Confirmed: blockchain.info Shared Coin is broken
So after writing a rather annoyed reply some of us on #bitcoin-wizards tried some test joins, and sure enough it's broken. tl;dr: I was able to easily guess someone's input just by looking at the blockchain data on my first try for a three step mix by just eyeballing the transactions. I've tested this before, and previously Shared Coin was properly matching output value amounts and providing actual privacy - now it's not which makes figuring out where the coins came from trivial. It's a big song and game with all the extra inputs and outputs, yet it's totally useless, and expensive! So tell us blockchain.info, how did this serious bug get intoduced into Shared Coin? A link to the git commits where the bug was intoduced would be helpful.
Finally, a call to action: Dark Wallet is still alpha, and while I trust the intentions of the guys behind it, (I'm their Chief Scientist after all!) I'm not going to be surprised if we find some bugs in the Coin Join. We really need at least one more group working on a Coin Join implementation for the sake of diversity, and preferably not one tied to an inconvenient to use alt-coin.
edit: fix link
http://www.reddit.com/r/Bitcoin/comments/27rsv8/confirmed_blockchaininfo_shared_coin_is_broken/
Just curious what the benefit of these other money tumbling services are over Bitcoin Fog? Are they cheaper or better in some way? Maybe I'm missing out on a better service but I've only used Bitcoin Fog since way back in SR1 days, with the occasional blockchain shared send or shared coin use when dealing with a vendor directly. Are there negatives to it? I've used it a ton and never once had a problem with it. It's always been a very reliable dependable service, never hardly down, not too expensive of fees I feel, and been around a long time so I feel is well established and trustworthy. Just wondering what the reasoning is of those of you who don't use Bitcoin Fog.