Obviously, if I run a full node, I can query the copy of the public ledger locally, and my privacy is very strong. Nobody but myself is able to see what addresses I'm interested in.
On the other end of the spectrum, if I let some centralized system (web wallet) hold my keys, then obviously I have given up my privacy.
But what about if I run a SPV client (wallet)? Then the client has to rely on other full nodes in the system to query for addresses. And let's suppose that the nearby nodes are honest and that I'm not concerned with security. But what about privacy? Can it potentially be compromised by say some third party intercepting my queries and collecting a list of my addresses?
In particular, Electrum, as far as I know, is SPV wallet. How strong my privacy is with Electrum?
I've looked into this myself a little bit but i wasn't really able to find anything, I primarily rely on the answers of these users,
Electrum works differently from a lot of other SPV clients. With Electrum, users are required to connect to Electrum servers. The way blockchain.info track the IP transactions is to see who relayed the transaction to them first. If you're using Electrum, the only possible IP address you would see there is the server's. This does not mean that your privacy is preserved; Electrum servers can see all the addresses in your wallet.
neither!
bitcoin transactions do not contain any IP information and blocks in the blockchain contains these transactions. in other words no IP address is recorded.
if by any chance you mean blockchain.info website then the IP address they list is different, it is the IP address of the node that sent them the transaction first. it may be the Electrum node or it may be another node that is just relaying that tx.
regarding privacy and Electrum the only thing that happens is that when you connect to an Electrum node you are asking them for your transaction history so you give them all your addresses which means that node sees all your bitcoin addresses and can connect them together and also record your IP address and associate these two together. whether they do it or not is another discussion.
in other words there are two things here: they see list of all your bitcoin addresses and link them together even if they are not connected + your IP address. you can hide your IP but you can't hide your address list.
As stated above, i'm not sure if this is actually the case, but i'd be slightly worried if it is, since that would imply that there (potentially) really is no such thing as *privacy* while using electrum without a proxy.
It's weird how there's nothing available on this topic, especially if what pooya87 is saying is true. (Think about the information a single node could possibly gather about it's users right?)