Issue #18011: base64.b32decode() now raises a binascii.Error if there are

non-alphabet characters present in the input string to conform a docstring.
Updated the module documentation.

diff --cc Lib/base64.py
index 0f731fa043c49bdb0a25e89b795d629432519104,b6e82b69bdd49e8f2739f06338f042264efe4880..f923244104e3bea996e3c6e5ef973a53ebaa173e
--- 1/Lib/base64.py
--- 2/Lib/base64.py
+++ b/Lib/base64.py
@@@ -209,36 -232,42 +209,36 @@@ def b32decode(s, casefold=False, map01=
      # Strip off pad characters from the right.  We need to count the pad
      # characters because this will tell us how many null bytes to remove from
      # the end of the decoded string.
 -    padchars = 0
 -    mo = re.search(b'(?P<pad>[=]*)$', s)
 -    if mo:
 -        padchars = len(mo.group('pad'))
 -        if padchars > 0:
 -            s = s[:-padchars]
 +    l = len(s)
 +    s = s.rstrip(b'=')
 +    padchars = l - len(s)
      # Now decode the full quanta
 -    parts = []
 -    acc = 0
 -    shift = 35
 -    for c in s:
 -        val = _b32rev.get(c)
 -        if val is None:
 +    decoded = bytearray()
 +    b32rev = _b32rev
 +    for i in range(0, len(s), 8):
 +        quanta = s[i: i + 8]
 +        acc = 0
 +        try:
 +            for c in quanta:
 +                acc = (acc << 5) + b32rev[c]
 +        except KeyError:
-             raise TypeError('Non-base32 digit found')
+             raise binascii.Error('Non-base32 digit found')
 -        acc += _b32rev[c] << shift
 -        shift -= 5
 -        if shift < 0:
 -            parts.append(binascii.unhexlify(bytes('%010x' % acc, "ascii")))
 -            acc = 0
 -            shift = 35
 +        decoded += acc.to_bytes(5, 'big')
      # Process the last, partial quanta
 -    last = binascii.unhexlify(bytes('%010x' % acc, "ascii"))
 -    if padchars == 0:
 -        last = b''                      # No characters
 -    elif padchars == 1:
 -        last = last[:-1]
 -    elif padchars == 3:
 -        last = last[:-2]
 -    elif padchars == 4:
 -        last = last[:-3]
 -    elif padchars == 6:
 -        last = last[:-4]
 -    else:
 -        raise binascii.Error('Incorrect padding')
 -    parts.append(last)
 -    return b''.join(parts)
 +    if padchars:
 +        acc <<= 5 * padchars
 +        last = acc.to_bytes(5, 'big')
 +        if padchars == 1:
 +            decoded[-5:] = last[:-1]
 +        elif padchars == 3:
 +            decoded[-5:] = last[:-2]
 +        elif padchars == 4:
 +            decoded[-5:] = last[:-3]
 +        elif padchars == 6:
 +            decoded[-5:] = last[:-4]
 +        else:
 +            raise binascii.Error('Incorrect padding')
 +    return bytes(decoded)
  
  
  

diff --cc Misc/NEWS
index fd2978f3600e92cdf418ed663ff7695ff4e2e3c8,41bc85645a5ba0627543f5e7a7c55c1b7f876622..04e9d15470d971274c007dccd07deac963c768fd
--- 1/Misc/NEWS
--- 2/Misc/NEWS
+++ b/Misc/NEWS
@@@ -103,47 -127,6 +103,51 @@@ Core and Builtin
  Library
  -------
  
++- Issue #18011: base64.b32decode() now raises a binascii.Error if there are
++  non-alphabet characters present in the input string to conform a docstring.
++  Updated the module documentation.
++
 +- Issue #18072: Implement importlib.abc.InspectLoader.get_code() and
 +  importlib.abc.ExecutionLoader.get_code().
 +
 +- Issue #8240: Set the SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER flag on SSL
 +  sockets.
 +
 +- Issue #17269: Workaround for socket.getaddrinfo crash on MacOS X
 +  with port None or "0" and flags AI_NUMERICSERV.
 +
 +- Issue #16986: ElementTree now correctly parses a string input not only when
 +  an internal XML encoding is UTF-8 or US-ASCII.
 +
 +- Issue #17996: socket module now exposes AF_LINK constant on BSD and OSX.
 +
 +- Issue #17900: Allowed pickling of recursive OrderedDicts.  Decreased pickled
 +  size and pickling time.
 +
 +- Issue #17914: Add os.cpu_count(). Patch by Yogesh Chaudhari, based on an
 +  initial patch by Trent Nelson.
 +
 +- Issue #17812: Fixed quadratic complexity of base64.b32encode().
 +  Optimize base64.b32encode() and base64.b32decode() (speed up to 3x).
 +
 +- Issue #17980: Fix possible abuse of ssl.match_hostname() for denial of
 +  service using certificates with many wildcards (CVE-2013-2099).
 +
 +- Issue #15758: Fix FileIO.readall() so it no longer has O(n**2) complexity.
 +
 +- Issue #14596: The struct.Struct() objects now use more compact implementation.
 +
 +- Issue #17981: Closed socket on error in SysLogHandler.
 +
 +- Issue #17964: Fix os.sysconf(): the return type of the C sysconf() function
 +  is long, not int.
 +
 +- Fix typos in the multiprocessing module.
 +
 +- Issue #17754: Make ctypes.util.find_library() independent of the locale.
 +
 +- Issue #17968: Fix memory leak in os.listxattr().
 +
  - Issue #17606: Fixed support of encoded byte strings in the XMLGenerator
    characters() and ignorableWhitespace() methods.  Original patch by Sebastian
    Ortiz Vasquez.