Actually, the _sha module is provided by shamodule.c and _md5 is provided by md5module.c and md5.c and both will be built only when your Python is not compiled with OpenSSL by default.
You can find the details in setup.py
in your Python Source tarball.
if COMPILED_WITH_PYDEBUG or not have_usable_openssl:
# The _sha module implements the SHA1 hash algorithm.
exts.append( Extension('_sha', ['shamodule.c']) )
# The _md5 module implements the RSA Data Security, Inc. MD5
# Message-Digest Algorithm, described in RFC 1321. The
# necessary files md5.c and md5.h are included here.
exts.append( Extension('_md5',
sources = ['md5module.c', 'md5.c'],
depends = ['md5.h']) )
Most often, your Python is built with Openssl library and in that case, those functions are provided by the OpenSSL libraries itself.
Now, if you want them separately, then you can build your Python without OpenSSL or better yet, you can build with pydebug option and have them.
From your Python Source tarball:
./configure --with-pydebug
make
And there you go:
>>> import _sha
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>>> _sha.__file__
'/home/senthil/python/release27-maint/build/lib.linux-i686-2.7-pydebug/_sha.so'
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