From 6f4a0c2521a2f20dec9b2db76e8bb77dbbfb743b Mon Sep 17 00:00:00 2001
From: Ole Andre Birkedal <birkedal85@gmail.com>
Date: Sat, 8 Jun 2019 18:19:44 +0200
Subject: [PATCH] Added bindings for crypto_sign_seed_keypair in libsodium

---
 c_src/enacl_nif.c | 30 ++++++++++++++++++++++++++++++
 src/enacl.erl     | 17 +++++++++++++++++
 src/enacl_nif.erl |  4 ++++
 3 files changed, 51 insertions(+)

diff --git a/c_src/enacl_nif.c b/c_src/enacl_nif.c
index 1497215..dbc3393 100644
--- a/c_src/enacl_nif.c
+++ b/c_src/enacl_nif.c
@@ -477,6 +477,11 @@ ERL_NIF_TERM enif_crypto_sign_SECRETKEYBYTES(ErlNifEnv *env, int argc, ERL_NIF_T
 	return enif_make_int64(env, crypto_sign_SECRETKEYBYTES);
 }
 
+static
+ERL_NIF_TERM enif_crypto_sign_SEEDBYTES(ErlNifEnv *env, int argc, ERL_NIF_TERM const argv[]) {
+	return enif_make_int64(env, crypto_sign_SEEDBYTES);
+}
+
 static
 ERL_NIF_TERM enif_crypto_sign_keypair(ErlNifEnv *env, int argc, ERL_NIF_TERM const argv[]) {
 	ErlNifBinary pk, sk;
@@ -498,6 +503,29 @@ ERL_NIF_TERM enif_crypto_sign_keypair(ErlNifEnv *env, int argc, ERL_NIF_TERM con
 	return enif_make_tuple2(env, enif_make_binary(env, &pk), enif_make_binary(env, &sk));
 }
 
+static
+ERL_NIF_TERM enif_crypto_sign_seed_keypair(ErlNifEnv *env, int argc, ERL_NIF_TERM const argv[]) {
+	ErlNifBinary pk, sk, seed;
+
+	if (
+		(argc != 1) ||
+		(!enif_inspect_binary(env, argv[0], &seed))) {
+		return enif_make_badarg(env);
+	}
+
+	if (!enif_alloc_binary(crypto_sign_PUBLICKEYBYTES, &pk)) {
+	  return nacl_error_tuple(env, "alloc_failed");
+	}
+
+	if (!enif_alloc_binary(crypto_sign_SECRETKEYBYTES, &sk)) {
+	  return nacl_error_tuple(env, "alloc_failed");
+	}
+
+	crypto_sign_seed_keypair(pk.data, sk.data, seed.data);
+
+	return enif_make_tuple2(env, enif_make_binary(env, &pk), enif_make_binary(env, &sk));
+}
+
 /*
 int crypto_sign(unsigned char *sm, unsigned long long *smlen,
                 const unsigned char *m, unsigned long long mlen,
@@ -1667,7 +1695,9 @@ static ErlNifFunc nif_funcs[] = {
 
 	{"crypto_sign_PUBLICKEYBYTES", 0, enif_crypto_sign_PUBLICKEYBYTES},
 	{"crypto_sign_SECRETKEYBYTES", 0, enif_crypto_sign_SECRETKEYBYTES},
+	{"crypto_sign_SEEDBYTES", 0, enif_crypto_sign_SEEDBYTES},
 	erl_nif_dirty_job_cpu_bound_macro("crypto_sign_keypair", 0, enif_crypto_sign_keypair),
+	erl_nif_dirty_job_cpu_bound_macro("crypto_sign_seed_keypair", 1, enif_crypto_sign_seed_keypair),
 
 	erl_nif_dirty_job_cpu_bound_macro("crypto_sign", 2, enif_crypto_sign),
 	erl_nif_dirty_job_cpu_bound_macro("crypto_sign_open", 2, enif_crypto_sign_open),
diff --git a/src/enacl.erl b/src/enacl.erl
index 15ea2c2..d6e811d 100644
--- a/src/enacl.erl
+++ b/src/enacl.erl
@@ -33,7 +33,9 @@
          %% EQC
          sign_keypair_public_size/0,
          sign_keypair_secret_size/0,
+         sign_keypair_seed_size/0,
          sign_keypair/0,
+         sign_seed_keypair/1,
          sign/2,
          sign_open/2,
          sign_detached/2,
@@ -513,6 +515,10 @@ sign_keypair_public_size() ->
 sign_keypair_secret_size() ->
     enacl_nif:crypto_sign_SECRETKEYBYTES().
 
+%% @private
+sign_keypair_seed_size() ->
+    enacl_nif:crypto_sign_SEEDBYTES().
+
 %% @doc sign_keypair/0 returns a signature keypair for signing
 %%
 %% The returned value is a map in order to make it harder to misuse keys.
@@ -522,6 +528,17 @@ sign_keypair() ->
     {PK, SK} = enacl_nif:crypto_sign_keypair(),
     #{ public => PK, secret => SK}.
 
+%% @doc sign_seed_keypair/1 returns a signature keypair based on seed for signing
+%%
+%% The returned value is a map in order to make it harder to misuse keys.
+%% @end
+-spec sign_seed_keypair(S) -> #{ atom() => binary() }
+    when
+	  S :: binary().
+sign_seed_keypair(S) ->
+    {PK, SK} = enacl_nif:crypto_sign_seed_keypair(S),
+    #{ public => PK, secret => SK}.
+
 %% @doc sign/2 signs a message with a digital signature identified by a secret key.
 %%
 %% Given a message `M' and a secret key `SK' the function will sign the message and return a signed message `SM'.
diff --git a/src/enacl_nif.erl b/src/enacl_nif.erl
index 798ef53..0675615 100644
--- a/src/enacl_nif.erl
+++ b/src/enacl_nif.erl
@@ -25,8 +25,10 @@
 
          crypto_sign_PUBLICKEYBYTES/0,
          crypto_sign_SECRETKEYBYTES/0,
+         crypto_sign_SEEDBYTES/0,
 
          crypto_sign_keypair/0,
+         crypto_sign_seed_keypair/1,
 
          crypto_sign/2,
          crypto_sign_open/2,
@@ -211,8 +213,10 @@ crypto_box_open_afternm_b(_CipherText, _Nonce, _K) -> erlang:nif_error(nif_not_l
 
 crypto_sign_PUBLICKEYBYTES() -> erlang:nif_error(nif_not_loaded).
 crypto_sign_SECRETKEYBYTES() -> erlang:nif_error(nif_not_loaded).
+crypto_sign_SEEDBYTES() -> erlang:nif_error(nif_not_loaded).
 
 crypto_sign_keypair() -> erlang:nif_error(nif_not_loaded).
+crypto_sign_seed_keypair(_S) -> erlang:nif_error(nif_not_loaded).
 crypto_sign(_M, _SK) -> erlang:nif_error(nif_not_loaded).
 crypto_sign_open(_SignedMessage, _PK) -> erlang:nif_error(nif_not_loaded).