How can your identity be compromised with bitcoin?

[manuel]

I have read vague references to possible ways your identity could be compromised with bitcoin but I dont' really understand how it could work.  Can someone give me a link to an explanation or explain?

If you use a different random address for every transaction how can your identity be compromised?

[Sukrim]

You buy at Amazon and enter your shipping address.

You pay to Amazon's address, now Amazon knows that the address you paid from belongs to a guy living in 123 random street.

[manuel]

You buy at Amazon and enter your shipping address.

You pay to Amazon's address, now Amazon knows that the address you paid from belongs to a guy living in 123 random street.

But if you never use that address again how is that useful information? 

If you're talking about ordering something to be delivered to you you have to give up your physical address no matter how you paid for it. 

My point is how does bitcoin compromise your identity?

[Sukrim]

If you do not have the exact amount of BTC to pay Amazon, they now know at least another address with an active balance that 100% belongs to you (the address where the change went), so you either have to launder this or never ever spend it.

I am not sure what you mean by "compromising an identity", could you give an example?

[manuel]

If you do not have the exact amount of BTC to pay Amazon, they now know at least another address with an active balance that 100% belongs to you (the address where the change went), so you either have to launder this or never ever spend it.

I am not sure what you mean by "compromising an identity", could you give an example?

I mean figuring out who you actually are.  Amazon is a bad example because you have to give up your identity anyway.  I am saying how can you find out who somebody is if you never use the same address twice?

[the joint]

Bitcoin is "anonymous" only to the extent that there is never a need to associate an identity with any public address that can be created.

But, Bitcoin is better described as 'pseudonymous' because the lack of an association between identity and public address doesn't mean that much.  In every transaction you make, at least one other person (the person with whom you exchange) will know that you are linked to a specific address unless you go to very significant lengths to mask your identity.  

[franky1]

ok lets say the government have cloned the data on a drugs website. they see that  an anonymous seller that has not listed his home location address but has withdrawn funds to address 1XTr45ecr3tAddr355BlahBlahBlah

the government can simply google search:
1XTr45ecr3tAddr355BlahBlahBlah
 and see where it "might" have been published on a forum, a website, an email that is not Tor protected.. or even in your phone metadata (yes they can search this too)

so if you use the same address linked to other usernames or cellphone data they can get you, or atleast expand on searchable phrases to narrow down on you.

if you then put the funds from the drugs site withdrawal into a known exchange deposit address or an known amazon/retail deposit address. they can try seizing personal Identification from these companies.

the thing about bitcoin is that its your money and your address.. no one is forcing you for information linked to every address you use. so if you hide it well and not link your identity to it you can hide..

just like bank notes. there are not very many places that will ask you for ID so if you avoid using a banknote with a tainted serial number in a place that asks for your ID. no one will know.

[pa]

Because the blockchain stores all transactions, a motivated researcher could analyze the blockchain and determine which addresses appear to be associated and are likely controlled by the same entity. Then if any of the addresses can be assigned to a personal identity, all of the addresses can be so assigned.

These are probabilistic inferences, not "beyond a reasonable doubt."

If CoinJoin becomes widely used, this "network analysis" will become less useful. It can also be foiled by using coin "tumblers" or "mixers," although the use of such tools might appear suspicious to law enforcement agencies.