perl -le"print unpack'H*', pack'B*', 
unpack('B*',pack'H*','DA39A3EE5E6B4B0D3255BFEF95601890AFD80709') & 
unpack('B*',pack'H*','FFFF804020100804020100804020100804000102')"

da39804000000804020100800020100004000100