diff --git a/pkgs/epnix/support/opcua/default.nix b/pkgs/epnix/support/opcua/default.nix
index 73eaa9f3..b57fa829 100644
--- a/pkgs/epnix/support/opcua/default.nix
+++ b/pkgs/epnix/support/opcua/default.nix
@@ -1,5 +1,4 @@
 {
-  lib,
   epnixLib,
   mkEpicsPackage,
   fetchFromGitHub,
@@ -10,44 +9,45 @@
   libxml2,
   local_config_site ? {},
   local_release ? {},
-}:
-mkEpicsPackage {
-  pname = "opcua";
-  version = "0.10.0-dev";
-  varname = "OPCUA";
+}: let
+  open62541' = open62541.override {withEncryption = "openssl";};
+in
+  mkEpicsPackage {
+    pname = "opcua";
+    version = "0.10.0-dev";
+    varname = "OPCUA";
 
-  src = fetchFromGitHub {
-    owner = "epics-modules";
-    repo = "opcua";
-    rev = "3d10053";
-    hash = "sha256-EQra8PesO7Rlhj+pBlAfiqh5yjJwRkuh7gbGziY58iI=";
-  };
-
-  inherit local_release;
-  local_config_site =
-    local_config_site
-    // {
-      OPEN62541 = "${open62541}";
-      OPEN62541_DEPLOY_MODE = "PROVIDED";
-      OPEN62541_LIB_DIR = "${open62541}/lib";
-      OPEN62541_SHRLIB_DIR = "${open62541}/lib";
-      #for the moment, we're not able to use the last version of openssl to manage a safety connection with the open62541 librairy
-      OPEN62541_USE_CRYPTO = "NO";
-      OPEN62541_USE_XMLPARSER = "YES";
+    src = fetchFromGitHub {
+      owner = "epics-modules";
+      repo = "opcua";
+      rev = "3d10053";
+      hash = "sha256-EQra8PesO7Rlhj+pBlAfiqh5yjJwRkuh7gbGziY58iI=";
     };
 
-  patches = [./dir_xml2.patch];
+    inherit local_release;
+    local_config_site =
+      local_config_site
+      // {
+        OPEN62541 = "${open62541'}";
+        OPEN62541_DEPLOY_MODE = "PROVIDED";
+        OPEN62541_LIB_DIR = "${open62541'}/lib";
+        OPEN62541_SHRLIB_DIR = "${open62541'}/lib";
+        OPEN62541_USE_CRYPTO = "YES";
+        OPEN62541_USE_XMLPARSER = "YES";
+      };
+
+    patches = [./dir_xml2.patch];
 
-  depsBuildBuild = [pkg-config];
-  nativeBuildInputs = [pkg-config open62541 openssl libxml2];
-  buildInputs = [open62541 openssl libxml2];
-  propagatedNativeBuildInputs = [pkg-config];
-  propagatedBuildInputs = [libxml2] ++ (with epnix.support; [gtest]);
+    depsBuildBuild = [pkg-config];
+    nativeBuildInputs = [pkg-config open62541' openssl libxml2];
+    buildInputs = [open62541' openssl libxml2];
+    propagatedNativeBuildInputs = [pkg-config];
+    propagatedBuildInputs = [libxml2] ++ (with epnix.support; [gtest]);
 
-  meta = {
-    description = "EPICS support for communication with OPC UA protocol";
-    homepage = "https://github.com/epics-modules/opcua";
-    license = epnixLib.licenses.epics;
-    maintainers = with epnixLib.maintainers; [vivien];
-  };
-}
+    meta = {
+      description = "EPICS support for communication with OPC UA protocol";
+      homepage = "https://github.com/epics-modules/opcua";
+      license = epnixLib.licenses.epics;
+      maintainers = with epnixLib.maintainers; [vivien];
+    };
+  }