Method, apparatuses and computer program product for verifying the signatures of signed files and for conversion of unsigned files

摘要

When a receiver (134) obtains an unsigned file (130) from a data source (106), a converter (146) transforms the unsigned file which is then stored in a memory (140). A program component (148) includes a mark in the transformed file which is then sent to a network (102) by the receiver (150). The receiver (134) may obtain a file (152) having a secret signature component (118) from the data source (104). A signature verifier (144) verifies the authenticity of the signature. The receiver (150) sends the file to the network if the signature is authentic.