The virus’s genome is already online. You just need the right lab.
Weeeeeellll…yes and no. Smallpox is a BIIIIG genome – not far off in size to the bacterial genome famously resynthesised by Craig Venter et al., a while ago. This means it would be a huge undertaking, cost a LOT of money, and need sophisticated facilities to do it.
Not something your average cave-dwelling fanatic could do, then!
States could do it, however: a well-funded lab in even a country like North Korea could theoretically resynthesise a poxvirus – but why bother?? We have vaccines against smallpox right now; growing poxviruses and vaccinia virus in particular is a well-established biotechnology still.
SO I think this is an artificial concern, to be honest.