diff -r 646c2388d8f5 Doc/library/hmac.rst
--- a/Doc/library/hmac.rst	Sun Aug 18 12:43:24 2013 +0200
+++ b/Doc/library/hmac.rst	Sun Aug 18 18:28:27 2013 +0200
@@ -72,6 +72,25 @@
    compute the digests of strings that share a common initial substring.
 
 
+A hash object has the following attributes:
+
+.. attribute:: HMAC.digest_size
+
+   The size of the resulting HMAC digest in bytes.
+
+.. attribute:: HMAC.block_size
+
+   The internal block size of the hash algorithm in bytes.
+
+   .. versionadded:: 3.4
+
+.. attribute:: HMAC.name
+
+   The canonical name of this HMAC, always lowercase, e.g. ``hmac-md5``.
+
+   .. versionadded:: 3.4
+
+
 This module also provides the following helper function:
 
 .. function:: compare_digest(a, b)
diff -r 646c2388d8f5 Lib/hmac.py
--- a/Lib/hmac.py	Sun Aug 18 12:43:24 2013 +0200
+++ b/Lib/hmac.py	Sun Aug 18 18:28:27 2013 +0200
@@ -63,6 +63,10 @@
                            RuntimeWarning, 2)
             blocksize = self.blocksize
 
+        # self.blocksize is the default blocksize. self.block_size is
+        # effective block size as well as the public API attribute.
+        self.block_size = blocksize
+
         if len(key) > blocksize:
             key = self.digest_cons(key).digest()
 
@@ -72,6 +76,10 @@
         if msg is not None:
             self.update(msg)
 
+    @property
+    def name(self):
+        return "hmac-" + self.inner.name
+
     def update(self, msg):
         """Update this hashing object with the string msg.
         """
diff -r 646c2388d8f5 Lib/test/test_hmac.py
--- a/Lib/test/test_hmac.py	Sun Aug 18 12:43:24 2013 +0200
+++ b/Lib/test/test_hmac.py	Sun Aug 18 18:28:27 2013 +0200
@@ -11,6 +11,9 @@
 
         def md5test(key, data, digest):
             h = hmac.HMAC(key, data)
+            self.assertEqual(h.name, "hmac-md5")
+            self.assertEqual(h.digest_size, 16)
+            self.assertEqual(h.block_size, 64)
             self.assertEqual(h.hexdigest().upper(), digest.upper())
 
         md5test(b"\x0b" * 16,
@@ -45,6 +48,9 @@
     def test_sha_vectors(self):
         def shatest(key, data, digest):
             h = hmac.HMAC(key, data, digestmod=hashlib.sha1)
+            self.assertEqual(h.name, "hmac-sha1")
+            self.assertEqual(h.digest_size, 20)
+            self.assertEqual(h.block_size, 64)
             self.assertEqual(h.hexdigest().upper(), digest.upper())
 
         shatest(b"\x0b" * 20,
@@ -76,9 +82,12 @@
                  b"and Larger Than One Block-Size Data"),
                 "e8e99d0f45237d786d6bbaa7965c7808bbff1a91")
 
-    def _rfc4231_test_cases(self, hashfunc):
+    def _rfc4231_test_cases(self, hashfunc, hmac_name, digest_size, block_size):
         def hmactest(key, data, hexdigests):
             h = hmac.HMAC(key, data, digestmod=hashfunc)
+            self.assertEqual(h.name, hmac_name)
+            self.assertEqual(h.digest_size, digest_size)
+            self.assertEqual(h.block_size, block_size)
             self.assertEqual(h.hexdigest().lower(), hexdigests[hashfunc])
 
         # 4.2.  Test Case 1
@@ -189,16 +198,16 @@
                  })
 
     def test_sha224_rfc4231(self):
-        self._rfc4231_test_cases(hashlib.sha224)
+        self._rfc4231_test_cases(hashlib.sha224, "hmac-sha224", 28, 64)
 
     def test_sha256_rfc4231(self):
-        self._rfc4231_test_cases(hashlib.sha256)
+        self._rfc4231_test_cases(hashlib.sha256, "hmac-sha256", 32, 64)
 
     def test_sha384_rfc4231(self):
-        self._rfc4231_test_cases(hashlib.sha384)
+        self._rfc4231_test_cases(hashlib.sha384, "hmac-sha384", 48, 128)
 
     def test_sha512_rfc4231(self):
-        self._rfc4231_test_cases(hashlib.sha512)
+        self._rfc4231_test_cases(hashlib.sha512, "hmac-sha512", 64, 128)
 
     def test_legacy_block_size_warnings(self):
         class MockCrazyHash(object):