Invalid mathematical (cryptographic) symbols rendered in some PDF's (needs symbol.ttf)
Some cryptographic symbols will not be correctly rendered in some PDF's. For example in the official AES specification (XOR and Multiply). These two symbols will be replaced with one invalid symbol.
A Workaround is, to copy the symbol.ttf from a Windows installation and add it to the local fonts collection. Seems these symbols are not supported in the default font collection from poppler.
I have attached the source PDF (NIST.FIPS.197.pdf) and the screenshots from the frontend viewer Okular which uses poppler as backend for the rendering of PDF's.
Rendering with the default font collection:
(Screenshots from page 7 from the original document.)
Have already reported this behavior first on the openSUSE's bug tracker.