Quote from: shorena on December 20, 2014, 12:58:43 PM

Quote from: goldsun on December 19, 2014, 10:08:27 PM

Can't I just install electrum on tails, and save it? So I don't have to get it everytime? I am not sure if I understood your last sentence.

Its possible to modify a live system before you burn it to a DVD, but its probably considered advanced.

Quote from: goldsun on December 19, 2014, 10:08:27 PM

You also talked about multisig, I don't understand what it is. Could you explain it briefly?

Multi-sig as in multiple signatures. Usually there is a single private key that signs a transaction. This signature makes it valid and allows you to spend the funds. This is basically what happens every time you spend bitcoin. You unlock your private key, use it to sign a transaction and broadcast said transaction.
The idea with multi-sig is that you need more than one private key to make a valid transaction. E.g. for escrow services a multi-sig system can be created where the seller (S) has a private key, the buyer (B) has a private key and the person doing the escrow (E) has a private key.
The typical design would be that they all create a single address and every two of them can spend the funds "2 of 3 multi-sig". These addresses would start with 3 instead of 1 like this[2]. The 3 has nothing to do with the amount of keys used. The 3 indicates that its a pay to script address [3] instead of a "normal" pay to pubkey hash address.

On the protocol level bitcoin is "just" signatures, scripts and transactions thus its possible to create an address which funds can be spend if the transaction spending them is signed by 2 of the 3 possible private keys. So in our escrow case, B sends the funds to the address, S sends the goods. If everything is how B expencted it to be B can sign a transaction and pass it to S to sign it as well and the coins are spend (usually to S).
If something goes wrong B and/or S can contact E to decide where the funds should go. Neither B nor S can spend the funds alone, thus E can listen to all arguments and finally make a decision where the funds should be send to by signing the correcsponding transaction.
E.g. OpenBazaar [1] will use this (mostly automated) as part of a mechanism to resolve dispute between B and S.

[1] https://gist.github.com/drwasho/405d51bd1b1a32e38145
[2] donation address for the darkwallet project: https://www.blocktrail.com/BTC/address/31oSGBBNrpCiENH3XMZpiP6GTC4tad4bMy
[3] https://en.bitcoin.it/wiki/Pay_to_script_hash

I see that it's mostly used by 3rd party services right? Like it's not really necessary for me to touch the multisig thing? It seems like bitcoin is simple, but yet it's a bit more complex than what it kinda looks like because it's not just buy and spend/save. It's alot about security.

Seems like I got all my questions answered, it took a bit more than a month. Thank you for taking time answering and explaining all this!