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Jonasfj.dk/Blog
A blog by Jonas Finnemann Jensen
January 9, 2008 If Birthday(): Year++; //Oh no I’m 20…
Well, it happened I’m no longer a teenager, that means I just turned twenty. Unfortunately I guess it’ll also mean that I have to stop always saying what I don’t mean, and start saying what I do mean. No more useless, pointless and weird statements in the interest of a good/funny discussion of a dead topic; nope from now on it’ll just be dead discussions. Everything is serious when you not a teenager anymore, I just realized this morning when I woke… 🙂
Well, apart from the getting more serious less teenager thing, it’s also this year I’m going move away from home, at least it’s my plan to study computer science next year (meaning after summer). With regards to my birthday presents they were all move-away-from-home-stuff, pots and pans you know… But it’s pretty much what I’ve wanted too, though chance are I’m going to stave anyway when moving away from home…
December 29, 2007 SimpleECDSA, a simple implementation of ECDSA in C
2 weeks ago I did a school project on ECDSA (Elliptic Curve Digital Signature Algorithm). At HTX we have to do a project that goes beyond the curriculum, we must combine two subjects and do an individual project about something we find interesting. I decided to combine mathematics and programming in a project about ECDSA. Personally I think it was great fun, but perhaps I have a twisted sense of humor 🙂
Anyway, I’ve publish my report here, it’s in Danish though. But I did also write an implementation of ECDSA in C. The implementation is called SimpleECDSA, though I must admit it not very Simple anymore. It uses GMP as integer library, and uses the standardized curves cryptographic operations.
The comments in my source is in English, though I did translate them to Danish, before delivering my paper. Anyway, I still have the source with English comments, so I thought I’d post the source here.
As I had a little spare time this holiday I’ve configured the source with the GNU build system. It my first tarball created with Autotools, and it’s mostly hacked together of snippets from the automake and autoconf manual. But it works and the package compiles, and “./configure” complains if GMP isn’t present. I did also manage to get “make check” to run my internal tests, so I think it’s pretty good, considering the fact that is my first package build with autotools.
If you’ve any comments, bug-reports or questions to my packaging or SimpleECDSA, feel free to leave a comment. SimpleECDSA is ofcourse released under GNU GPLv3, and can be downloaded here:
December 18, 2007 ECDSA: Elliptic Curve Digital Signature Algorithm
I den sidste uges tid har jeg skrevet studieretningsprojekt, og som overskriften afslører har jeg skrevet om Elliptic Curve Digital Signature Algorithm (ECDSA). Jeg har i projektet arbejdet med de matematiske aspekter af ECDSA, og har faktisk gennemgået alle de nødvendige algoritmer. Derudover har jeg selvfølgelig implementeret dem i C. Faktisk gik implementeringen hen og blev en hel implementering af ECDSA. Implementeringen hedder SimpleECDSA, og er skrevet oven på GMP, den er selvfølgelig også frigivet under GNU GPLv3.
Jeg synes selv projektet har været meget sjovt. Der er ikke ofte man får lov til at dykke så dybt ned i et emne. Nu har matematik niveauet i det jeg har arbejdet med så også været så højt at det til tider var direkte underholdende. Okay, måske jeg har en mærkelig form for humor. Men jeg synes nu alligevel det har været sjovt at lege med abstrakt algebra og algoritmer. Og efter dette projekt er jeg bestemt mere sikker på at jeg gerne vil studere datalogi næste år.
Hvis nogen skulle have lyst til at lære ECDSA eller implementere ECDSA, vil jeg mene at min rapport burde kunne danne grundlag for en praktisk implementering af ECDSA. Hvis ikke er der i hvert fald kildehenvisninger nok. Min rapport er skrevet på dansk i LaTeX og frigivet under CreativeCommons Attribution-Noncommercial-Share Alike 2.5. Både rapport og kildekode er selvfølgelig tilgængelig her:
Mod alt sandsynlighed er alle kommentarerne i min kildekode faktisk på dansk. Funktions navne og variabler er dog på engelsk. Først skrev jeg faktisk også alle kommentarerne på engelsk, men da det var et projekt på dansk valgte jeg alligevel at oversætte dem alle sammen, og der er faktisk rigtig mange. Mon ikke også jeg skriver en engelsk post om projektet og poster kildekoden med engelsk kommentarer der. Min viden om C er godt nok begrænset, men man er velkommen til at skrive en mail eller kommentar, hvis man har problemer med programmet, eller mod alt sandsynlighed skulle finde ud af at bruge den til noget fornuftigt.
September 15, 2007 First final OS X release, version 1.1.1
I’m happy to announce that we’ve finally ported the bugfix from the 1.1.1 release to OS X. As reported earlier all prior version of TheLastRipper are broken, due to minor changes on the serverside. This means that we haven’t had a working OS X version for about 2 weeks, the Windows and Linux versions were patched within 3 days, but since we don’t really have an OS X developers on the team this took a while longer. Anyway, it should work now, we’ve also added menu entries linking to the help pages on our wiki. Our beta was close, but not all done, now we think that we’ve got a fairly stable and feature complete version for OS X, therefore this release will be known as TheLastRipper for OS X version 1.1.1, yes it’s final not a beta.
September 13, 2007 Nummer 7507
I dag var jeg til forsvarets dag, efter at have udsat den sådan at jeg ikke kunne komme til at “afsone” før HTX var afsluttet. Det hele var faktisk meget fredeligt. Vi blev hilst velkommen, blev råbt op og fik udleveret et navneskilt. Dernæst så vi en film om forsvaret i dag, noget pladder om at det danske forsvars primære opgave er at stille 2.000 mand tilrådighed for internationale operationer. Herefter skulle vi løse nogle opgaver, en times skriftlige test, jeg tror personligt at man skulle have øvet sig hvis man ville dumpe, testen var meget let. Selvfølgelig kunne den fine mand sige at ingen kunne løse alle opgaver på den givne tid, men dette var da også kun fordi at de sidste opgaver var tilnærmelsesvis umulige at løse. Efter testen så vi endnu en film, – ja, alle kan deltage i forsvarets dag programmet er jo idotsikker; denne film handlede om de forskellige værn hvor man kan “afsone” en eventuel værnepligt.
Da vi var færdige med alt dette skulle vi til forundersøgelse, tjek hørelse og syn, og derefter til lægeundersøgelse, blive målt og vejet – tjek BMI. Sidst men ikke mindst kom jeg ind til session, der får man selvfølgelig at vide at man er egnet, og skal trækket et nummer mellem 0 og 35.000. Alt i intervallet 0-5000 skal aftjene værnepligt, intervallet 5.000-10.000 skal måske aftjene værnepligt, mens 10.000 til 35.000 ikke skal aftjene værnepligt. Som du nok har gættet af overskriften trak jeg nummer 7507, så om jeg skal aftjene værnepligt får jeg først at vide til april, og det afhænger af hvor mange der melder sig frivilligt.
Personligt har jeg ingen intentioner om at aftjene værnepligt, jeg kan godt finde på noget mere fornuftigt at spilde et potentielt studie år på, f.eks. studier! Hvis jeg skal ind vil jeg kraftigt overveje militærnægtertjeneste som et fornuftigt alternativ. Orden, disciplin, råb, mudder og våben er ikke lige min kop te.
September 5, 2007 Last.fm protocol version 1.2, unofficial documentation
As I promised a few days ago I’m releasing the unofficial Last.fm documentation that I’ve been developing in cooperation with Tobias Brennecke (tburny) and Matt Brown (blueboxed), two other Last.fm users. This new protocol for last.fm is very interesting, it offers a small playlist instead of one long audio stream, this is nice since metadata is included in this playlist. The unofficial documentation is available from TheLastRipper wiki, here. All the operations should be possible to do with Firefox.
Anyone familiar with the old protocol (version 1.1) knows that Last.fm gave you an mp3 stream, and a place to go if you wanted to request the metadata associated with the music currently playing. This wasn’t very nice, because you had to guess when a new song started, I know that the last metadata response contained information about how long the song was, but you didn’t know exactly when the song was started. Alternatively it was possible to search the stream for mp3 headers, which gave you precise information about when a new song started. But that required some computing. The new protocol just returns an XSPF playlist with mp3s and metadata, now that is very nice.
September 3, 2007 All prior versions of TheLastRipper broken!
I regret to annonce that all current prior versions of TheLastRipper are broken. It seams that Last.fm dropped support for had a bug in their 1.1 protocol, this weekend. All streams optained from this protocol returns “HTTP/1.0 667 Not enough content left to play this station”. I think it’s a shame, considering the amount of opensource audio players out there with playback support for Last.fm version 1.1. Since all of these audio players, including TheLastRipper have been broken.
Nevertheless, I and some other last.fm users have developed an unofficial documentation of the new last.fm protocol version 1.2. I’ll release it shortly, and I’d expect a implementation of this new protocol for TheLastRipper to start rather shortly too. If you want to stay updated on this issue, you can subscribe to issue 63. You do that by clicking on the star.
UPDATE:
Last.fm didn’t drop support for 1.1 protocol it was just gone for the weekend + Monday. Though a minor change in the login scheme caused TheLastRipper to freeze, this issue have now been fixed, and latest release of TheLastRipper works (Version 1.1.1). We’ll still be working on an opensource implementation of the Last.fm 1.2 protocol.
August 30, 2007 Volume normalization with Amarok
Some users of TheLastRipper has requested integrated volume nomalization (Issue 61). While I admit that I’ve noticed the volume changes between tracks, I’ve never really bordered to find a solution. But since others had similar issues, I decided to take a look at it. I ended up looking at ReplayGain, a project that aims to add a tag, containing volume information, to all songs. Then read the tag at playback and determine the volume. Though the value of the tag must be calculated first.
As this seams like a big feature, and as argued by Andreas in the issue tread, it’s probably not a feature for TheLastRipper. Nevertheless it doesn’t mean that the problem should be fixed, just that it should be done elsewhere. This is also good, since you entire music collection doesn’t necessarily origin from TheLastRipper. The solution is to implement this feature at playback level, meaning in your audio player.
For those of us running Ubuntu and using Amarok, this can be done easily. First open Amarok, choose “script-management”, Click download new scripts. This will open a dialog showing the newest, most popular and most downloaded script for Amarok. Just install the script called ReplayGain. Once this is installed you’ll have to install some dependencies with Synaptic. I’ll try to list those I think is needed: python-kde3, mp3gain, vorbisgain, flac, python-xml
If you enter the script-management in Amarok again, you can enable the ReplayGain script. Enable it, select it and click “Settings”, you can tweak the ReplayGain script a little here. Once your done with that leave the settings, and ReplayGain will print a small popup, telling you which optional dependencies you are missing. I’ve probably forgot to list some of them, you may find them in Synaptic if you think you need them. Though I haven’t found “aacgain” or “replaygain” in the Ubuntu repositories.
Well, you don’t need “replaygain” or “AACGain”, unless you, like me, have AAC music. Actually I’ve just bought my first AAC music from iTunes. I haven’t used iTunes before, but I thought I’d give it a try since they started releasing DRM-free content. So I installed iTunes in my virtual machine, and copied the AAC files back to my Ubuntu system after they were downloaded. First I must say, the quality of iTunes plus files are very good, and the files has ID3v2 tags (other mp3’s I’ve bought online did!). It’s sad that iTunes doesn’t run on Linux, Apple could at least offer a web interface for iTunes plus.
Well, if you have AAC encoded music, you’ll need AACGain, it’s not in Ubuntu or Debian repositories. Actually I couldn’t find any .deb packages for it anywhere. So I decided to make my own. You may download my ACCGain package here. Feel free to contact me if you want the source package.
Once you’re done installing dependencies, and have enabled the ReplayGain Amarok script, you can right click in your playlist and choose “Apply Replaygain tags”, I selected “To entire collection using album tags” it took a while but the volume was automatically determined by Amarok afterwards.
August 19, 2007 Release of TheLastRipper 1.1.0 for Windows and Linux
Like I wrote yesterday, a release of TheLastRipper have been in the workings for a while. Now the final details have finally been solved and I’ve released TheLastRipper for both Linux and Windows. Among some of the most interesting changes are:
- ID3v2 support (
Issue 5)
- International characters (
Issue 4)
- Perfect clipping of songs (
Issue 6)
- Fix tab-index and improve UI (
Issue 41)
- Handle exceptions when launching browser on windows (
Issue 45)
- General exception handling dialog (
Issue 46)
- Support for http proxies (
Issue 44)
- Better overall stability
You may download the new release of TheLastRipper from our project page now!
August 18, 2007 TheLastRipper 0.9 Beta for Mac OS X, with Cocoa interface!
A new release of TheLastRipper have been in the workings for a while and now it just about to be done. Among some of the new features are:
- Perfect clipping of songs
- ID3v2 tag
- Support for proxy settings
- Better threading
- International character support
- Many minor bugfixes
These features have been under development for a while and the Windows and Linux clients in SVN already have these features, they will be release as 1.1 very soon too. But last weekend me (Jonas) and Rene of TheLastRipper developer team, decided that it was time to get a beautiful port for OS X. So we started out with the 1.1 codebase from SVN and installed XCode, Mono and CSharpXcodePlugin on a Mac. Then we wrote one of those simple “hallo world” applications in Cocoa#, after becoming a little familiar with Interface Builder and Cocoa#, we started the development of a client using Cocoa#.
And even though the Cocoa# bindings aren’t complete, the weird behaviour of Interface Builder, minor bugs in Xcode and the fact that we wrote most of it during a hangover, the result compiles (sometimes), and works fine too. This version is now being released as TheLastRipper for Mac version 0.9 Beta, once it’s been tested a little more and the last details have been fixed it will be released as stable too.
Now a bit about Mac and Mono based development. First of I’d like to say that I’m not a Mac user and never have been, I’m a Linux user with years of Windows experience, now practiced in a virtual machine for legacy applications. Now getting CSharpXcodePlugin installed and doing the LetterCounter video tutorial is definitively a good start. But it’s difficult to find documentation for Cocoa#, I had to go with what I could get from the assembly cocoa-sharp.dll using Monodocer. The result was that we copied the cocoa-sharp.dll to Windows and added it as reference to a SharpDevelop project to enable intelliSense, since that was basicly all the documentation we could find. But once that was done, developing the actual code on Windows and the interface on OS X was actually pretty easy. Especially with TheLastRipper since all the logic is in a platform independent .dll, which means we only had to write a little clue code. Of course you need to get hang of how Cocoa and Interface Builder works, but once you’ve got that, it’s certainly possible to work with… Even though Mono on Mac isn’t as easy as it is on Windows or Linux.
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