title: Pip error installing cryptography on Big Sur
body: <p>Using pip version 20.2.4, Python 3.8.2 and Big Sur 11.0.1.</p>
  <p>When I run <code>pip install cryptography</code>, I get this error:</p>
  <pre><code>  Building wheels for collected packages: cffi
      Building wheel for cffi (setup.py): started
      Building wheel for cffi (setup.py): finished with status 'error'
      ERROR: Command errored out with exit status 1:
       command: /Users/xxx/projects/xxx/venv/bin/python -u -c 'import sys, setuptools, tokenize; sys.argv[0] = '&quot;'&quot;'/private/var/folders/g8/nj6ghjhgj11j84rsjmqqb00000gn/T/pip-install-aufpkz3c/cffi/setup.py'&quot;'&quot;'; __file__='&quot;'&quot;'/private/var/folders/g8/nj6ghjhgj11j84rsjmqqb00000gn/T/pip-install-aufpkz3c/cffi/setup.py'&quot;'&quot;';f=getattr(tokenize, '&quot;'&quot;'open'&quot;'&quot;', open)(__file__);code=f.read().replace('&quot;'&quot;'\r\n'&quot;'&quot;', '&quot;'&quot;'\n'&quot;'&quot;');f.close();exec(compile(code, __file__, '&quot;'&quot;'exec'&quot;'&quot;'))' bdist_wheel -d /private/var/folders/g8/nj6ghjhgj11j84rsjmqqb00000gn/T/pip-wheel-asotxqfl
           cwd: /private/var/folders/g8/nj6ghjhgj11j84rsjmqqb00000gn/T/pip-install-aufpkz3c/cffi/
      Complete output (42 lines):
      running bdist_wheel
      running build
      running build_py
      creating build
      creating build/lib.macosx-10.14.6-x86_64-3.8
      creating build/lib.macosx-10.14.6-x86_64-3.8/cffi
      copying cffi/backend_ctypes.py -&gt; build/lib.macosx-10.14.6-x86_64-3.8/cffi
      copying cffi/error.py -&gt; build/lib.macosx-10.14.6-x86_64-3.8/cffi
      copying cffi/setuptools_ext.py -&gt; build/lib.macosx-10.14.6-x86_64-3.8/cffi
      copying cffi/__init__.py -&gt; build/lib.macosx-10.14.6-x86_64-3.8/cffi
      copying cffi/cffi_opcode.py -&gt; build/lib.macosx-10.14.6-x86_64-3.8/cffi
      copying cffi/vengine_gen.py -&gt; build/lib.macosx-10.14.6-x86_64-3.8/cffi
      copying cffi/pkgconfig.py -&gt; build/lib.macosx-10.14.6-x86_64-3.8/cffi
      copying cffi/model.py -&gt; build/lib.macosx-10.14.6-x86_64-3.8/cffi
      copying cffi/ffiplatform.py -&gt; build/lib.macosx-10.14.6-x86_64-3.8/cffi
      copying cffi/api.py -&gt; build/lib.macosx-10.14.6-x86_64-3.8/cffi
      copying cffi/vengine_cpy.py -&gt; build/lib.macosx-10.14.6-x86_64-3.8/cffi
      copying cffi/commontypes.py -&gt; build/lib.macosx-10.14.6-x86_64-3.8/cffi
      copying cffi/lock.py -&gt; build/lib.macosx-10.14.6-x86_64-3.8/cffi
      copying cffi/recompiler.py -&gt; build/lib.macosx-10.14.6-x86_64-3.8/cffi
      copying cffi/cparser.py -&gt; build/lib.macosx-10.14.6-x86_64-3.8/cffi
      copying cffi/verifier.py -&gt; build/lib.macosx-10.14.6-x86_64-3.8/cffi
      copying cffi/_cffi_include.h -&gt; build/lib.macosx-10.14.6-x86_64-3.8/cffi
      copying cffi/parse_c_type.h -&gt; build/lib.macosx-10.14.6-x86_64-3.8/cffi
      copying cffi/_embedding.h -&gt; build/lib.macosx-10.14.6-x86_64-3.8/cffi
      copying cffi/_cffi_errors.h -&gt; build/lib.macosx-10.14.6-x86_64-3.8/cffi
      running build_ext
      building '_cffi_backend' extension
      creating build/temp.macosx-10.14.6-x86_64-3.8
      creating build/temp.macosx-10.14.6-x86_64-3.8/c
      clang -Wno-unused-result -Wsign-compare -Wunreachable-code -fno-common -dynamic -DNDEBUG -g -fwrapv -O3 -Wall -iwithsysroot/System/Library/Frameworks/System.framework/PrivateHeaders -iwithsysroot/Applications/Xcode.app/Contents/Developer/Library/Frameworks/Python3.framework/Versions/3.8/Headers -arch arm64 -arch x86_64 -DUSE__THREAD -DHAVE_SYNC_SYNCHRONIZE -I/usr/local/Cellar/libffi/3.3/include -I/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/ffi -I/Users/xxxx/projects/xxxx/venv/include -I/Applications/Xcode.app/Contents/Developer/Library/Frameworks/Python3.framework/Versions/3.8/include/python3.8 -c c/_cffi_backend.c -o build/temp.macosx-10.14.6-x86_64-3.8/c/_cffi_backend.o
      c/_cffi_backend.c:5854:2: error: Apple Arm64 ABI requires ffi_prep_cif_var
      #error Apple Arm64 ABI requires ffi_prep_cif_var
       ^
      c/_cffi_backend.c:6304:9: warning: 'ffi_prep_closure' is deprecated [-Wdeprecated-declarations]
          if (ffi_prep_closure(closure, &amp;cif_descr-&gt;cif,
              ^
      /usr/local/Cellar/libffi/3.3/include/ffi.h:341:18: note: 'ffi_prep_closure' has been explicitly marked deprecated here
        __attribute__((deprecated))
                       ^
      1 warning and 1 error generated.
      error: command 'clang' failed with exit status 1
      ----------------------------------------
      ERROR: Failed building wheel for cffi
  </code></pre>
  <p>I didn't ever encounter this before I upgraded MacOS. Any idea what I can try?</p>