108 lines
3.1 KiB
OCaml
108 lines
3.1 KiB
OCaml
(**************************************************************************)
|
|
(* *)
|
|
(* Copyright (c) 2014 - 2016. *)
|
|
(* Dynamic Ledger Solutions, Inc. <contact@tezos.com> *)
|
|
(* *)
|
|
(* All rights reserved. No warranty, explicit or implicit, provided. *)
|
|
(* *)
|
|
(**************************************************************************)
|
|
|
|
(* Tezos Protocol Implementation - Random number generation *)
|
|
|
|
open Tezos_hash
|
|
|
|
type seed = B of State_hash.t
|
|
type t = T of State_hash.t
|
|
type sequence = S of State_hash.t
|
|
type nonce = MBytes.t
|
|
|
|
let nonce_encoding = Data_encoding.bytes
|
|
|
|
let init = "1234567890123456789012"
|
|
let zero_bytes = MBytes.of_string (String.make Nonce_hash.size '\000')
|
|
|
|
let state_hash_encoding =
|
|
let open Data_encoding in
|
|
conv
|
|
State_hash.to_bytes
|
|
State_hash.of_bytes
|
|
(Fixed.bytes Nonce_hash.size)
|
|
|
|
let seed_encoding =
|
|
let open Data_encoding in
|
|
conv
|
|
(fun (B b) -> b)
|
|
(fun b -> B b)
|
|
state_hash_encoding
|
|
|
|
let empty = B (State_hash.hash_bytes [MBytes.of_string init])
|
|
|
|
let nonce (B state) nonce =
|
|
B (State_hash.hash_bytes ( [State_hash.to_bytes state; nonce] ))
|
|
|
|
let initialize_new (B state) append =
|
|
T (State_hash.hash_bytes
|
|
(State_hash.to_bytes state :: zero_bytes :: append ))
|
|
|
|
let xor_higher_bits i b =
|
|
let higher = MBytes.get_int32 b 0 in
|
|
let r = Int32.logxor higher i in
|
|
let res = MBytes.copy b in
|
|
MBytes.set_int32 res 0 r;
|
|
res
|
|
|
|
let sequence (T state) n =
|
|
State_hash.to_bytes state
|
|
|> xor_higher_bits n
|
|
|> (fun b -> S (State_hash.hash_bytes [b]))
|
|
|
|
let take (S state) =
|
|
let b = State_hash.to_bytes state in
|
|
let h = State_hash.hash_bytes [b] in
|
|
(State_hash.to_bytes h, S h)
|
|
|
|
let take_int32 s bound =
|
|
if Compare.Int32.(bound <= 0l)
|
|
then invalid_arg "Seed_repr.take_int32" (* FIXME *)
|
|
else
|
|
let rec loop s =
|
|
let bytes, s = take s in
|
|
let r = Int32.abs (MBytes.get_int32 bytes 0) in
|
|
let drop_if_over =
|
|
Int32.sub Int32.max_int (Int32.rem Int32.max_int bound) in
|
|
if Compare.Int32.(r >= drop_if_over)
|
|
then loop s
|
|
else
|
|
let v = Int32.rem r bound in
|
|
v, s
|
|
in
|
|
loop s
|
|
|
|
type error += Unexpected_nonce_length
|
|
|
|
let make_nonce nonce =
|
|
if Compare.Int.(MBytes.length nonce <> Constants_repr.nonce_length)
|
|
then error Unexpected_nonce_length
|
|
else ok nonce
|
|
|
|
let hash nonce = Nonce_hash.hash_bytes [nonce]
|
|
|
|
let check_hash nonce hash =
|
|
Compare.Int.(MBytes.length nonce = Constants_repr.nonce_length)
|
|
&& Nonce_hash.equal (Nonce_hash.hash_bytes [nonce]) hash
|
|
|
|
let nonce_hash_key_part = Nonce_hash.to_path
|
|
|
|
let initial_nonce_0 =
|
|
hash
|
|
(MBytes.of_string (String.make Constants_repr.nonce_length '\000'))
|
|
|
|
let initial_seed_0 = B (State_hash.hash_bytes [])
|
|
let initial_seed_1 =
|
|
nonce initial_seed_0
|
|
(MBytes.of_string (String.make Constants_repr.nonce_length '\000'))
|
|
let initial_seed_2 =
|
|
nonce initial_seed_1
|
|
(MBytes.of_string (String.make Constants_repr.nonce_length '\000'))
|
|
|