Thus said "whoami toask" on Sat, 03 Jan 2015 17:18:04 -0500:

> *- Does the  rounds affect the disk performance, ex.:  1000 vs. 10 000
> 000**? OR it just ONLY affects the time until the password unlocks the
> CRYPT device?

Yes, unless  I'm mistaken, it really  only affects how long  it takes to
generate the  key from the  passphrase. Once the  key is in  memory, the
number of rounds is no longer really relevant.

Also, one of  the primary reasons for having salts/rounds  is to protect
against  offline attacks  against  the password  database (e.g.  someone
obtains /etc/master.passwd and begins to hash passwords until a match is
found) using rainbow tables. With random  salts and large rounds it will
be extremely prohibitive to crack all the passwords in the database.

In the case  of an encrypted volume, however, we  aren't talking about a
password database  with all kinds of  usernames/passwords. We're talking
about a  single key derived  from a passphrase which  means salts/rounds
don't  have the  same  implications as  they do  for  an offline  attack
against a database. In this case, it would seem that the best protection
is a larger  number of rounds (bioctl defaults to  8192 according to the
man page).

Andy
-- 
TAI64 timestamp: 4000000054a881c2

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