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|
-- |
-- Module : Crypto.PubKey.Rabin.Types
-- License : BSD-style
-- Maintainer : Carlos Rodriguez-Vega <crodveg@yahoo.es>
-- Stability : experimental
-- Portability : unknown
--
module Crypto.PubKey.Rabin.Types
( Error(..)
, generatePrimes
) where
import Crypto.Number.Basic (numBits)
import Crypto.Number.Prime (generatePrime, findPrimeFromWith)
import Crypto.Random.Types
type PrimeCondition = Integer -> Bool
-- | Error possible during encryption, decryption or signing.
data Error = MessageTooLong -- ^ the message to encrypt is too long
| MessageNotRecognized -- ^ the message decrypted doesn't have a OAEP structure
| InvalidParameters -- ^ some parameters lead to breaking assumptions
deriving (Show, Eq)
-- | Generate primes p & q
generatePrimes :: MonadRandom m
=> Int -- ^ size in bytes
-> PrimeCondition -- ^ condition prime p must satisfy
-> PrimeCondition -- ^ condition prime q must satisfy
-> m (Integer, Integer) -- ^ chosen distinct primes p and q
generatePrimes size pCond qCond =
let pBits = (8*(size `div` 2))
qBits = (8*(size - (size `div` 2)))
in do
p <- generatePrime' pBits pCond
q <- generatePrime' qBits qCond
return (p, q)
where
generatePrime' bits cond = do
pr' <- generatePrime bits
let pr = findPrimeFromWith cond pr'
if numBits pr == bits then return pr
else generatePrime' bits cond
|
