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Re: Function Points

From anton@mips.complang.tuwien.ac.at (Anton Ertl)
Newsgroups comp.lang.forth
Subject Re: Function Points
Date 2012-09-01 14:27 +0000
Organization Institut fuer Computersprachen, Technische Universitaet Wien
Message-ID <2012Sep1.162733@mips.complang.tuwien.ac.at> (permalink)
References (7 earlier) <k1phj0$lr8$1@speranza.aioe.org> <b-mdnS3hM6567d3NnZ2dnUVZ8midnZ2d@supernews.com> <k1rfal$jji$1@speranza.aioe.org> <2390503.SVvU42HMcm@sunwukong.fritz.box> <7x8vcunskj.fsf@ruckus.brouhaha.com>

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Paul Rubin <no.email@nospam.invalid> writes:
>Bernd Paysan <bernd.paysan@gmx.de> writes:
>> Nope.  The only thing you have to keep secret is the actual value you 
>> are xoring with.
>
>Xoring with some constant is not necessarily good enough (it amounts to
>initializing the hash calculation with a fixed secret value):
>
>  http://www.eng.tau.ac.il/~yash/C2_039_Wool.pdf
>
>The original Crosby and Wallach paper suggested a fancier approach using
>universal hashing (i.e. with crypto primitives).  That's slower on
>regular CPU's but with AES hardware showing up in recent x86's, maybe
>it's the best way, if you want to stay with hash tables.

Cryptographic hashes won't help at all against the attack described in
the paper above (and the paper already mentions that in the abstract),
and the reason is explained by Bernd and by footnote 2 of the paper
above: Whatever the hash function is, if you only have 2^10 or 2^13
buckets, it is easy to find values that collide in the hash table.

However, the attack works by using exhaustive search over the possible
secret values.  The authors claim it is realistic for secret values of
13-14 bits (it needs about 1000 packets per possible secret value).
I, of course would use a full word (32 or 64 bits) as a secret value,
and I don't think that an exhaustive search against that is realistic
(it would require sending about 2^42 packets, which will take a long
time).  Actually, in their conclusion the authors write "Thus, it
seems that a random value of 32 bits would render this attack
impractical with today's technology."

- anton
-- 
M. Anton Ertl  http://www.complang.tuwien.ac.at/anton/home.html
comp.lang.forth FAQs: http://www.complang.tuwien.ac.at/forth/faq/toc.html
     New standard: http://www.forth200x.org/forth200x.html
   EuroForth 2012: http://www.euroforth.org/ef12/

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Comparative Productivity of Programming Languages visualforth@rocketmail.com - 2012-08-21 21:43 -0700
  Re: Comparative Productivity of Programming Languages "A. K." <akk@nospam.org> - 2012-08-22 07:07 +0200
  Re: Comparative Productivity of Programming Languages Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-08-22 03:35 -0500
    Re: Comparative Productivity of Programming Languages John Passaniti <john.passaniti@gmail.com> - 2012-08-22 14:06 -0700
      Function Points (was: Comparative Productivity of Programming Languages) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-08-23 14:50 +0000
        Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-23 11:43 -0700
          Re: Function Points anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-08-25 14:13 +0000
            Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-25 10:12 -0700
              Re: Function Points Doug Hoffman <glidedog@gmail.com> - 2012-08-25 15:39 -0400
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-25 15:09 -0700
                Re: Function Points "Elizabeth D. Rather" <erather@forth.com> - 2012-08-25 12:34 -1000
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-25 16:43 -0700
                Re: Function Points jacko <jackokring@gmail.com> - 2012-08-25 18:05 -0700
                Re: Function Points jacko <jackokring@gmail.com> - 2012-08-25 20:34 -0700
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-08-26 03:24 +0200
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-25 22:44 -0700
                Re: Function Points "Elizabeth D. Rather" <erather@forth.com> - 2012-08-25 21:19 -1000
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-26 00:36 -0700
                Re: Function Points "Elizabeth D. Rather" <erather@forth.com> - 2012-08-25 21:50 -1000
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-26 01:08 -0700
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-08-26 23:20 +0200
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-26 19:33 -0700
                Re: Function Points Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-08-27 13:34 -0500
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-08-27 22:38 +0200
                Re: Function Points Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-08-28 02:45 -0500
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-27 18:14 -0700
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-27 18:24 -0700
                Re: Function Points anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-08-30 14:22 +0000
                Re: Function Points Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-08-28 03:07 -0500
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-28 08:18 -0700
                Re: Function Points Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-08-28 12:15 -0500
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-28 23:05 -0700
                Re: Function Points Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-08-29 03:55 -0500
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-08-27 22:28 +0200
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-27 20:26 -0700
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-08-28 23:17 +0200
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-29 01:13 -0700
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-29 02:23 -0700
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-08-30 02:59 +0200
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-29 22:18 -0700
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-08-30 20:44 +0200
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-31 01:29 -0700
                Re: Function Points anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-08-31 09:33 +0000
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-08-30 02:58 +0200
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-29 19:39 -0700
                Re: Function Points anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-08-30 14:10 +0000
                Re: Function Points gavino_himself <visploveslisp@gmail.com> - 2012-08-30 20:08 -0700
                Re: Function Points "Elizabeth D. Rather" <erather@forth.com> - 2012-08-30 17:47 -1000
                Re: Function Points "Elizabeth D. Rather" <erather@forth.com> - 2012-08-27 13:43 -1000
                Re: Function Points "Paul E. Bennett" <Paul_E.Bennett@topmail.co.uk> - 2012-08-27 12:14 +0100
                Re: Function Points Mark Wills <markrobertwills@yahoo.co.uk> - 2012-08-27 05:12 -0700
                Re: Function Points "Paul E. Bennett" <Paul_E.Bennett@topmail.co.uk> - 2012-08-27 15:52 +0100
                Re: Function Points anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-08-26 13:09 +0000
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-27 20:52 -0700
                Re: Function Points anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-08-30 14:08 +0000
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-30 10:43 -0700
                Re: Function Points "Elizabeth D. Rather" <erather@forth.com> - 2012-08-30 08:25 -1000
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-08-30 22:42 +0200
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-08-31 01:23 -0400
                Re: Function Points Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-08-31 03:08 -0500
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-08-31 18:56 -0400
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-01 02:35 +0200
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-31 23:52 -0700
                Re: Function Points anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-09-01 14:27 +0000
                Re: Function Points anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-09-01 14:18 +0000
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-01 17:45 +0200
                Re: Function Points anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-09-01 16:14 +0000
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-01 19:13 +0200
                Re: Function Points Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-09-02 03:19 -0500
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-01 16:18 -0400
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-02 03:04 +0200
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-02 04:02 -0400
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-02 17:40 +0200
                Re: Function Points jim@rainbarrel.com - 2012-09-02 10:32 -0700
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-02 20:49 +0200
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-02 16:33 -0400
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-02 17:03 -0400
                Re: Function Points "Elizabeth D. Rather" <erather@forth.com> - 2012-09-02 09:02 -1000
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-02 16:35 -0400
                Re: Function Points "Elizabeth D. Rather" <erather@forth.com> - 2012-09-02 13:42 -1000
                Re: Function Points jim@rainbarrel.com - 2012-09-02 16:54 -0700
                Re: Function Points Mark Wills <markrobertwills@yahoo.co.uk> - 2012-09-03 00:29 -0700
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-03 01:30 -0400
                Re: Function Points "Elizabeth D. Rather" <erather@forth.com> - 2012-09-02 21:21 -1000
                Re: Function Points jim@rainbarrel.com - 2012-09-03 10:37 -0700
                Re: Function Points anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-09-04 07:14 +0000
                Re: Function Points Coos Haak <chforth@hccnet.nl> - 2012-09-03 21:12 +0200
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-03 17:32 -0400
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-03 17:51 -0400
                Re: Function Points John Passaniti <john.passaniti@gmail.com> - 2012-09-03 22:37 -0700
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-04 04:25 -0400
                Re: Function Points John Passaniti <john.passaniti@gmail.com> - 2012-09-04 07:35 -0700
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-05 02:13 -0400
                Re: Function Points "Elizabeth D. Rather" <erather@forth.com> - 2012-09-04 20:18 -1000
                Re: Function Points John Passaniti <john.passaniti@gmail.com> - 2012-09-05 10:56 -0700
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-05 16:11 -0400
                Re: Function Points John Passaniti <john.passaniti@gmail.com> - 2012-09-05 14:07 -0700
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-02 16:27 -0400
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-03 00:52 +0200
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-09-02 16:28 -0700
                Re: Function Points jim@rainbarrel.com - 2012-09-02 16:48 -0700
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-02 20:21 -0400
                Re: Function Points "Elizabeth D. Rather" <erather@forth.com> - 2012-09-02 14:45 -1000
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-03 01:12 -0400
                Re: Function Points "Elizabeth D. Rather" <erather@forth.com> - 2012-09-02 21:26 -1000
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-03 01:06 -0400
                Re: Function Points Mark Wills <markrobertwills@yahoo.co.uk> - 2012-08-31 03:29 -0700
                Re: Function Points anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-08-31 10:35 +0000
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-08-31 18:49 -0400
                Re: Function Points anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-09-01 14:49 +0000
                Re: Function Points "Elizabeth D. Rather" <erather@forth.com> - 2012-09-01 08:36 -1000
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-01 16:11 -0400
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-03 01:58 +0200
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-01 17:54 +0200
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-01 16:19 -0400
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-02 03:05 +0200
                Re: Function Points Coos Haak <chforth@hccnet.nl> - 2012-08-31 23:10 +0200
                Re: Function Points "Elizabeth D. Rather" <erather@forth.com> - 2012-08-31 15:50 -1000
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-09-01 10:31 -0700
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-01 21:52 +0200
                Re: Function Points "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-09-01 16:36 -0400
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-09-01 14:36 -0700
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-02 03:30 +0200
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-02 23:15 +0200
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-09-02 15:02 -0700
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-03 01:50 +0200
                Re: Function Points jim@rainbarrel.com - 2012-09-02 16:57 -0700
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-09-03 23:11 -0700
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-04 14:30 +0200
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-09-04 10:14 -0700
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-04 22:10 +0200
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-09-06 00:19 -0700
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-06 17:48 +0200
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-09-06 12:01 -0700
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-06 22:02 +0200
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-09-06 14:19 -0700
                Heap (was: Function Points) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-09-07 11:30 +0000
                Re: Heap (was: Function Points) Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-07 18:12 +0200
                Re: Heap (was: Function Points) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-09-07 16:48 +0000
                Re: Heap (was: Function Points) Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-07 21:34 +0200
                Re: Heap Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2012-09-07 22:04 +0100
                Re: Heap anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-09-08 11:52 +0000
                Re: Heap Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-08 22:48 +0200
                Re: Heap (was: Function Points) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-09-08 12:11 +0000
                priority queue (was: Function Points) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-09-03 11:46 +0000
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-03 15:03 +0200
                Re: Function Points mhx@iae.nl (Marcel Hendrix) - 2012-09-03 22:36 +0200
                Re: Function Points mhx@iae.nl (Marcel Hendrix) - 2012-09-06 20:27 +0200
                Re: Function Points Andrew Haley <andrew29@littlepinkcloud.invalid> - 2012-09-02 04:00 -0500
                Re: Function Points visualforth@rocketmail.com - 2012-09-03 10:40 -0700
                Re: Function Points Bernd Paysan <bernd.paysan@gmx.de> - 2012-09-03 20:26 +0200
                Re: Function Points Doug Hoffman <glidedog@gmail.com> - 2012-08-27 11:49 -0400
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-27 09:16 -0700
                Re: Function Points Josh Grams <josh@qualdan.com> - 2012-08-28 22:46 +0000
                Re: Function Points jacko <jackokring@gmail.com> - 2012-08-28 16:06 -0700
                Re: Function Points Doug Hoffman <glidedog@gmail.com> - 2012-08-28 20:50 -0400
              Re: Function Points anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-08-26 12:59 +0000
                Re: Function Points Paul Rubin <no.email@nospam.invalid> - 2012-08-26 22:24 -0700
        Re: Function Points (was: Comparative Productivity of Programming Languages) John Passaniti <john.passaniti@gmail.com> - 2012-08-23 15:02 -0700
          Re: Function Points (was: Comparative Productivity of Programming Languages) anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2012-08-25 14:57 +0000
  Re: Comparative Productivity of Programming Languages "Rod Pemberton" <do_not_have@notemailnot.cmm> - 2012-08-22 08:07 -0400
    Re: Comparative Productivity of Programming Languages visualforth@rocketmail.com - 2012-08-22 08:12 -0700
  Re: Comparative Productivity of Programming Languages visualforth@rocketmail.com - 2012-08-22 07:37 -0700

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