From: Tyler Hicks <tyhicks@canonical.com>
To: Wiebe Cazemier <wiebe@halfgaar.net>
Cc: ecryptfs@vger.kernel.org
Subject: Re: bcrypt or other key derivation algorithm
Date: Tue, 19 Jan 2016 20:48:44 -0600 [thread overview]
Message-ID: <20160120024844.GA5623@boyd> (raw)
In-Reply-To: <477778683.231885.1453114296832.JavaMail.zimbra@halfgaar.net>
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On 2016-01-18 11:51:36, Wiebe Cazemier wrote:
> Hi,
>
> What are the thoughts on implementing bcrypt as key derivation
> algorithm? I already found a TODO in the code that ecryptfs should
> support more algorithms than just SHA512 * 65536. I tried brute
> forcing this, and got no further than about 20/s, but on FPGAs/GPUs
> this would be a lot faster.
bcrypt would be a fine kdf.
> It should be easy enough to borrow code from OpenSSH, which uses
> bcrypt in their secure new private key file format (ssh-keygen -o;
> their old format is pretty weak (MD5 once, encrypt with AES 128)).
>
> Questions:
>
> 1) The v2 wrapped does not have a field to indicate which algorithm is
> used (like /etc/shadow (crypt API) has). Does this necessitate a
> v3, which does have said field?
Yes. The v2 wrapped passphrase format was intended to be the most simple
fix possible for CVE-2014-9687 in order to make backporting to stable
releases and transparent upgrades easy.
The thought was always that a v3 would be needed to support greater
algorithm agility.
> 2) Are there objections to including BSD licensed code from OpenSSH?
That bit of code looks like it is under the 4-clause BSD license. I
think that'll be a problem since the ecryptfs-utils project is GPLv2.
Can you reuse the crypt(3) interface, passing the "2a" ID for bcrypt?
Tyler
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next prev parent reply other threads:[~2016-01-20 2:48 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <148109963.231852.1453113382610.JavaMail.zimbra@halfgaar.net>
2016-01-18 10:51 ` bcrypt or other key derivation algorithm Wiebe Cazemier
2016-01-18 11:00 ` Sylvain Pelissier
2016-01-19 8:35 ` Wiebe Cazemier
2016-01-29 22:34 ` Tyler Hicks
2016-02-01 9:50 ` Wiebe Cazemier
2016-01-20 2:54 ` Tyler Hicks
2016-01-20 2:48 ` Tyler Hicks [this message]
2016-01-20 19:33 ` Wiebe Cazemier
2016-01-29 22:19 ` Tyler Hicks
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