Any website offering a “portable” AutoCAD 2013 64-bit is almost certainly offering a cracked, modified, or pirated copy .
Would you like help finding a legal lightweight CAD alternative for a USB drive instead? Download AutoCAD 2013 Portable 64 Bit
If you need real AutoCAD 2013 functionality on the go, your only legitimate option is an (current version) or an older perpetual license from a reseller — neither is portable. Any website offering a “portable” AutoCAD 2013 64-bit