diff --git a/Lib/multiprocessing/connection.py b/Lib/multiprocessing/connection.py

--- a/Lib/multiprocessing/connection.py

+++ b/Lib/multiprocessing/connection.py

@@ -41,6 +41,10 @@

 # A very generous timeout when it comes to local connections...

 CONNECTION_TIMEOUT = 20.

+# The hmac module implicitly defaults to using MD5.

+# Support using a stronger algorithm for the challenge/response code:

+HMAC_DIGEST_NAME='sha256'

+

 _mmap_counter = itertools.count()

 default_family = 'AF_INET'

@@ -700,12 +704,16 @@

 WELCOME = b'#WELCOME#'

 FAILURE = b'#FAILURE#'

+def get_digestmod_for_hmac():

+    import hashlib

+    return getattr(hashlib, HMAC_DIGEST_NAME)

+

 def deliver_challenge(connection, authkey):

     import hmac

     assert isinstance(authkey, bytes)

     message = os.urandom(MESSAGE_LENGTH)

     connection.send_bytes(CHALLENGE + message)

-    digest = hmac.new(authkey, message).digest()

+    digest = hmac.new(authkey, message, get_digestmod_for_hmac()).digest()

     response = connection.recv_bytes(256)        # reject large message

     if response == digest:

         connection.send_bytes(WELCOME)

@@ -719,7 +727,7 @@

     message = connection.recv_bytes(256)         # reject large message

     assert message[:len(CHALLENGE)] == CHALLENGE, 'message = %r' % message

     message = message[len(CHALLENGE):]

-    digest = hmac.new(authkey, message).digest()

+    digest = hmac.new(authkey, message, get_digestmod_for_hmac()).digest()

     connection.send_bytes(digest)

     response = connection.recv_bytes(256)        # reject large message

     if response != WELCOME: