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diff --git a/Lib/multiprocessing/connection.py b/Lib/multiprocessing/connection.py
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--- a/Lib/multiprocessing/connection.py
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+++ b/Lib/multiprocessing/connection.py
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@@ -41,6 +41,10 @@
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 # A very generous timeout when it comes to local connections...
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 CONNECTION_TIMEOUT = 20.
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+# The hmac module implicitly defaults to using MD5.
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+# Support using a stronger algorithm for the challenge/response code:
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+HMAC_DIGEST_NAME='sha256'
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+
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 _mmap_counter = itertools.count()
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 default_family = 'AF_INET'
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@@ -700,12 +704,16 @@
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 WELCOME = b'#WELCOME#'
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 FAILURE = b'#FAILURE#'
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+def get_digestmod_for_hmac():
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+    import hashlib
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+    return getattr(hashlib, HMAC_DIGEST_NAME)
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+
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 def deliver_challenge(connection, authkey):
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     import hmac
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     assert isinstance(authkey, bytes)
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     message = os.urandom(MESSAGE_LENGTH)
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     connection.send_bytes(CHALLENGE + message)
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-    digest = hmac.new(authkey, message).digest()
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+    digest = hmac.new(authkey, message, get_digestmod_for_hmac()).digest()
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     response = connection.recv_bytes(256)        # reject large message
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     if response == digest:
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         connection.send_bytes(WELCOME)
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@@ -719,7 +727,7 @@
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     message = connection.recv_bytes(256)         # reject large message
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     assert message[:len(CHALLENGE)] == CHALLENGE, 'message = %r' % message
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     message = message[len(CHALLENGE):]
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-    digest = hmac.new(authkey, message).digest()
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+    digest = hmac.new(authkey, message, get_digestmod_for_hmac()).digest()
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     connection.send_bytes(digest)
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     response = connection.recv_bytes(256)        # reject large message
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     if response != WELCOME: