diff --git a/crypto_kdf_derive.patch b/crypto_kdf_derive.patch
new file mode 100644
index 0000000..18596b6
--- /dev/null
+++ b/crypto_kdf_derive.patch
@@ -0,0 +1,12 @@
+diff -rub libnacl-1.7.2/libnacl/__init__.py libnacl-1.7.2-patched/libnacl/__init__.py
+--- libnacl-1.7.2/libnacl/__init__.py	2020-11-03 22:34:59.000000000 +0100
++++ libnacl-1.7.2-patched/libnacl/__init__.py	2021-06-12 00:31:42.133601308 +0200
+@@ -1180,7 +1180,7 @@
+     '''
+     size = int(subkey_size)
+     buf = ctypes.create_string_buffer(size)
+-    nacl.crypto_kdf_derive_from_key(buf, subkey_size, subkey_id, context, master_key)
++    nacl.crypto_kdf_derive_from_key(buf, subkey_size, ctypes.c_ulonglong(subkey_id), context, master_key)
+     return buf.raw
+ 
+ # Key Exchange API
diff --git a/python-libnacl.changes b/python-libnacl.changes
index 960f22d..e7cd6a1 100644
--- a/python-libnacl.changes
+++ b/python-libnacl.changes
@@ -1,3 +1,8 @@
+-------------------------------------------------------------------
+Fri Jun 11 22:36:47 UTC 2021 - Niels Abspoel <aboe76@gmail.com>
+
+- add crypto_kdf_derive.patch to fix crypto_kdf_derive_from_key() on 32-bit platforms 
+
 -------------------------------------------------------------------
 Thu Feb 18 20:17:07 UTC 2021 - Niels Abspoel <aboe76@gmail.com>
 
diff --git a/python-libnacl.spec b/python-libnacl.spec
index 728347a..04cdb74 100644
--- a/python-libnacl.spec
+++ b/python-libnacl.spec
@@ -24,6 +24,7 @@ Summary:        Python bindings for libsodium based on ctypes
 License:        Apache-2.0
 URL:            https://github.com/saltstack/libnacl
 Source0:        https://github.com/saltstack/libnacl/archive/v%{version}.tar.gz#/libnacl-%{version}.tar.gz
+Patch0:         crypto_kdf_derive.patch
 BuildRequires:  %{python_module devel}
 BuildRequires:  %{python_module setuptools}
 BuildRequires:  fdupes
@@ -42,6 +43,7 @@ in libnacl/__init__.py can be pulled out and placed directly in any project to g
 
 %prep
 %setup -q -n libnacl-%{version}
+%patch0 -p1
 
 %build
 %python_build