diff --git a/MANIFEST.in b/MANIFEST.in
--- a/MANIFEST.in
+++ b/MANIFEST.in
@@ -2,3 +2,6 @@
 include requirements*.txt
 include version.txt
 recursive-include swh py.typed
+include swh/perfecthash.c
+include swh/perfecthash.h
+include perfecthash_build.py
diff --git a/mypy.ini b/mypy.ini
--- a/mypy.ini
+++ b/mypy.ini
@@ -19,3 +19,6 @@
 
 [mypy-rados.*]
 ignore_missing_imports = True
+
+[mypy-_perfecthash_cffi.*]
+ignore_missing_imports = True
diff --git a/perfecthash_build.py b/perfecthash_build.py
new file mode 100644
--- /dev/null
+++ b/perfecthash_build.py
@@ -0,0 +1,24 @@
+from cffi import FFI
+
+ffibuilder = FFI()
+
+# cdef() expects a single string declaring the C types, functions and
+# globals needed to use the shared object. It must be in valid C syntax.
+ffibuilder.cdef(
+    """
+int build(char* path);
+"""
+)
+
+ffibuilder.set_source(
+    "_perfecthash_cffi",
+    """
+                      #include "swh/perfecthash.h"
+                      """,
+    sources=["swh/perfecthash.c"],
+    include_dirs=["."],
+    libraries=["cmph"],
+)  # library name, for the linker
+
+if __name__ == "__main__":
+    ffibuilder.compile(verbose=True)
diff --git a/requirements.txt b/requirements.txt
--- a/requirements.txt
+++ b/requirements.txt
@@ -2,6 +2,8 @@
 # should match https://pypi.python.org/pypi names. For the full spec or
 # dependency lines, see https://pip.readthedocs.org/en/1.1/requirements.html
 
+cffi
+
 # remote storage API server
 aiohttp >= 3
 click
diff --git a/setup.py b/setup.py
--- a/setup.py
+++ b/setup.py
@@ -46,10 +46,11 @@
     url="https://forge.softwareheritage.org/diffusion/DOBJS",
     packages=find_packages(),
     install_requires=parse_requirements() + parse_requirements("swh"),
-    setup_requires=["setuptools-scm"],
+    setup_requires=["setuptools-scm", "cffi"],
     use_scm_version=True,
     extras_require={"testing": parse_requirements("test")},
     include_package_data=True,
+    cffi_modules=["perfecthash_build.py:ffibuilder"],
     entry_points="""
         [swh.cli.subcommands]
         objstorage=swh.objstorage.cli
diff --git a/swh/objstorage/tests/test_perfecthash.py b/swh/objstorage/tests/test_perfecthash.py
new file mode 100644
--- /dev/null
+++ b/swh/objstorage/tests/test_perfecthash.py
@@ -0,0 +1,5 @@
+from _perfecthash_cffi import lib
+
+
+def test_build():
+    assert lib.build("path") == 0
diff --git a/swh/perfecthash.h b/swh/perfecthash.h
new file mode 100644
--- /dev/null
+++ b/swh/perfecthash.h
@@ -0,0 +1 @@
+#include <cmph.h>
diff --git a/swh/perfecthash.c b/swh/perfecthash.c
new file mode 100644
--- /dev/null
+++ b/swh/perfecthash.c
@@ -0,0 +1,5 @@
+#include "swh/perfecthash.h"
+
+int build(char *path) {
+    return 0;
+}