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Message-ID: <008d01cf0b33$cbf03b30$63d0b190$@cfl.rr.com>
Date: Mon, 6 Jan 2014 18:05:30 -0500
From: "Gary W. Hvizdak" <gary.hvizdak@....rr.com>
To: <discussions@...sword-hashing.net>
Subject: RE: [PHC] Submission deadline extension (March 31)
Hi JP,
Thank you, thank you, thank you! This is the wonderful news.
And while I'm writing . currently I am debating the addition of yet
another formal parameter, but for the moment here's my public function's
prototype .
int PHC (
void * out,
size_t outlen,
const void * in,
size_t inlen,
const void * salt,
size_t saltlen,
unsigned int t_cost,
unsigned int m_cost,
unsigned int * cost_t, // "effective" time-cost (optional)
unsigned int * cost_m, // "effective" memory-cost (optional)
unsigned int lo_seed, // 32-bit seed used to minimize
memory-cost's "time impact"
unsigned int hi_seed, // top half of 64-bit seed (as described
above)
unsigned int flags) // currently four flags are supported
(described below <> )
The parameter I'm currently debating adding is "max_inlen". Its purpose
would be to minimize time wasted in environments where the maximum password
length "ever expected" is considerably .LT. 128. Thus allowing a
substantially higher time-cost parameter value - i.e. doing additional
calculating as opposed to just spinning our wheels - and thereby stronger
hashing.
Thanks,
Gary
P.S. My "baby" is maturing nicely; below is a brief update feature list of
the current product ...
_____
* Cost parameters are fairly independent, although memory costs above
1 MB have a rapidly increasing time-cost side effect, no doubt due to cache
misses.
o Memory costs have been demonstrated up to 256 MB, at which point I get a
malloc() error.
* Digest length can be any positive number. (I have tested with all
lengths in the range 1 to 8192 bytes, i.e. from 8 to 65536 bits in 8-bit
increments!)
* Favorable "avalanche effect" behavior.
* Easy to comprehend algorithm based on just two primitives . . .
o Arithmetic modulo.
o Fisher-Yates shuffle.
* A single (.c) source file supports 32- and 64-bit builds (via
conditionally included header files).
* Build-time "force" and "prohibit" flag-overrides. (Not yet
implemented!)
* Flags . . .
o RUN IN NEAR CONSTANT TIME
* Thwarts timing side-channel attacks. (See the preliminary plot below <>
.)
o OBLITERATE WORKING MEMORY
* Thwarts memory sniffer attacks.
o INJECT REMAINDER FEEDBACK
* Thwarts calculating all of the "password+salt" modulos in parallel via
GPUs, or custom hardware, i.e. ASIC, FPGA, etc.
* Causes the calculation to run slightly slower.
* May leak slightly more info to timing side-channel attackers.
* Alters the digest.
o RUN IN DEVELOPMENT MODE
* Enables input validation and detailed "error" return codes.
:
:
(Note that the flag "designations" in the plot legend below, do not match
the flag names in the description above.)
X-axis is password + salt = total data length, Y-axis is time in mS
Test Case Parameters : 1X memory-cost; 5X time-cost; 32-byte digest
Title: Execution Time in mS vs. Password + Salt Length
_____
-----Original Message-----
From: Jean-Philippe Aumasson [mailto:jeanphilippe.aumasson@...il.com]
Sent: Monday 06 Jan 2014 1124
To: discussions@...sword-hashing.net
Subject: [PHC] Submission deadline extension (March 31)
The submission deadline extension of PHC is extended to March 31.
This has been announced
* on the website <https://password-hashing.net/call.html>
https://password-hashing.net/call.html
<https://password-hashing.net/timeline.html>
https://password-hashing.net/timeline.html
* on Twitter <https://twitter.com/veorq/status/420225439710212097>
https://twitter.com/veorq/status/420225439710212097
* in my Dagstuhl talk of today
<https://131002.net/data/talks/norxphc_dagstuhl14.pdf>
https://131002.net/data/talks/norxphc_dagstuhl14.pdf
We hope this will increase the quality and quantity of submissions to
PHC, and that it will eventually benefit the project.
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