diff --git a/pkgs/development/ocaml-modules/cstruct/default.nix b/pkgs/development/ocaml-modules/cstruct/default.nix
index dd6cffb979c5..8c1aac4d83b2 100644
--- a/pkgs/development/ocaml-modules/cstruct/default.nix
+++ b/pkgs/development/ocaml-modules/cstruct/default.nix
@@ -1,5 +1,5 @@
-{ stdenv, writeText, fetchFromGitHub, ocaml, ocplib-endian, sexplib_p4, findlib, ppx_tools
-, async_p4 ? null, lwt ? null, camlp4
+{ stdenv, writeText, fetchFromGitHub, ocaml, ocplib-endian, sexplib, findlib, ppx_tools
+, async ? null, lwt ? null
 }:
 
 assert stdenv.lib.versionAtLeast ocaml.version "4.01";
@@ -22,10 +22,10 @@ stdenv.mkDerivation {
     inherit (param) sha256;
   };
 
-  configureFlags = [ "${opt lwt}-lwt" "${opt async_p4}-async" "${opt ppx_tools}-ppx" ];
+  configureFlags = [ "${opt lwt}-lwt" "${opt async}-async" "${opt ppx_tools}-ppx" ];
 
-  buildInputs = [ ocaml findlib ppx_tools camlp4 lwt async_p4 ];
-  propagatedBuildInputs = [ ocplib-endian sexplib_p4 ];
+  buildInputs = [ ocaml findlib ppx_tools lwt async ];
+  propagatedBuildInputs = [ ocplib-endian sexplib ];
 
   createFindlibDestdir = true;
   dontStrip = true;
diff --git a/pkgs/development/ocaml-modules/nocrypto/default.nix b/pkgs/development/ocaml-modules/nocrypto/default.nix
index fab048a9a9f8..d7f7ae0e3655 100644
--- a/pkgs/development/ocaml-modules/nocrypto/default.nix
+++ b/pkgs/development/ocaml-modules/nocrypto/default.nix
@@ -1,20 +1,30 @@
-{ stdenv, fetchzip, ocaml, findlib, cstruct, type_conv, zarith, ocaml_lwt, ounit }:
+{ stdenv, buildOcaml, fetchFromGitHub, ocaml, findlib
+, cstruct, zarith, ounit, ocaml_oasis, ppx_sexp_conv, sexplib
+, lwt ? null}:
 
-assert stdenv.lib.versionAtLeast ocaml.version "4.01";
+with stdenv.lib;
+let withLwt = lwt != null; in
 
-stdenv.mkDerivation rec {
-  name = "ocaml-nocrypto-${version}";
-  version = "0.5.1";
+buildOcaml rec {
+  name = "nocrypto";
+  version = "0.5.3";
 
-  src = fetchzip {
-    url = "https://github.com/mirleft/ocaml-nocrypto/archive/${version}.tar.gz";
-    sha256 = "15gffvixk12ghsfra9amfszd473c8h188zfj03ngvblbdm0d80m0";
+  minimumSupportedOcamlVersion = "4.02";
+
+  src = fetchFromGitHub {
+    owner  = "mirleft";
+    repo   = "ocaml-nocrypto";
+    rev    = "v${version}";
+    sha256 = "0m3yvqpgfffqp15mcl08b78cv8zw25rnp6z1pkj5aimz6xg3gqbl";
   };
 
-  buildInputs = [ ocaml findlib type_conv ocaml_lwt ounit ];
-  propagatedBuildInputs = [ cstruct zarith ];
+  buildInputs = [ ocaml ocaml_oasis findlib ounit ppx_sexp_conv ];
+  propagatedBuildInputs = [ cstruct zarith sexplib ] ++ optional withLwt lwt;
+
+  configureFlags = [ "--enable-tests" ] ++ optional withLwt ["--enable-lwt"];
+
+  configurePhase = "./configure --prefix $out $configureFlags";
 
-  configureFlags = "--enable-tests";
   doCheck = true;
   checkTarget = "test";
   createFindlibDestdir = true;
@@ -22,7 +32,6 @@ stdenv.mkDerivation rec {
   meta = {
     homepage = https://github.com/mirleft/ocaml-nocrypto;
     description = "Simplest possible crypto to support TLS";
-    platforms = ocaml.meta.platforms or [];
     license = stdenv.lib.licenses.bsd2;
     maintainers = with stdenv.lib.maintainers; [ vbgl ];
   };
diff --git a/pkgs/top-level/ocaml-packages.nix b/pkgs/top-level/ocaml-packages.nix
index 5e694f188e9c..c7422bdaba4a 100644
--- a/pkgs/top-level/ocaml-packages.nix
+++ b/pkgs/top-level/ocaml-packages.nix
@@ -259,7 +259,9 @@ let
 
     mlgmp =  callPackage ../development/ocaml-modules/mlgmp { };
 
-    nocrypto =  callPackage ../development/ocaml-modules/nocrypto { };
+    nocrypto =  callPackage ../development/ocaml-modules/nocrypto {
+      lwt = ocaml_lwt;
+    };
 
     ocaml_batteries = callPackage ../development/ocaml-modules/batteries { };