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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 (findPrimeFromWith, generatePrime)
import Crypto.Random.Types
type PrimeCondition = Integer -> Bool
-- | Error possible during encryption, decryption or signing.
data Error
= -- | the message to encrypt is too long
MessageTooLong
| -- | the message decrypted doesn't have a OAEP structure
MessageNotRecognized
| -- | some parameters lead to breaking assumptions
InvalidParameters
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
|
