Loading...

Browsing monthly archives: February 2005

Asterisk Setup

SIPping away

At the recent Apricot the folk from APEET were selling wireless IP phones for a givaway price. It reminds me of the early times of 802.11 when these devices were made available for about 50-100 bucks.

So having this device inspired me to try and configure an asterisk server on my multipurpose home router/gateway. The machine I run this on is a Dell Power edge, one of these somewhat older machines with only the powersupply van as a moving components. The 300Mhz CPU (if I’m not mistaking), 96M memory. Machine runs Debian Linux and has an EICON DIVA 2.01 S/T ISA ISDN card.

I’ve installed asterisk and mucked about for a day or two, first to get incomming ISDN calls working. Once you understand the ‘channel’ and ‘context’ concepts its pretty easy to setup.

I’ve set it up so that:

  • a call to one of my MSN numbers gets rerouted to the sip phone.
  • a call from the SIP phone to “100” calls the other MSN (so I can call my wife.
  • any call starting with “0” is routed to the plain old PSTN network

So to be able to do this one needs to setup two channels, the SIP and MODEM channel and create a couple of extentions.

In sip.conf i defined the following

[olaf]
type=friend
host=dynamic
username=olaf
context=olaf_from_sip
secret= ****
dtmfmode=inband ; Choices are inband, rfc2833, or info

In modem.conf I added the following:

[interfaces]
context=isdn

group=1 ; group=1
msn=201234567 ; the incomming MSN
incomingmsn=*
device => /dev/ttyI0
device => /dev/ttyI1

In extensions.conf I have the following relevant entries:

[default]
; This is for the incomming sip calls that are addressed to sip@
; off course you need a SRV entry for
exten => olaf,1,Dial(SIP/olaf,100,r)

[olaf_from_sip]
ignorepat => 0
exten => 100,1,Dial(Modem/g1:0209876543,100,r) ; when 100 is dialed the ‘hotline’ number is called
exten => _0.,1,Dial(Modem/g1/201234567:${EXTEN}) ; any extention starting with 0 is routed to the PSTN with Caller ID 2012345657
exten => _0.,2,Congestion

[isdn] ; see modem.conf
exten => 201234567,1,Dial(SIP/olaf,100,r) ; a call on the isdn line, to 201234567 is rerouted to the SIP/olaf extention.

Setting this up is not hard indeed and it is truly remarkable that his technology is available to home users.

Corporate Crime

From the script for “Corporate Crime” starring Robbie Williams as James Bond.

Scene 34 The Drousley assassination


Drousley wakes up looks at the window, its open, he walks over and closes it. Looking surprised, that window wasn’t open. He scans the room, nothing unfamiliar. Walks back to the bed and picks up his robe from the bed. Takes some effort to stylishly and correctly knots the belt.

From the bed, walks to the hallway, bends over, picks up the paper. While scanning the headlines, walks to the toilet. Camera zooms to feet, robe falls to the floor, shorts fall on the ankles and Drousley sits down.

Split screen:
right:

After one hears a few pages flip, some ‘things’ falling into the water, hear the sound of the bottom flusher you can tell from Drousleys feet that he tries to stand up.

left:

A gloved hand opens a bottle of super glue and prepares the seat. Then the same gloved hand turns operates a dial that is slowly turned up.

right:

The feet panic, you see them kick while you hear the noise of burning flesh and screaming.

Full screen:

The kicking of the legs becomes more violent, while smoke fills the screen, from above. Suddenly the kicking stops. The paper falls on the floor. Headline shown “Drousley new CEO for Gong Inc”.

Silence.

Kyoto

Hmmm… tasty

I am in Japan, in a conference hall, and when I look around I see… chairs, walls, blinded windows. If there would have been people the differences would have been more distinct.
But now I could have been anywhere. Fortunatelly I did have a change to leave the conference center and I am getting introduced to the Japanes Kitchen.

I consider myself a foody, but not a ‘natural one’. I have not been educated as such and a lot of things that I appreciate nowadays I have tought myself to eat when I was in my late 20s.
I have been concentrating on the European kitchen mostly. I am familiar with the French and Italian kitchen. I even pretend to be able to cook. But all this pompus pretention asside I have never been properly introduced to the Japanese kitchen. Mainly because I am not so much of a fish eater. But here I am getting over it. The food is so amazingly well prepared that one just has to taste.


We went to a restaurant two days ago where we had a “surprise” dinner (only 2500 Yen), a wide variety of fish, poultry, veggies and… beef. The best beef I had in years… maybe even the best beef in my life. It came with sesame seeds and a red sauce that might have had some tomato in it but also could have been soy based. Let me not forget to mention the Duck, which appearantly is judged at proper value here too.

I hope I’m abble to find more places with surprises like this…. jummy.

I’ve seen the light…

Subversion

Recently I became responsible for the maintenance of the perl Net::DNS module. Since the previous maintainer had moved Net::DNS to a subversion directory I decided to give subversion a try. The result…

I am converted. Haleluja.

What got me going for it is that the on-line documentation describes in a very clear way how Branching and Merging works. After toying around for a bit I learned two things:

  • Use the FSFS database
  • Have a test repository available to get the hang of it before you start messing with the original repository.

The most powerfull features, and that has everything to do with branching are the "move", "copy" and "delete" features. The only thing you have to get used to are the order(6) sized version numbers you can end up with.

This is Revision 5923235 of this posting

We should have seen this comming.

SHA1, SHA2, SHA3, what’s the next hash I’m going to see.

The Feb 7 FWC.com article "Hashing out encription" first paragraph reads:

Federal agencies have been put on notice that National Institute ofStandards and Technology officials plan to phase out a widely usedcryptographic hash function known as SHA-1 in favor of larger andstronger hash functions such as SHA-256 and SHA-512.

A little further down William Blurr, a NIST security guru is quoted:

"There’s really no emergency here," Burr said. "But you should beplanning how you’re going to transition — whether you’re a vendor or auser — so that you can do better cryptography by the next decade."

So are we suprised by what appeared on Schneier’s Blog yesterday:

SHA-1 has been broken. Not a reduced-round version. Not a simplified version. The real thing.

The research team of Xiaoyun Wang, Yiqun Lisa Yin, and Hongbo Yu(mostly from Shandong University in China) have been quietlycirculating a paper announcing their results:

  • collisions in the the full SHA-1 in 2**69 hash operations, muchless than the brute-force attack of 2**80 operations based on the hashlength.
  • collisions in SHA-0 in 2**39 operations.
  • collisions in 58-round SHA-1 in 2**33 operations.

This attack builds on previous attacks on SHA-0 and SHA-1, and is amajor, major cryptanalytic result. It pretty much puts a bullet intoSHA-1 as a hash function for digital signatures (although it doesn’taffect applications such as HMAC where collisions aren’t important).

The paper isn’t generally available yet. At this point I can’t tellif the attack is real, but the paper looks good and this is a reputableresearch team.

More details when I have them.

The combination of the two messages makes one wonder doesn’t it.

Anyway, my main worry about all this has to do with DNSSEC that uses RSA/SHA1 based signatures.

I am not a cryptanalist and I confess I know far less than I would like to know on this subject but I figure that given the pre-defined structure of the material being hashed (a RRset wich contains well defined fields that can only have well defined vallues such as type codes) an exploit would take more than 2^33 ops. I need education… How many orders of magnitude does one gain by needing structure?

Sisi and Sissy boys

Sisi and Sissy boys



About a week ago I was invited to attend the musical “Elisabeth” in the the “Theater an der Wien“.This was the second time I attended a musical show. And although Iappreciate obviously high production quality (hydrolic platforms,costume changes every other minute, &c, &c) I just do not enjoythe music. Again it has a high production quality but for some reason Musicals do not appeal to me that much. Is it because of the cliches? Idon’t know, rock-n-roll is full of 3-chord cliches. Is it the lackof irony? That could well be, because there is one musical, which I have never seen, butlistened to many many times and that is full of irony. “Thing Fish”.

So what about this topic title… Sisi and Sissy boys.

Well as you all known “Elisabeth” Empress of Austria – Queen of Hungary was called “Sisi”. And the first line in “Thing Fish” is:

Once upon a time, musta been ’round October, fewyears back, in one o’ dose TOP SECRET LAB-MOTORIES de gubbnint keep stashed away underneathVirginia, an EVIL PRINCE, occasion’ly employed asa part-time THEATRICAL CRITICIZER set to woikin’on a plot fo de systematic GENOCIDICALREMOVE’LANCE of all unwanted highly-rhythmicindividj’lls an’ sissy-boys!

Back to listening to the hilaric adventures of our EVIL PRINCE, Ronda, Harry and Sister OB’DEWLLA ‘X.

Presidential Homograph ban

GrumpOps wrote:

Bush Promises Ban on Homographs [Permalink]

Fri Feb 11 19:46:18 EST 2005
Category [Internet Politics]

WASHINGTON, DC – In a press conference today, White House PressSecretary Scott McClellan stated that President Bush would renewattempts to institute a Constitutional amendment banning homographs.Citing recent security concerns over homographs,McClellan noted, "These homographs are more menacing than ever before.It is no longer a localized affair. Through the process ofinternationalization, they are now organized into different kinds ofgroups that make it harder for us to recognize."

Many security experts have called for the tagging ofhomographs, expressing the need for visual indicators when homographsare present. However, civil libertarians vehemently disagree, arguingthat such actions smack of the ages-old ignorance and prejudiceregarding unfamiliar, foreign characters.

So I asked GrumpOps for a reference… and Grumpops replied:

That was satire

Ouch… I honestly believed this. Does that say more about me than about the President of the USA?


Senor Coconut y Son Conjunto

Since I bought an Ipod I’ve been going retro.

I started listening to things I first bought when I was a teenager suchas “I am” by Earth Wind and Fire, “Out of the Blue” by Electric LightOrchestra and Kraftwerk’s “Computer World”.

That last album contains one track that remains appealing; “ComputerLove”. I still do not understand why. The tune is overproduced,too simple and cliche but it manages to tickle the lower belly. I ampuzzled.

Recently somebody told me that Senor Coconut y Son Conjunto did a whole album with Kraftwerk covers.

Google brings us to an article that describes some of the background

Although the disc is credited to Senor Coconut y Son Conjunto, it’s purely the work of Schmidt on keyboards and samplers, helped by three vocalists. And he’s fully aware of the irony involved in what he’s doing, noting that “since the entire album is programmed and not played by real musicians, it contains the simulation aspect and questions the term of authenticity.” At the heart of the music, though, he “tried to interpret their songs trying to imagine how a real Latin band would do them. The Latin styles I worked with are certainly uplifting and light” and form an wonderfully absurd juxtaposition with what Coconut called “the Kraftwerkian coolness.”

Do I like “Coconut”? I am not sure yet. I need to listen to it a little more to appreciate if it is more than a gimmick.