 Subsetting reduces the value of copying, as subsetted fonts will typically omit more than half of the characters.Other copy protection measures used are encryption and a list of "trusted roots" at the source end, and a proprietary decrypting library at the receiving end.If the embedded font is not available to the web page for any reason (missing font file, wrong keys in the file, non-support by the web browser), then the second-choice font specification is used, ensuring that the page should be readable even without the intended font.