This invention provides methods and apparatus for protecting data transmitted
using standard compression techniques such as Huffman coding. After input data
is preprocessed (filtered, quantized, etc.), the data is encoded using a Huffman
coder based on Huffman codes or code books which have been scrambled to change
the order of the code books and/or codes from established standard Huffman code
books and/or codes. When the transmitted information is received by a Huffman code
receiver, the received data may be decoded using the scrambled Huffman code book/codes
to obtain the data that was transmitted by the transmitter.
