add bip39 files from Hans

2022-12-22 00:24:26 -07:00
parent c4f71c8b4d
commit ce4047f795
2 changed files with 151 additions and 0 deletions
@@ -0,0 +1,96 @@
+%%% Author      : Hans Svensson
+%%% Description : Implement BIP0039
+%%% Created     : 12 Jan 2022 by Hans Svensson
+-module(ebip39).
+
+-ifdef(TEST).
+-export([read_wordlist/0, gen_mnemonic/2]).
+-endif.
+
+-export([generate_mnemonic/1,
+         mnemonic_to_seed/2,
+         validate_mnemonic/1]).
+
+-define(WORDLIST, "wordlist_en.txt").
+
+-spec mnemonic_to_seed(Mnemonic :: binary(),
+                       PassPhrase :: iodata()) -> <<_:512>>.
+mnemonic_to_seed(Mnemonic, PassPhrase) ->
+  assert_mnemonic(Mnemonic),
+  {ok, BinSeed} = epbkdf2:pbkdf2(sha512,
+                                 Mnemonic,
+                                 iolist_to_binary(["mnemonic", PassPhrase]),
+                                 2048),
+  BinSeed.
+
+-spec generate_mnemonic(Size :: non_neg_integer()) -> binary().
+generate_mnemonic(Size) ->
+  case Size rem 32 of
+    0 -> gen_mnemonic(Size);
+    _ -> error({bad_mnemonic_size, Size, not_a_multiple_of_32})
+  end.
+
+-spec validate_mnemonic(Mnemonic :: binary()) -> ok | {error, Reason :: atom()}.
+validate_mnemonic(Mnemonic) ->
+  Table = word_table(),
+  Ixs   = [ maps:get(W, Table) || W <- string:lexemes(Mnemonic, " ") ],
+  Size  = length(Ixs) * 11,
+  CSize = Size rem 32,
+  SSize = (Size - CSize) div 8,
+  <<Seed:SSize/bytes, CS:(CSize)>> = << <<Ix:11>> || Ix <- Ixs >>,
+  case crypto:hash(sha256, Seed) of
+    <<CS:(CSize), _/bitstring>> -> ok;
+    _                           -> {error, checksum_error}
+  end.
+
+%% --- Internal functions
+assert_mnemonic(Mnemonic) ->
+  case validate_mnemonic(Mnemonic) of
+    ok -> ok;
+    {error, R} -> error({bad_mnemonic_string, R})
+  end.
+
+
+gen_mnemonic(Size) ->
+  gen_mnemonic(Size, crypto:strong_rand_bytes(Size div 8)).
+
+gen_mnemonic(Size, Seed) ->
+  CSize = Size div 32,
+  <<CS:(CSize), _/bitstring>> = crypto:hash(sha256, Seed),
+  Table  = ix_table(),
+  Words = [ maps:get(G, Table) || <<G:11>> <= <<Seed/bytes, CS:(CSize)>> ],
+  iolist_to_binary(lists:join(<<" ">>, Words)).
+
+word_table() ->
+  Words = read_wordlist(),
+  maps:from_list(lists:zip(Words, lists:seq(0, 2047))).
+
+ix_table() ->
+  Words = read_wordlist(),
+  maps:from_list(lists:zip(lists:seq(0, 2047), Words)).
+
+read_wordlist() ->
+  File = filename:join(code:priv_dir(ebip39), ?WORDLIST),
+  case file:read_file(File) of
+    {ok, BinData} ->
+      read_wordlist(BinData);
+    {error, enotdir} -> %% In escript?
+      try
+        Escript        = escript:script_name(),
+        {ok, Sections} = escript:extract(Escript, []),
+        Archive        = proplists:get_value(archive, Sections),
+        FileName       = filename:join([ebip39, priv, ?WORDLIST]),
+        case zip:extract(Archive, [{file_list, [FileName]}, memory]) of
+          {ok, [{_, BinData}]} -> read_wordlist(BinData);
+          _                    -> error(wordlist_not_found)
+        end
+      catch _E:_R:_S ->
+        error(wordlist_not_found)
+      end
+  end.
+
+read_wordlist(BinData) ->
+  Words = string:lexemes(BinData, "\n"),
+  2048 = length(Words),
+  Words.
+