diff --git a/c_src/enacl_nif.c b/c_src/enacl_nif.c
index bc31603..c52caf1 100644
--- a/c_src/enacl_nif.c
+++ b/c_src/enacl_nif.c
@@ -210,6 +210,27 @@ enif_crypto_sign_ed25519_keypair(ErlNifEnv *env, int argc,
                           enif_make_binary(env, &sk));
 }
 
+static ERL_NIF_TERM
+enif_crypto_sign_ed25519_sk_to_pk(ErlNifEnv *env, int argc,
+                                  ERL_NIF_TERM const argv[]) {
+  ErlNifBinary pk, sk;
+
+  if ((argc != 1) || (!enif_inspect_binary(env, argv[0], &sk)) ||
+      (sk.size != crypto_sign_ed25519_SECRETKEYBYTES)) {
+    return enif_make_badarg(env);
+  }
+
+  if (!enif_alloc_binary(crypto_sign_ed25519_PUBLICKEYBYTES, &pk)) {
+    return nacl_error_tuple(env, "alloc_failed");
+  }
+
+  if (crypto_sign_ed25519_sk_to_pk(pk.data, sk.data) != 0) {
+    return nacl_error_tuple(env, "crypto_sign_ed25519_sk_to_pk_failed");
+  }
+
+  return enif_make_binary(env, &pk);
+}
+
 static ERL_NIF_TERM
 enif_crypto_sign_ed25519_public_to_curve25519(ErlNifEnv *env, int argc,
                                               ERL_NIF_TERM const argv[]) {
@@ -1832,6 +1853,7 @@ static ErlNifFunc nif_funcs[] = {
                                       enif_crypto_sign_detached),
     erl_nif_dirty_job_cpu_bound_macro("crypto_sign_verify_detached", 3,
                                       enif_crypto_sign_verify_detached),
+    {"crypto_sign_ed25519_sk_to_pk", 1, enif_crypto_sign_ed25519_sk_to_pk},
 
     {"crypto_box_SEALBYTES", 0, enif_crypto_box_SEALBYTES},
 
diff --git a/src/enacl.erl b/src/enacl.erl
index 3bb51f5..3dde78d 100644
--- a/src/enacl.erl
+++ b/src/enacl.erl
@@ -151,6 +151,7 @@
 -export([
          %% No Tests!
          crypto_sign_ed25519_keypair/0,
+         crypto_sign_ed25519_sk_to_pk/1,
          crypto_sign_ed25519_public_to_curve25519/1,
          crypto_sign_ed25519_secret_to_curve25519/1,
          crypto_sign_ed25519_public_size/0,
@@ -1004,6 +1005,12 @@ crypto_sign_ed25519_keypair() ->
     {PK, SK} = enacl_nif:crypto_sign_ed25519_keypair(),
     #{ public => PK, secret => SK }.
 
+%% @doc TODO
+%% @end
+-spec crypto_sign_ed25519_sk_to_pk(Secret :: binary()) -> binary().
+crypto_sign_ed25519_sk_to_pk(Secret) ->
+    enacl_nif:crypto_sign_ed25519_sk_to_pk(Secret).
+
 %% @doc crypto_sign_ed25519_public_to_curve25519/1 converts a given Ed 25519 public
 %% key to a Curve 25519 public key.
 %% @end
diff --git a/src/enacl_nif.erl b/src/enacl_nif.erl
index a57e562..dcf76f0 100644
--- a/src/enacl_nif.erl
+++ b/src/enacl_nif.erl
@@ -112,6 +112,7 @@
 %% Ed 25519
 -export([
          crypto_sign_ed25519_keypair/0,
+         crypto_sign_ed25519_sk_to_pk/1,
          crypto_sign_ed25519_public_to_curve25519/1,
          crypto_sign_ed25519_secret_to_curve25519/1,
          crypto_sign_ed25519_PUBLICKEYBYTES/0,
@@ -293,6 +294,7 @@ crypto_curve25519_scalarmult(_Secret, _BasePoint) -> erlang:nif_error(nif_not_lo
 crypto_curve25519_scalarmult_base(_Secret) -> erlang:nif_error(nif_not_loaded).
 
 crypto_sign_ed25519_keypair() -> erlang:nif_error(nif_not_loaded).
+crypto_sign_ed25519_sk_to_pk(_SecretKey) -> erlang:nif_error(nif_not_loaded).
 crypto_sign_ed25519_public_to_curve25519(_PublicKey) -> erlang:nif_error(nif_not_loaded).
 crypto_sign_ed25519_secret_to_curve25519(_SecretKey) -> erlang:nif_error(nif_not_loaded).
 crypto_sign_ed25519_PUBLICKEYBYTES() -> erlang:nif_error(nif_not_loaded).