chain. The entire certificate chain is stored in a single signer file accessible by the sender. Drag-and-drop gestures of a graphical user interface are used by the sender to sign and certify the message, and an icon is provided on the recipient's display to initiate verification.