Issue #26390: Fix and test pbkdf2_hmac() parameter names

Based on patch by Daan Bakker.

Doc/library/hashlib.rst

@@ -185,22 +185,23 @@ brute-force attacks. A good password hashing function must be tunable, slow, and
 include a `salt <https://en.wikipedia.org/wiki/Salt_%28cryptography%29>`_.
 
 
-.. function:: pbkdf2_hmac(name, password, salt, rounds, dklen=None)
+.. function:: pbkdf2_hmac(hash_name, password, salt, iterations, dklen=None)
 
    The function provides PKCS#5 password-based key derivation function 2. It
    uses HMAC as pseudorandom function.
 
-   The string *name* is the desired name of the hash digest algorithm for
+   The string *hash_name* is the desired name of the hash digest algorithm for
    HMAC, e.g. 'sha1' or 'sha256'. *password* and *salt* are interpreted as
    buffers of bytes. Applications and libraries should limit *password* to
-   a sensible value (e.g. 1024). *salt* should be about 16 or more bytes from
+   a sensible length (e.g. 1024). *salt* should be about 16 or more bytes from
    a proper source, e.g. :func:`os.urandom`.
 
-   The number of *rounds* should be chosen based on the hash algorithm and
-   computing power. As of 2013, at least 100,000 rounds of SHA-256 is suggested.
+   The number of *iterations* should be chosen based on the hash algorithm and
+   computing power. As of 2013, at least 100,000 iterations of SHA-256 are
+   suggested.
 
    *dklen* is the length of the derived key. If *dklen* is ``None`` then the
-   digest size of the hash algorithm *name* is used, e.g. 64 for SHA-512.
+   digest size of the hash algorithm *hash_name* is used, e.g. 64 for SHA-512.
 
    >>> import hashlib, binascii
    >>> dk = hashlib.pbkdf2_hmac('sha256', b'password', b'salt', 100000)

Lib/test/test_hashlib.py

@@ -513,6 +513,9 @@ class KDFTests(unittest.TestCase):
         self.assertRaises(ValueError, pbkdf2, 'sha1', b'pass', b'salt', 1, -1)
         with self.assertRaisesRegex(ValueError, 'unsupported hash type'):
             pbkdf2('unknown', b'pass', b'salt', 1)
+        out = pbkdf2(hash_name='sha1', password=b'password', salt=b'salt',
+            iterations=1, dklen=None)
+        self.assertEqual(out, self.pbkdf2_results['sha1'][0][0])
 
     def test_pbkdf2_hmac_py(self):
         self._test_pbkdf2_hmac(py_hashlib.pbkdf2_hmac)