[Sugar-devel] [PATCH 2/2 sugar] Create new owner keys as RSA keys instead of DSA

[Walter Bender]

On Tue, Nov 15, 2011 at 9:23 AM, Samuel Greenfeld <greenfeld at laptop.org> wrote:
> My last two jobs significantly involved encryption, but I am not that good
> of an amateur cryptographer.
>
> Has anyone in the security field (such as Ivan Krstić) reviewed this
> proposal?  Are there any potential performance impacts by switching key
> types for slower systems such as the XO-1?
>
> We may also want to support handling an ECDSA SSH key if we see one,
> although generating one may not always be possible (some distributions
> remove this algorithm due to patent concerns).

As I recall, Fedora pulled support for ECDSA due to patent concerns,
hence we abandoned that route relatively early-on in the Sugar
development process.

-walter
>
> ---
> SJG
>
>
> On Tue, Nov 15, 2011 at 7:35 AM, Sascha Silbe <silbe at activitycentral.com>
> wrote:
>>
>> Sugar currently uses the owner key as an opaque string, not as an actual
>> key.
>> This means the key type does not yet matter, we can just as easily use an
>> RSA
>> key. The most important reason to prefer DSA over RSA, the RSA patent, has
>> expired in 2000 [1]. While DSA is considered secure when used correctly,
>> it
>> relies on certain properties (e.g. a cryptographically secure PRNG [1])
>> that
>> have not always been met in practice [3], with secret key exposure as a
>> result [4]. RSA is less problematic in this regard.
>>
>> RSA keys are also more readily usable with other tools (e.g. monkeysphere
>> only
>> supports RSA keys [5]), enabling Sugar to use a single key to identify the
>> user for other protocols and purposes than just Collaboration. Examples
>> that
>> come to mind instantly are web browsing (think a.sl.o) and email
>> (OpenPGP).
>>
>> [1] http://en.wikipedia.org/wiki/RSA
>> [2] http://rdist.root.org/2010/11/19/dsa-requirements-for-random-k-value/
>> [3] http://www.debian.org/security/2008/dsa-1571
>> [4]
>> http://rdist.root.org/2009/05/17/the-debian-pgp-disaster-that-almost-was/
>> [5] http://web.monkeysphere.info/news/release-0.24-1/
>>
>> Signed-off-by: Sascha Silbe <silbe at activitycentral.com>
>> ---
>>  src/jarabe/intro/window.py |    2 +-
>>  1 files changed, 1 insertions(+), 1 deletions(-)
>>
>> diff --git a/src/jarabe/intro/window.py b/src/jarabe/intro/window.py
>> index f7937b1..6cf1481 100644
>> --- a/src/jarabe/intro/window.py
>> +++ b/src/jarabe/intro/window.py
>> @@ -47,7 +47,7 @@ def create_profile(name, color=None):
>>     import commands
>>     keypath = os.path.join(env.get_profile_path(), 'owner.key')
>>     if not os.path.isfile(keypath):
>> -        cmd = "ssh-keygen -q -t dsa -f %s -C '' -N ''" % keypath
>> +        cmd = "ssh-keygen -q -t rsa -f %s -C '' -N ''" % keypath
>>         (s, o) = commands.getstatusoutput(cmd)
>>         if s != 0:
>>             logging.error('Could not generate key pair: %d %s', s, o)
>> --
>> 1.7.7.1
>>
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>
>
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>



-- 
Walter Bender
Sugar Labs
http://www.sugarlabs.org