3 ms·

Unless you run C2 on top of C1.

• tedunangst 15y ago
  bcrypt doesn't work like that. The outline is: work * costfactor finish The finish step is irreversible, so you can't unwind it and add more work later. In practice though, even low cost factors for bcrypt are tons more work than MD5 or SHA. It's not a big deal.
  • palish 15y ago
    He didn't say "unwind it". He said "on top of it". bcrypt( bcrypt( "foo", c1 ), c2 )
  • tzs 15y ago
    I think what he means by run C2 on top of C1 is something like this. Let b(k,w) mean bcrypt with work factor w on input k. So, initially, you are storing b(pass,C1). Running C2 on top of C1 would mean replacing that with b(b(pass,C1),C2). Later, when you want even more work, another layer could be added: b(b(b(pass,C1),C2),C3) and so on.
    • tedunangst 15y ago
      ugh, no thank you.