Bcrypt - How many iterations/cost?

Question

I've read some articles saying you should set the cost to be at least 16 (2¹⁶), yet others say 8 or so is fine.

Is there any official standard for how high the cost should be set to?

Answer 1

The cost you should use depends on how fast your hardware (and implementation) is.

Generally speaking a cost of 8 or 10 is fine -- there isn't any noticable delay. It's still a huge level of protection and far better than any home-grown solution using SHAs and salts. Once you upgrade your hardware you could increase the cost to 16. I would say that 16 is a little high at this time, and will probably result in noticeable (and annoying) delays. But if 16 works for you, by all means go for it!