anchor.diff:  let rootBig (n: BigInteger) (A: BigInteger) : BigInteger =
       let rec f x tries =
           match tries with
  -        | 10000 -> x
  -        | _     -> let m = n - (BigInteger 1)
  -                   let x' = (m*x + A/(BigInteger.Pow (x, (int m)))) / n
  -                   match abs(x' - x) with
  -                   | t when t < (BigInteger 2) -> x'
  -                   | _ -> f x' (tries+1)
  +        | 100000 -> x
  +        | _      -> let m = n - (BigInteger 1)
  +                    let x' = (m*x + A/(BigInteger.Pow (x, (int m)))) / n
  +                    match abs(x' - x) with
  +                    | t when t < (BigInteger 2) -> x'
  +                    | _ -> f x' (tries+1)
       f (A / n) 0
   
   (* DSA *)
  
positive.code:     
  let genPrime (bits: int) : BigInteger =
      let rec loop (n: int) (r: Random): BigInteger =
          match n > 1000 with
          | true -> BigInteger 0
          | _    -> let g = genBigInt r bits
                    if isProbPrime g then g else loop (n+1) r
  
negative.code: 
  (* RSA *)
  
  let rec genRSAKeys (r: Random) (bits: int) : ((BigInteger * BigInteger) * (BigInteger * BigInteger)) =
      let e, one, zero = (BigInteger 3), (BigInteger 0), (BigInteger 1)
      let p, q = genPrime bits, genPrime bits
      let p', q' = p - one, q - one
      match p = q || p' % e = zero || q' % e = zero with
      | true -> genRSAKeys r bits
      | _     -> let n = p * q
                 let et = p' * q'
                 let d = modInvBig e et
                 match d with
                 | Some v -> ((e, n), (v, n))
                 | _      -> genRSAKeys r bits
  
  let genRSAKeysSample =
      let p = "ffffffffffffffffc90fdaa22168c234c4c6628b80dc1cd129024e088a67cc74020bbea63b139b22514a08798e3404ddef9519b3cd3a431b302b0a6df25f14374fe1356d6d51c245e485b576625e7ec6f44c42e9a637ed6b0bff5cb6f406b7edee386bfb5a899fa5ae9f24117c4b1fe649286651ece45b3dc2007cb8a163bf0598da48361c55d39a69163fa8fd24cf5f83655d23dca3ad961c62f356208552bb9ed529077096966d670c354e4abc9804f1746c08ca237327ffffffffffffffff" |> hexToBigInt
  