Newcomer CampBX has an option for shorting bitcoins.
Haven't tried them myself, so can't comment on whether they are any good or not. But they seem to have put some efforts into creating a secure good looking exchange platform.

1. Send contaminated coins with long history to online btc wallet service (OBWS).
2. Create a 1-time Mt. Gox wallet by logging in the deposit page
3. Use 1-time Mt. Gox wallet as the withdrawal address on OBWS
4. You have anonymous bitcoins in your Mt. Gox balance that appear to originate from OBWS with a completely random history.

Or if you want a 1-step program:

1. Mint your own, unused fresh coins by mining. No history, no way of knowing who 'created' them.

In that case. If you have two computers with same wallet and then make 100transations on each computer, they will have different reserved addresses, right? Will that be a problem?

LOL! Missed this post!  
"Send him War and Peace" doesn't mean send him "pattern War and Peace", but broadcast War and Peace, Leo Tolstoy book:

http://en.wikipedia.org/wiki/War_and_Peace

  Sending patterns.. I'm still laughing!!!  

Damn! You're a cute troll 
5 line trojan (with 20 Mb batch of attached DLL's?) 

[removed]@laptop:~$ ps -A | grep bitcoin
 1926 ?        00:40:44 bitcoin
[removed]@laptop:~$ file /proc/1926/fd/* | grep .dat
/proc/1926/fd/11:  symbolic link to `/home/[removed]/.bitcoin/addr.dat'
/proc/1926/fd/12:  symbolic link to `/home/[removed]/.bitcoin/blkindex.dat'
/proc/1926/fd/13:  symbolic link to `/home/[removed]/.bitcoin/database/log.0000000163'
/proc/1926/fd/14:  symbolic link to `/home/[removed]/.bitcoin/wallet.dat'

There's a significant increase in security by moving the file, despite if "some software can scan your computer", as that very same software probably can do whatever it takes no matter what security you imply.
I don't know if you were looking at the code or can reverse engineer software of the latest virus for Bitcoin, this method alone would put them all out of commission... yes in the future a better skilled coder(...); but also in the future machines calculating Petahashes per second(...).

MT, if I could suggest just one thing, it would be to hire a full-time PR person whose only job is to monitor IRC, forums, and email.

Hmmm, me thinking about those nfc enabled smartphones ...

mmmh
 interesting do you mean a thing like hcbi-banking-device?

Depends on what the trojan does.

Still, you believe it doesn't worth 2 lines of code because some other attacks will get through? Then we rather let go computer security all at once, as eventually some kind of attacks will pass... so what's the use?

You give 1MB key for OTP comm with a sub, and rather you not send them any block longer than 1MB, send him War and Peace and you start to get a pattern.

That's an improvement of
http://en.wikipedia.org/wiki/Vigen%C3%A8re_cipher

The indecipherable cipher suffers from patterns, the pathetic attempt done by Gilbert was to create an algorithm where the key matches in size the crypt text. Resulting in a stupidity, as if you can send such key securely, you rather send the plain text the same way and spare you from some worthless work.

Given a long enough key and a short enough text to Vernam's method and you would get that effect already.

PS - This topic isn't about cryptography anyway... my idea just provides a "hiding the wallet" not "encrypt it". -> This means that currently is like if everybody was using their wallets in the back pocket, making life easier to pickpockets. My method would simply make anyone put the wallet wherever he wishes... making pickpockets to have to look for it - still doesn't mean you get rid of pickpockets, just their job gets harder.
 

It's run by a doctorate-level professor who has also been with bitcoin pretty much since the start.

You can find him on the forum under the name NefariusNeferio, he's one of the moderators.

Thanks! I support your initiative.

Wow! I'm impressed! 
Not even PGP or SSL can be considered "unbreakable" - rather really hard to break -, guess you would get a Nobel Prize out of that one.

Right.  Want to buy a Fax Machine ? - I hear they're the hot new tech for forward thinkers like yourself.

GLBSE is not a real exchange.  There is no volume.  It is not regulated by any government organization.  My expectation of receiving payout should my contract become profitable is pretty damn low.  The site owner has a link where you can donate to him lol.  That is not a professional exchange.  What are the qualifications of the person running it?  Who is running it?  Where is it based?  On the about me page it says the following:

"We Are The Market

Buy, sell, raise, lend, borrow, invest, the single market that does it all. Keep your bitcoin in one market, and instantly switch between different assets, currencies, shares, and bonds to take advantage of the largest bitcoin market.

    * Issue shares to raise capital
    * Pay dividends to shareholders
    * Put resolutions to shareholders and get their vote
    * Issue and sell bonds
    * Borrow and lend to the market
    * Make and recieve loan repayments
    * Issue futures contracts
    * Meta-trade on non listed companies (on other exchanges)
    * And trade all of the above with other traders on the market


Start Trading Now!

The exchange is currently under testing, but is being used, you may use at your own risk but be warned,you could lose your shirt ;-)"


That says nothing, except that the person running it is building this as they go and have no idea what they are doing. 


The fact that these are not the first questions people are asking when this site advertises, just shows how naive the bitcoin community is.  Here are some more good questions:

Who holds my deposit?  Who guarantees it?  Are my funds used for operating expenses?  (I bet they are)  Are my funds held in a segregated account?  In what currency?  How is that account being managed to hedge against currency and bitcoin value changes? 



You might not like what I am saying, but to completely write it off is ignorant.  I have a LOT of experience in gambling, trading, and business.  I've seen a lot of bubbles, I've seen people act CRAZY when they come into a lot of money or lose a lot in a short time.  Be smart.  Learn from the mistakes of others.  People behave in repeating patterns, especially in crowds and markets.  Have you studied the history of bubbles?  Might be a good idea.  If you are one of the ones that has come into a lot of money from this, be smart and diversify.  Acknowledge that there is a real chance that bitcoins could go down the toilet and take some of that money and put it into a different type of investment or business.  I'm sure the smart ones have already quietly done that. 

OK enough good advice.  I know most of you will completely write me off as an ignorant whatever you think I am.  Most people have to learn the hard way, that is just how people are. 

Troll, no. Many folks failed to understand the purpose of encryption and confuse it by "security" when all it does it "hide things" - therefore: provides obscurity.

Everyone with coding skills can make a fake client... what's your point with that one?!
I'm talking about implement this in the open source one...

Obscurity is meant to be something just you know, or a specific recipient; cryptography is just one way to do it. But to very end, security is obscurity and the more obscurity you add to it the more security you get; may it be in method or final product.

The worse part in security is to believe it's unbreakable... but that's "a wrong assumption" no matter the methods you used.

Wrong! Cryptography IS NOT security. Cryptography is a WAY to provide you OBSCURITY.
If you believe on security in open air, then just post your password. Better on, why use passwords? Just come, pick an username and wear it up.

A script kiddie normally go by AutoIt scripts and easy to implement code he can pick from the web; hooking into a running process isn't part of it.
This is also NOT the magical bullet that will kill all malicious software, is a way to make it harder to do so less people CAN do it, therefore less people DO IT.

Why make it easy to attack when all it takes is a file open dialog in the client or an argument passed to the bitcoind to make it way harder?

Security IS obscurity. That dogma you stated makes no sense at all. Anything that's open isn't by nature secure; it's just open.

Yes, a trojan may scan your computer... making it dead slow and probably making you try to figure what's going on. But the current way the trojan have all the way open %APPDATA%\Bitcoin\wallet.dat; easy pick virus for any script kiddie.