1. A system for authentication of JPEG compressed image data on multi-function equipment comprising: means for receiving said JPEG image data; and a CPU and MEMORY sufficient to enable the decoding steps of: a) deriving a hashing function from a first section of JPEG compressed image data such that any changes subsequently made to said section of data would be reflected in a different hashing function being derived therefrom and producing a first integrity checking number from said derived hashing function; b) identifying a second section of data and decoding therefrom an embedded signature string; c) decrypted said signature string to recover a second integrity checking number; d) comparing said recovered second integrity checking number with said first derived integrity checking number and, if the two numbers match, then authenticating the data; e) repeating steps A-D for each successive data sections until the very last data section is reached; and f) at the very last data section, equating said last section of data as said second section and performing steps A-D.