Last night, Valve released a surprise update to their cult hit, Portal.

Under normal circumstances, an update to a two year-old game would probably not be worth noting. However, these are far from normal circumstances. The last piece of Portal-related news we saw was a minor update in June 2009. Due to its nature as a single-player puzzle adventure, Portal probably enjoyed the peak of its success and internet popularity during its first few months, while we were all telling each other the baked confections were false, that our endeavours were a success. In other words, it's been a while.

The text accompanying the update doesn't mention bug fixes, issue resolutions, or even hint at new content:

"Changed radio transmission frequency to comply with federal and state spectrum management regulations"

Oh really? How could any fan and internet-sleuth not immediately jump into the game, and see what Valve's playing at?

Completionists would notice very quickly that a new, description-less achivement, "Transmission Received", has been added. Astute observers would also pick up on the radio, a small prop sitting in your cell at the beginning of the game, which now features a red light. Grabbing it, one might discover that bringing it with you to the next room causes the light to turn green.

26 such radios have been added in total, and on repositioning each one, the player is rewarded with a short burst of static. Inside some of those noises, and this is where things really start to get cryptic, is a piece of morse code. Minutes after the update hits, and the Steam forums are rife with speculation. Before anyone announces they've secured the full achievement, someone has extracted the new sound assets from the game's content files.

dinosaur01.wav through to dinosaur26.wav, with 1, 5, 12, and 17 featuring morse code. An hour later, and they're decoded:

#1 - Dinosaur 1
=====================================
Interior transmission active
External data line active
Message digest active

#2 - Dinosaur 5
=====================================
9e107d9d372bb6826bd81d3542a419d6

#3 - Dinosaur 12
=====================================
System data dump active
User back up active
Password back up active

#4 - Dinosaur 17
=====================================
BEEP
BEEEEP
BEEP
BEEP
BEEEEP
BEEEEP
BEEEEP
BEEP
BEEEEP
BEEP
BEEP

The second message is googled, and discovered to be an MD5 hash, for the string "The quick brown fox jumps over the lazy dog". The fourth turns out to be double-encoded morse code, and spells "LOL". But what of the rest of the sound files? They sound a lot like... data.

A few attempts at steganography are made, but when one poster announces they've successfully extracted an image from the sound, using an ancient ham-radio image decoding method called SSTV, the thread explodes. It's difficult to make out the whole picture from all the noise, but the Aperture Science logo is clearly visible in the corner.

Individually, none of the images contain any clues about where this is all leading. Several feature letters and numbers, often as close-ups of computer keyboards. The text "BBS" is seen in one. Another has an array of pound-symbols (#), in a format suggesting a phone number. After a collected effort, fuzzy images are eventually clarified, and the lone characters and digits are strung together:

9459C6CAC8C203B8128B7CC63068D4FD

Hexadecimal. The clues from the morse code suggest another MD5 hash. Passing it to any MD5 decrypter site provides the following plaintext:

(425) 822-5251

God bless rainbow tables. Gabe Newell's home phone number? Not quite. Anyone remember what a BBS is? While the younger forumites express their ignorance for how the internet used to work, those with the knowledge of the ancient ways are scrabbling around in their attics for 56k modems. Someone dials in...

GLaDOS login:

Oh, to have been the first person to have seen that flashing cursor prompt! But how to get further? Usernames and passwords from another of Valve's old tease sites, aperturescience.com, don't work. The correct credentials were actually much closer, back in the first message extracted from the morse code. Just a few hours, and hundreds of pages of forum discussion after the original update was announced, the community hits paydirt. Entering "backup/backup" rewards the user with a host of ascii imagery, and message extracts from Aperture Science staff, such as this one:

jsow remind you that Aperture Science is built on three pillars.
Pillar one: Science without results is just witchcraft. Pillar two: Get
results or you're fired. Pillar three: if you suspect a coworker of bein' a
witch, report them immediately. I cannot stress that enough. Witchcraft will
not be tolerated.

So what does it all mean? The BBS MOTD greeting could be a hint:

---- APERTURE LABORATORIES GLaDOS v3.11 ----

3.11? Don't forget Valve are Amercian, and using their backward date format it isn't too much of a leap of logic to suggest it all points towards March 11th, which just happens to coincide with the GDC conference, Valve's next expected public appearance.

I'm not going to be the only one tuning in to the event news that day, eagerly waiting to hear something exciting. Well done, Valve.