From ceafc8ccb7d3cc9cd95b1aa5f0fb51de65dbd3d8 Mon Sep 17 00:00:00 2001
From: Umgeher Torgersen <me@umgeher.org>
Date: Sun, 8 Jan 2023 16:52:51 +0000
Subject: [PATCH] new fns: hex_encode and sha256

---
 src/utools.erl | 78 +++++++++++++++++++++++++++++---------------------
 1 file changed, 45 insertions(+), 33 deletions(-)

diff --git a/src/utools.erl b/src/utools.erl
index 9a76ee2..9665650 100644
--- a/src/utools.erl
+++ b/src/utools.erl
@@ -2,66 +2,75 @@
 
 -export([b32_decode/1]).
 -export([b32_encode/1]).
+-export([hex_encode/1]).
 -export([hotp/2]).
 -export([rand_bytes/0, rand_bytes/1]).
 -export([rand_chars/1]).
 -export([rand_hash/0]).
+-export([sha256/1]).
 -export([totp/1, totp/2]).
 -export([totp_check/2]).
 -export([totp_generate/0]).
 
 b32_decode({<<V, "======">>, Bits}) ->
-    <<Bits/bits, (b32_std_dec(V) bsr 2):3>>;
+  <<Bits/bits, (b32_std_dec(V) bsr 2):3>>;
 b32_decode({<<V, "====">>, Bits}) ->
-    <<Bits/bits, (b32_std_dec(V) bsr 4):1>>;
+  <<Bits/bits, (b32_std_dec(V) bsr 4):1>>;
 b32_decode({<<V, "===">>, Bits}) ->
-    <<Bits/bits, (b32_std_dec(V) bsr 1):4>>;
+  <<Bits/bits, (b32_std_dec(V) bsr 1):4>>;
 b32_decode({<<V, "=">>, Bits}) ->
-    <<Bits/bits, (b32_std_dec(V) bsr 3):2>>;
+  <<Bits/bits, (b32_std_dec(V) bsr 3):2>>;
 b32_decode({<<V, R/binary>>, Bits}) ->
-    b32_decode({R, <<Bits/bits, (b32_std_dec(V)):5>>});
+  b32_decode({R, <<Bits/bits, (b32_std_dec(V)):5>>});
 b32_decode({<<>>, Bits}) ->
-    Bits;
+  Bits;
 b32_decode(V) when is_list(V) ->
-    b32_decode(list_to_binary(V));
+  b32_decode(list_to_binary(V));
 b32_decode(V) when is_binary(V) ->
-    b32_decode({V, <<>>}).
+  b32_decode({V, <<>>}).
 
 b32_encode({body, V}) ->
-    O = 5 * (byte_size(V) div 5),
-    <<Body:O/binary, R/binary>> = V,
-    {<< <<(b32_std_enc(X))>> || <<X:5>> <= Body>>, R};
+  O = 5 * (byte_size(V) div 5),
+  <<Body:O/binary, R/binary>> = V,
+  {<< <<(b32_std_enc(X))>> || <<X:5>> <= Body>>, R};
 b32_encode({rest, V}) ->
-    O = 5 * (bit_size(V) div 5),
-    <<Body:O/bits, Rest/bits>> = V,
-    B0 = << <<(b32_std_enc(X))>> || <<X:5>> <= Body>>,
-    {B1, Pad} = case Rest of
-		    <<I:3>> -> {<<(b32_std_enc(I bsl 2))>>, 6};
-		    <<I:1>> -> {<<(b32_std_enc(I bsl 4))>>, 4};
-		    <<I:4>> -> {<<(b32_std_enc(I bsl 1))>>, 3};
-		    <<I:2>> -> {<<(b32_std_enc(I bsl 3))>>, 1};
-		    <<>> -> {<<>>, 0}
-		end,
-    {<<B0/binary, B1/binary>>, Pad};
+  O = 5 * (bit_size(V) div 5),
+  <<Body:O/bits, Rest/bits>> = V,
+  B0 = << <<(b32_std_enc(X))>> || <<X:5>> <= Body>>,
+  {B1, Pad} = case Rest of
+                <<I:3>> -> {<<(b32_std_enc(I bsl 2))>>, 6};
+                <<I:1>> -> {<<(b32_std_enc(I bsl 4))>>, 4};
+                <<I:4>> -> {<<(b32_std_enc(I bsl 1))>>, 3};
+                <<I:2>> -> {<<(b32_std_enc(I bsl 3))>>, 1};
+                <<>> -> {<<>>, 0}
+              end,
+  {<<B0/binary, B1/binary>>, Pad};
 b32_encode(V) when is_list(V) ->
-    b32_encode(list_to_binary(V));
+  b32_encode(list_to_binary(V));
 b32_encode(V) when is_binary(V) ->
-    {EB, _R} = b32_encode({body, V}),
-    {ER, P} = b32_encode({rest, V}),
-    Padding = list_to_binary(lists:duplicate(P, $=)),
-    <<EB/binary, ER/binary, Padding/binary>>.
+  {EB, _R} = b32_encode({body, V}),
+  {ER, P} = b32_encode({rest, V}),
+  Padding = list_to_binary(lists:duplicate(P, $=)),
+  <<EB/binary, ER/binary, Padding/binary>>.
 
 b32_std_dec(I) when I >= $2 andalso I =< $7 -> 
-    I - 24;
+  I - 24;
 b32_std_dec(I) when I >= $a andalso I =< $z -> 
-    I - $a;
+  I - $a;
 b32_std_dec(I) when I >= $A andalso I =< $Z -> 
-    I - $A.
+  I - $A.
 
 b32_std_enc(I) when is_integer(I) andalso I >= 26 andalso I =< 31 ->
-    I + 24;
+  I + 24;
 b32_std_enc(I) when is_integer(I) andalso I >= 0 andalso I =< 25 ->
-    I + $a.
+  I + $a.
+
+hex_encode(<<X:128/big-unsigned-integer>>) ->
+  binary:list_to_bin(lists:flatten(io_lib:format("~32.16.0b", [X])));
+hex_encode(<<X:160/big-unsigned-integer>>) ->
+  binary:list_to_bin(lists:flatten(io_lib:format("~40.16.0b", [X])));
+hex_encode(<<X:256/big-unsigned-integer>>) ->
+  binary:list_to_bin(lists:flatten(io_lib:format("~64.16.0b", [X]))).
 
 hotp(Token, Time) ->
   K = b32_decode(Token),
@@ -92,7 +101,10 @@ rand_chars(Size) when Size > 0 ->
 
 rand_hash() ->
   {ok, R} = rand_chars(64),
-  {ok, binary:encode_hex(crypto:hash(sha256, <<"utools:rand_hash(", R/binary, ")">>))}.
+  {ok, sha256(<<"utools:rand_hash(", R/binary, ")">>)}.
+
+sha256(<<Data/binary>>) ->
+  hex_encode(crypto:hash(sha256, Data)).
 
 totp(<<Secret/binary>>) ->
   totp(Secret, erlang:timestamp()).