Re: [Operators] IM Observatory and Diffie-Hellman parameters

2013-11-16 Thread Alexander Holler
Am 13.11.2013 23:18, schrieb Dave Cridland: On Wed, Nov 13, 2013 at 9:44 PM, Fedor Brunner wrote: For detailed description of various attack scenarios with calculations please read ECRYPT II Yearly Report on Algorithms and Keysizes (2011-2012) http://www.ecrypt.eu.org/documents/D.SPA.20.pdf

Re: [Operators] IM Observatory and Diffie-Hellman parameters

2013-11-13 Thread Ladycuyik tamboh
Pada 14/11/2013 5:45 AM, "Fedor Brunner" menulis: > On 13.11.2013 19:21, Dave Cridland wrote: > > On 13 Nov 2013 17:01, "Fedor Brunner" wrote: > >> There is good comparison website for key sizes recommendations: > > http://www.keylength.com/en/compare/ > >> Enter the year until when your system

Re: [Operators] IM Observatory and Diffie-Hellman parameters

2013-11-13 Thread Dave Cridland
On Wed, Nov 13, 2013 at 10:58 PM, Thijs Alkemade wrote: > > Not the same key - just multiple keys generated using the same DH group. > That's exactly what I thought you meant and what I completely failed to type. :-/ Sorry! Dave.

Re: [Operators] IM Observatory and Diffie-Hellman parameters

2013-11-13 Thread Thijs Alkemade
On 13 nov. 2013, at 23:46, Dave Cridland wrote: > On Wed, Nov 13, 2013 at 10:41 PM, Thijs Alkemade wrote: > > On 13 nov. 2013, at 19:21, Dave Cridland wrote: > >> To decrypt all communications using 1024-bit DH over a year is likely to be >> vastly bigger than for one conversation; the same

Re: [Operators] IM Observatory and Diffie-Hellman parameters

2013-11-13 Thread Dave Cridland
On Wed, Nov 13, 2013 at 10:41 PM, Thijs Alkemade wrote: > > On 13 nov. 2013, at 19:21, Dave Cridland wrote: > > To decrypt all communications using 1024-bit DH over a year is likely to > be vastly bigger than for one conversation; the same isn't true for RSA, > for example, where you could solve

Re: [Operators] IM Observatory and Diffie-Hellman parameters

2013-11-13 Thread Thijs Alkemade
On 13 nov. 2013, at 19:21, Dave Cridland wrote: > To decrypt all communications using 1024-bit DH over a year is likely to be > vastly bigger than for one conversation; the same isn't true for RSA, for > example, where you could solve the private key once. This got me pondering, and I'm not q

Re: [Operators] IM Observatory and Diffie-Hellman parameters

2013-11-13 Thread Dave Cridland
On Wed, Nov 13, 2013 at 9:44 PM, Fedor Brunner wrote: > For detailed description of various attack scenarios with calculations > please read > > ECRYPT II Yearly Report on Algorithms and Keysizes > (2011-2012) > http://www.ecrypt.eu.org/documents/D.SPA.20.pdf > > Good link; though I suspect the mo

Re: [Operators] IM Observatory and Diffie-Hellman parameters

2013-11-13 Thread Fedor Brunner
On 13.11.2013 19:21, Dave Cridland wrote: > On 13 Nov 2013 17:01, "Fedor Brunner" wrote: >> There is good comparison website for key sizes recommendations: > http://www.keylength.com/en/compare/ >> Enter the year until when your system should be protected and see the > Discrete Logarithm Group col

Re: [Operators] IM Observatory and Diffie-Hellman parameters

2013-11-13 Thread Dave Cridland
On 13 Nov 2013 17:01, "Fedor Brunner" wrote: > There is good comparison website for key sizes recommendations: http://www.keylength.com/en/compare/ > Enter the year until when your system should be protected and see the Discrete Logarithm Group column. > Yes, that site is very nice. > The scenar

Re: [Operators] IM Observatory and Diffie-Hellman parameters

2013-11-13 Thread Fedor Brunner
On 13.11.2013 17:33, Dave Cridland wrote: > On Wed, Nov 13, 2013 at 3:31 PM, Fedor Brunner > wrote: > > For example the server jabber.ccc.de uses > 2048 bit RSA public key, but > the length of the temporary key is only 1024 bit. The

Re: [Operators] IM Observatory and Diffie-Hellman parameters

2013-11-13 Thread Dave Cridland
On Wed, Nov 13, 2013 at 3:31 PM, Fedor Brunner wrote: > For example the server jabber.ccc.de uses 2048 bit RSA public key, but > the length of the temporary key is only 1024 bit. The public key score > is 90, cipher score is 90 > http://xmpp.net/result.php?domain=jabber.ccc.de&type=server Hmmm..

Re: [Operators] IM Observatory and Diffie-Hellman parameters

2013-11-13 Thread Fedor Brunner
On 13.11.2013 16:41, Jonas Wielicki wrote: > On 13.11.2013 16:31, Fedor Brunner wrote:> This information is quite > important because during DHE key exchange a >> temporary key is generated. This temporary key is used for encryption of >> the communication and the server public RSA key is used ONLY

Re: [Operators] IM Observatory and Diffie-Hellman parameters

2013-11-13 Thread Thijs Alkemade
On 13 nov. 2013, at 16:31, Fedor Brunner wrote: > Hi all, > the IM Observatory displays use of the DHE key exchange and there is a > note "Ephemeral Diffie-Hellman is a key exchange algorithm with forward > secrecy. The security depends on the Diffie-Hellman parameters used by > the server". But

Re: [Operators] IM Observatory and Diffie-Hellman parameters

2013-11-13 Thread Jonas Wielicki
On 13.11.2013 16:31, Fedor Brunner wrote:> This information is quite important because during DHE key exchange a > temporary key is generated. This temporary key is used for encryption of > the communication and the server public RSA key is used ONLY for signing > of this temporary key and NOT for

[Operators] IM Observatory and Diffie-Hellman parameters

2013-11-13 Thread Fedor Brunner
Hi all, the IM Observatory displays use of the DHE key exchange and there is a note "Ephemeral Diffie-Hellman is a key exchange algorithm with forward secrecy. The security depends on the Diffie-Hellman parameters used by the server". But the actual strength of the DH parameters is not displayed.