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{-# LANGUAGE GeneralizedNewtypeDeriving, MultiParamTypeClasses #-}
{- Copyright 2016 Joey Hess <id@joeyh.name>
-
- Licensed under the GNU AGPL version 3 or higher.
-}
module Cost (
module Cost,
module Types.Cost
) where
import Types.Cost
-- | Cost in seconds, with the type of hardware needed.
totalCost :: Cost op -> (Seconds, [UsingHardware])
totalCost (CPUCost s) = (s, [UsingCPU])
totalCost (GPUCost s) = (s, [UsingGPU])
totalCost (CombinedCost a b) =
let (s1, h1) = totalCost a
(s2, h2) = totalCost b
in (s1+s2, h1++h2)
raiseCostPower :: Cost c -> Entropy e -> Cost c
raiseCostPower c (Entropy e) = adjustCost c (* 2^e)
adjustCost :: Cost c -> (Seconds -> Seconds) -> Cost c
adjustCost (CPUCost s) f = CPUCost (f s)
adjustCost (GPUCost s) f = GPUCost (f s)
adjustCost (CombinedCost a b) f = CombinedCost (adjustCost a f) (adjustCost b f)
castCost :: Cost a -> Cost b
castCost (CPUCost s) = CPUCost s
castCost (GPUCost s) = GPUCost s
castCost (CombinedCost a b) = CombinedCost (castCost a) (castCost b)
-- | CostCalc for a brute force linear search through an entropy space
-- in which each step entails paying a cost.
--
-- On average, the solution will be found half way through.
-- This is equivilant to one bit less of entropy.
bruteForceLinearSearch :: Cost step -> CostCalc BruteForceOp t
bruteForceLinearSearch stepcost e =
castCost stepcost `raiseCostPower` reduceEntropy e 1
-- | Estimate of cost of a brute force attack.
estimateBruteforceOf :: Bruteforceable t a => t -> Entropy a -> Cost BruteForceOp
estimateBruteforceOf t e = getBruteCostCalc t e
data DataCenterPrice = DataCenterPrice
{ instanceCpuCores :: Integer
, instanceCostPerHour :: Cents
}
-- August 2016 spot pricing: 36 CPU core c4.8xlarge at 33c/hour
spotAWS :: DataCenterPrice
spotAWS = DataCenterPrice
{ instanceCpuCores = 36
, instanceCostPerHour = Cents 33
}
-- | Estimate of cost of brute force attack using a datacenter.
--
-- Note that this assumes that CPU cores and GPU cores are of equal number,
-- which is unlikely to be the case; typically there will be many more
-- cores than GPUs. So, this underestimates the price to brute force
-- operations which run faster on GPUs.
estimateAttack :: DataCenterPrice -> Cost BruteForceOp -> Dollars
estimateAttack dc opcost = centsToDollars $ costcents
where
(Seconds cpuseconds) = fst (totalCost opcost)
cpuyears = cpuseconds `div` (60*60*24*365)
costpercpuyear = Cents $
fromIntegral (instanceCostPerHour dc) * 24 * 365
`div` instanceCpuCores dc
costcents = Cents cpuyears * costpercpuyear
newtype Cents = Cents Integer
deriving (Num, Integral, Enum, Real, Ord, Eq, Show)
newtype Dollars = Dollars Integer
deriving (Num, Integral, Enum, Real, Ord, Eq, Show)
centsToDollars :: Cents -> Dollars
centsToDollars (Cents c) = Dollars (c `div` 100)
|
