a few days ago, we happened to be in berlin for a few hours. we did a small touristy tour and visited some famous places. here are some impressions.

railway, power and memory.

we started at the central railway station, crossed the spree and walked up to the german chancellery and the reichstag, and continued to the holocaust memorial.

global stone project.

after that, we continued into the direction of the tiergarten and found the global stone project.

tiergarten, composers and the soviet war memorial.

we continued through the tiergarten, were we saw, among a lot of beautiful nature, a memorial for beethoven, haydn and mozart and the soviet war memorial.

trash.

besides beautiful nature, the tiergarten also features: trash. both “real” trash, as well as intellectual trash (see the bench’s inscriptions).

the memorial church.

our trip ended at the memorial church, which was bombed during the second world war and not rebuild. unfortunately, they build a modern version of the church right next to it, which blocks the view on the old one and, in my opionion, is not exactly beautiful.

it is also possible to enter the ground floor of the ruins of the old church.

here’s a small “tutorial” on how to make a snow angel:

when you’re done, you can try to leave it without damaging it, get yourself photographed in it, or just have fun in it:

believe me, it’s fun :-)

helsinki.

after the stay in rovaniemi, we took the train back to helsinki and stayed a few days there as well. besides a concert of moonsorrow and korpiklaani, we visited some churches: the uspenski cathedral, the helsingin tuomiokirkko, as well as the temppeliaukio church. we were extremely happy to visit the temppeliaukio church when it was almost empty, which is apparently very unusual.

frozen harbor.

even though it was raining and the snow was melting, there was a lot of ice left in the harbor and rivers. here is a small impression of its beauty:

and here are some more pictures from the harbor area:

the sibelius monument.

we also visited the sibelius monument, a beautiful piece of modern art dedicated to the finnish composer jean sibelius. enjoy some impressions:

in march, we did a trip to finland, mostly to lappland.

riding a train up to rovaniemi.

starting in helsinki, we took a train up to rovaniemi. then, we took a bus to vikajärvi, a small municipal around 30 km north-east of rovaniemi.

staying in vikajärvi.

we stayed in a cottage right next to lake vikajärvi:

we had a lot of very soft, powdery snow there. enjoy some pictures of the cottage and its surroundings:

a night in vikajärvi.

here are some night photos, shot from the cottage to the outside. during daylight time, we never saw any animal, except birds somewhere in the sky. during night, we didn’t saw any animal as well, but we heard treacherous crackle from the surrounding woods and saw tracks of smaller and larger animals in the morning. for these reasons, we never really left the cottage during night.

we also had a good view on the moon:

a short visit to rovaniemi.

after a long stay in the cottage, we spend a few days in rovaniemi. we visited the artikum. the historic train is situated next to the railway station, and the last strange photo is from the lamp in our hotel room.

since i’m always forgetting what to do to encrypt a harddisk, and have to rely on other sites (which might go offline once), i decided to sum everything up in a post. parts can already be found here in this blog.
note that the disk device name can differ from computer to computer, so i used /dev/sdx in this description which you have to change to the right name.

creation.

first, connect the disk and unmount it. then, delete all existing partitions and create a linux primary partition (or do whatever else you want):

$ sudo fdisk /dev/sdx

then it is recommended to clear the partition with random data:

$ sudo dd if=/dev/urandom of=/dev/sdx1

note that this step takes a lot of time.
then, make luks aware of the drive, open it with luks and format it:

$ sudo cryptsetup –verbose –cipher aes-xts-plain64 –key-size 512 –verify-passphrase luksFormat /dev/sdx1
$ sudo cryptsetup luksOpen /dev/sdx1 encrdisk
$ sudo mke2fs -v /dev/mapper/encrdisk
$ sudo cryptsetup luksClose encrdisk

this creates an ext2 file system. now you should be able to unplug the drive and reconnect it, and ubuntu should ask you for a passphrase to unlock the disk. feel free to add -L “label” (at most 16 characters; see the man page for more details); ubuntu will try to mount the disk as /media/label then.

(edit: since there is now a successful attack on the aes-cbc-essiv encryption mentioned here earlier, i changed it to aes-xts-plain64, using a different approach.)

mounting and unmounting.

to mount:

$ sudo cryptsetup luksOpen /dev/sdx1 encrdisk
$ sudo mount /dev/mapper/encrdisk /mnt

to unmount:

$ sudo unmount /mnt
$ sudo cryptsetup luksClose encrdisk

note that for example newer ubuntu versions automatically ask for a passphrase and performs luksOpen / mount / unmount / luksClose for you.

checking.

basically, you just have to open the partition, run the usual file system check, and close it:

$ sudo cryptsetup luksOpen /dev/sdx1 encrdisk
$ sudo fsck -v -C -n /dev/mapper/encrdisk
$ sudo cryptsetup luksClose encrdisk

passphrase management.

note that luks has a storage of several passphrases, which can all be used to open the partition. one can add and remove phrases to/from this list.
to add a passphrase:

$ cryptsetup luksAddKey /dev/sdx1

to remove a passphrase (you have to enter the passphrase to be removed):

$ cryptsetup luksRemoveKey /dev/sdx1

to remove the passphrase from a slot (useful if you forgot one of the passphrases and want to remove it):

$ cryptsetup luksKillSlot /dev/sdx1 0

i just got orphaned land‘s new album, the never ending way of orwarrior, after long years of waiting. it’s amazing! the first track, sapari, is really catchy. i’m pretty much addicted to it. i might write more about the album later, but for now, here’s the official video for sapari:

edit: apparently, century media requested to delete that video and replaced it by another version of the same thing, with a more “hip” title. great. whatever. here’s the new version:

for some reason, they screwed it up that a lot of hyphens appear in the title… whatever…

today, i heard about, downloaded and watched valkaama, a movie released under one of the creative commons licenses. (this means that you can actually download the sources of the movie and make your own version. and, probably more important to most people, you can just copy and watch it without restrictions.) technically speaking, the movie is of good quality, except the audio, maybe. i’ve listened to the movie with headphones, which was a bit annoying since voices were often only audible on the left or the right channel, but almost never somewhere inbetween. on speakers, this is fine, but with headphones it sucks. but besides that, everything’s great. so go and watch it, but maybe not with headphones :-) the movie also features inarijärvi, one of the largest european lakes, located in northern lapland.

after attending the joint mathematics meetings in san francisco, i want to share two points you should not try to copy when you’re organizing a conference.

• in case you have a lot of parallel sessions, try to schedule sessions with similar topics in parallel. this minimizes the number of days people from these areas have to attend the conference.
• promise wireless internet, but do not provide a backbone which can handle this. after noticing it is too slow, simply turn it off for the rest of the conference.
• this applies more to conference center owners. do not install power plugs anywhere near to areas where tables and seats are placed. and by any means, never install power plugs in rooms where talks are held.

people will really appreciate this and regard your conference as one of the best ever.

for new year’s eve, we traveled to oldenburg. on the way back and forth, we saw some interesting things in osnabrück. finally, on the way to dresden, we saw a historic train of the deutsche reichsbahn in leipzig. here are some impressions.

osnabrück, covered in snow.

new year’s eve.

osnabrück, outside the train station.

a historic train in leipzig.

on christmas, my girlfriend and i visited lüdinghausen, my home town. we visited two castles, burg lüdinghausen and burg vischering, and my old school, the st. antonius gymnasium. here are some impressions.

location.

they are all located relatively near to each other, as the map here shows.

the first castle: burg lüdinghausen.

my old school: the st. antonius gymnasium.

the second castle: burg vischering.

in case you wonder: the right photo in the second row depicts a pranger. one can actually try out this one :)