cryptocipher en-/decryption example

cryptocipher-example.hs

-- contrived from the example in the cryptocipher API
module Main where

import Crypto.Cipher

import qualified Data.ByteString as BS
import qualified Data.ByteString.Char8 as CBS

main = do
    let ctx = initAES256 key

    putStrLn "Enter Plaintext (must be multiple of 16)"
    plain <- BS.getLine

    let secret = cbcEncryption ctx iv plain

    let decrypted = cbcDecryption ctx iv secret

    putStrLn "Decrypted: "
    CBS.putStrLn decrypted

-- size must equal that of the block for cipher
-- should be random
iv = BS.replicate 16 3

key = BS.pack [1,2,3,4,5,6,7,8,9,0
              ,1,2,3,4,5,6,7,8,9,0
              ,1,2,3,4,5,6,7,8,9,0
              ,1,2]

initAES256 :: BS.ByteString -> AES256
initAES256 = either (error . show) cipherInit . makeKey

cbcEncryption :: AES256 -> BS.ByteString -> BS.ByteString -> BS.ByteString
cbcEncryption ctx ivRaw plainText = cbcEncrypt ctx iv plainText
  where iv = maybe (error "invalid IV") id $ makeIV ivRaw

cbcDecryption :: AES256 -> BS.ByteString -> BS.ByteString -> BS.ByteString
cbcDecryption ctx ivRaw encrypted = cbcDecrypt ctx iv encrypted
  where iv = maybe (error "invalid IV") id $ makeIV ivRaw