QPQ-AG/ec_utils
10
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Cleanup and fix type specs

Browse Source
This commit is contained in:
Hans Svensson 2022-10-15 22:24:17 +02:00
parent bf8623e9fc
commit 5a0d41bd62
2 changed files with 21 additions and 20 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
src/ecu_ed25519.erl
View File

@ -11,7 +11,7 @@
-type pt_affine() :: {non_neg_integer(), non_neg_integer()}. %% {X, Y}
-type pt_hom_ext() :: {non_neg_integer(), non_neg_integer(),
non_neg_integer(), non_neg_integer()}. %% {X, Y, Z, T}
-type pt_compressed() :: <<_:32>>. %% Y coord + odd/even X.
-type pt_compressed() :: <<_:256>>. %% Y coord + odd/even X.
-type pt() :: pt_affine() | pt_hom_ext() | pt_compressed().
@ -33,6 +33,8 @@
-define(SUB(A, B), ((A - B + ?P) rem ?P)).
-define(DIV(A, B), f_div(A, B)).
-export_type([pt/0, scalar/0]).
-export([on_curve/1, p/0, n/0, pt_eq/2,
scalar_mul/2, scalar_mul_base/1,
scalar_mul_noclamp/2, scalar_mul_base_noclamp/1,
@ -76,14 +78,14 @@ n() -> ?N.
-define(TWO_POW_255_MINUS_1, 16#7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF).
-spec compress(P :: pt()) -> <<_:32>>.
-spec compress(P :: pt()) -> pt_compressed().
compress(<<_:32/binary>> = P) -> P;
compress({_, _, _, _} = P) -> compress(to_affine(P));
compress({X, Y}) ->
V = (Y band ?TWO_POW_255_MINUS_1) bor ((X band 1) bsl 255),
<<V:256/little>>.
-spec decompress(<<_:32>>) -> pt_hom_ext().
-spec decompress(pt_compressed()) -> pt_hom_ext().
decompress(<<Y0:256/little>>) ->
X0 = Y0 bsr 255,
Y = Y0 band ?TWO_POW_255_MINUS_1,

31
src/ecu_eddsa.erl
View File

@ -16,23 +16,22 @@
%%
%% The keypair is returned as a map with keys 'public' and 'secret'.
%% @end
-spec sign_keypair() -> #{ atom() => binary() }.
-spec sign_keypair() -> #{ public => binary(), secret => binary() }.
sign_keypair() ->
Secret = crypto:strong_rand_bytes(32),
<<Seed:32/bytes, _/binary>> = crypto:hash(sha512, Secret),
<<Seed:32/binary, _/binary>> = crypto:hash(sha512, Secret),
Pub = ecu_ed25519:scalar_mul_base(Seed),
Pub = ecu_ed25519:compress(ecu_ed25519:scalar_mul_base(Seed)),
#{public => Pub, secret => <<Secret:32/binary, Pub:32/binary>>}.
%% @doc sign_seed_keypair/1 computes the signing keypair from a seed.
%%
%% The keypair is returned as a map with keys 'public' and 'secret'.
%% @end
-spec sign_seed_keypair(Seed :: <<_:32>>) -> #{ atom() => binary() }.
-spec sign_seed_keypair(Secret :: <<_:256>>) -> #{ public => binary(), secret => binary() }.
sign_seed_keypair(Secret) ->
<<Seed:32/bytes, _/binary>> = crypto:hash(sha512, Secret),
<<Seed:32/binary, _/binary>> = crypto:hash(sha512, Secret),
Pub = ecu_ed25519:compress(ecu_ed25519:scalar_mul_base(Seed)),
%% Pub = enacl:crypto_ed25519_scalarmult_base(Seed),
#{public => Pub, secret => <<Secret:32/binary, Pub:32/binary>>}.
@ -41,7 +40,7 @@ sign_seed_keypair(Secret) ->
%% Given a message `Msg' and a secret key `SK' the function will sign the
%% message and return a signed message `SM'.
%% @end
-spec sign(Msg :: iodata(), SK :: <<_:32>> | <<_:64>>) -> SM :: binary().
-spec sign(Msg :: iodata(), SK :: <<_:256>> | <<_:512>>) -> SM :: binary().
sign(Msg, SK) ->
BinMsg = iolist_to_binary(Msg),
Sig = sign_detached(Msg, SK),
@ -54,12 +53,12 @@ sign(Msg, SK) ->
%% `{error, failed_verification}' depending on the correctness of the
%% signature.
%% @end
-spec sign_open(SMsg :: binary(), PK :: <<_:32>>) ->
-spec sign_open(SMsg :: binary(), PK :: <<_:256>>) ->
{ok, Msg :: binary()} | {error, failed_verification}.
sign_open(<<Sig:64/binary, BinMsg/binary>>, PK) ->
<<R:32/bytes, Ss:32/bytes>> = Sig,
<<R:32/binary, Ss:32/binary>> = Sig,
Ks0 = crypto:hash(sha512, <<R/bytes, PK/bytes, BinMsg/bytes>>),
Ks0 = crypto:hash(sha512, <<R/binary, PK/binary, BinMsg/binary>>),
Ks = ecu_ed25519:scalar_reduce(Ks0),
LHS = ecu_ed25519:scalar_mul_base_noclamp(Ss),
@ -77,7 +76,7 @@ sign_open(<<Sig:64/binary, BinMsg/binary>>, PK) ->
%% Given a message `Msg' and a secret key `SK' the function will compute the
%% digital signature `Sig'.
%% @end
-spec sign_detached(Msg :: iodata(), SK :: <<_:32>>) -> Sig :: binary().
-spec sign_detached(Msg :: iodata(), SK :: <<_:256>> | <<_:512>>) -> Sig :: binary().
sign_detached(Msg, SK) ->
BinMsg = iolist_to_binary(Msg),
<<Secret:32/binary, _/binary>> = SK,
@ -119,12 +118,12 @@ sign_detached(Msg, SK) ->
%% function computes true iff the `Sig' is valid for `Msg' and `PK'; and,
%% false otherwise.
%% @end
-spec sign_verify_detached(Sig :: <<_:64>>, Msg :: iodata(), PK :: <<_:32>>) -> boolean().
-spec sign_verify_detached(Sig :: <<_:512>>, Msg :: iodata(), PK :: <<_:256>>) -> boolean().
sign_verify_detached(Sig, Msg, PK) ->
BinMsg = iolist_to_binary(Msg),
<<R:32/bytes, Ss:32/bytes>> = Sig,
<<R:32/binary, Ss:32/binary>> = Sig,
Ks0 = crypto:hash(sha512, <<R/bytes, PK/bytes, BinMsg/bytes>>),
Ks0 = crypto:hash(sha512, <<R/binary, PK/binary, BinMsg/binary>>),
Ks = ecu_ed25519:scalar_reduce(Ks0),
LHS = ecu_ed25519:scalar_mul_base_noclamp(Ss),
@ -136,5 +135,5 @@ sign_verify_detached(Sig, Msg, PK) ->
%% Clamp a 32-byte little-endian integer - i.e clear the lowest three bits
%% of the first byte and clear the highest and set the second highest of
%% the last byte (i.e. making it divisible by 8 and
clamp(<<B0:8, B1_30:30/bytes, B31:8>>) ->
<<(B0 band 16#f8):8, B1_30/bytes, ((B31 band 16#7f) bor 16#40):8>>.
clamp(<<B0:8, B1_30:30/binary, B31:8>>) ->
<<(B0 band 16#f8):8, B1_30/binary, ((B31 band 16#7f) bor 16#40):8>>.