One big attack vector would probably be the most obvious. Physical access. Until you are not living in a bunker and depending on the amount you store this would be an efficient attack vector.
Since your plan does not mention any backups a "simple theft" of your harddrive would be an option.
Another way to gain access over your private keys is to infect your pc which is connected with the internet.
If you have a big amount stored and an attacker is targeting at you it probably wouldn't be that hard to get malware on your pc which will infect the usb stick.
And once USB is infected and you plug it into your cold pc to sign the TX the private keys could be copied over to the usb without you noticing it.
And the next time you connect it to a pc with internet connection (e.g. when you want to push the TX) the malware automatically pushes a TX of all your coins to his address even before you can start pushing your TX.

Of course this is more theoretical nature. But its definetly possible. Noone would put so much effort into it for 1-2 coins.
But 100 BTC are pretty attractive. Big Big Holders should definetly be careful about giving too much personal information away.

In fact there aren't too much reports about hacked mobile wallets. I think the majority of all BTC owners dont have big amounts on their hot wallets.
This leads to a low potential amount an attacker could steal. In addition to that mobile wallets usually dont have more security issues than standard desktop wallets.
And its a lot easier to get malware spread around windows user with new exploits poping up every day than to spread it through the app store.
An attacker (who is looking to profit) is probably going for the (slightly) easier and (obviously) more profitable way, targeting desktop user.

Unfortunately i dont know anything about the UK version of this App. Therefore i cant give you detailed information.
But the Ledger app has not been taken off the Appstore in other countries as far as i know.



You could either search for the App online and verify signature after downloading it (to be sure you have the original, and not modified, version).
Or you use your security card which should be delivered with your Nano.
If there is no security card this probably means you bought your Nano from a non-official seller?
If thats the case i would not use this Wallet.. cant be sure if you got a manipulated firmware.

But if you just lost your security card i think there is a tool which you can download which creates a new security card based on your ledger nano.

Your idea of a offline Raspberry Pi works. If you are completely offline (and also via cable, not WiFi) signing Transactions and relaying them to your online PC.
But in terms of usability.. i would recommend you a hardware wallet.
There are quite a few on the market which can hold different Cryptocurrencies.
And for a few (which cant be hold by HW wallets, because of too less of adoption) you can use your offline RASP.
The RASP is definetly more "complex to use" and not that "error forgiving" as a hardware wallet (e.g. trezor or ledger)

Yes, electrum will always be able to creates a new address. Electrum generates a seed from which tons of addresses can be made of.


Addresses created are random. They are not unique "for sure". But the possibility of finding a private key, someone else already found are almost 0.
Meaning if every PC on this planet would create addresses 24/7.. there probably wouldnt be a collision until whole mankind dies. (Including Birthay paradox)


Theoretically you dont have to worry. But the earlier its in your offline generated wallet.. the faster its in a "safe place".
If you are using Windows and you are browsing / reading mails on your PC.. its probably not a good idea to keep them in a normal wallet on your desktop.

Open a block explorer of your choice (e.g. https://blockchain.info), then search for your "recieve-"address you gave to your curstomer(?).
If you dont find any transactions onto this address, ask your customer to send you the transaction ID.
Afterwards you can check the TX ID on blockchain.info to see if its the right recieving address.
If so, you should additionally check the tx fee and wait until at least 1-3 confirmations until you process his payment.
If your address doesnt show any TX and your customer cant give you a valid TX ID, he is probably trying to scam you.

You should never be storing your coins on a online wallet / exchange.
There is no guarantee coinbase is going to pay you those BTG out.
Coinbase has the control over your private keys (the real bitcoins). You only have an account on their website which gives you "the right" to send coins.
In case of a fork coinbase is in charge of the BTG coins. They may give them to you.. or they dont.
I would recommend to download a wallet for your PC (you can download a light weight wallet e.g. electrum)



Yes, those are all your addresses.
Electrum generates a new address for every transaction (for privacy reasons).
Those are all addresses which you are in control of.

Thats true if you are looking at the security aspect. Noone can steal your banking information or let you visit a phishing site (as long as you use a standard browser which shows https certificates).
But its possible to read out meta data. This means an attacker could theoretically see packets arriving (or being sent; depending on the wpa handshake).
Information like IP-Addresses (Websites visited) and duration of "interacting" with the website can be reviewed by an attacker.

But the KeyReinstallationAttaCK is a targeted Attack, meaning the attacker has to be in your wifi range and he has to be specific aiming at you.

I personally dont think Bitcoin will hit 20k $ (and also i dont think ether will hit 15k).
Bitcoin probably will rise, yes. But not in this dimensions. If bitcoins shows some indication to be able to rise that high that fast.. it probably will get
regulatet/forbidden by governments to make sure there is not too much money out of their control.



In case of nothing unexpected happening (which would destroy BTC completely) i dont see why bitcoin should drop 10 $ in 2 years.

You are probably not the only one with this idea. A lot of people had this thought.
Noone can predict what will happen with BTC / BTG. It can be either a good idea to buy BTC now to recieve BTG.
But on the other hand this could also lead to a loss of capital. It may be the case BTC drops together with BTG and you will either cut your losses
or keep holding until it will recover again to take your investment out.

This, actually, is the only way this works.
Ledger Wallet software does not support sending from specific chosen addresses.
Of course there is quite a big risk contained in exporting/importing your private keys.
Theoretically it shouldn't matter from which address you send. Do you have a reason?

1. Not really, depending on what kind of a criminal you are. Your watch-only wallet communicates with the internet and sends/recieves packages containg your address (httpPOST/GET methods).
If you are communicating via https, its secured. If not and the police is already observing you.. there is a chance they will get proofs you "watched" this address.
In case you are not a big boy criminal.. no.. there is no database or anything which keeps an eye on which ip is observing which address.

2. Yes this works. Your Blockchain doesn't even have to be up to date. Creating unsigned TX's is easy.

3. Yes

If your PC is patched and your router is still vulnerable to this attack then it depends on which device initiates the handshake.
One direction of your data stream can be decrypted (decrypted in terms of WPA2). If you are still encrypting your information with TLS (https) then you are completely safe.
The KRACK attack puts you in a situation comparable with a free wifi hotspot in a public place.
If your PC is clean and you are communicating via https (valid signatures from website provider) you are safe.

Noone can guarantee you to get your Bitcoin Gold if you keep it on an exchange.
Bitcoin Gold will be a different coin (with same block history until block x) as Bitcoin.
If you want to be safe while fork occurs you need to backup your private keys. Since exchanges only "credit you a btc amount to spend" you dont have control over the private keys holding your BTC.
I would strongly recommend to install an offline wallet (a leightweight wallet doesn't need a lot of space e.g. electrum) and move your funds to your wallet.
You will be completely safe when the fork occurs and noone can "steal" your bitcoin gold.

This depends on your plan and on the risks you are willing to take.
Bitcoin is the first crypto currency. It is Bitcoin.
If you want to stay safe then go for BTC and see your money accumulate.
On the other hand if you like to take risks and believe in ethereum then go for it and invest into it.
I would really recommend to read into both of those coins/platforms and then decide based on your new knowledge.
I, personally would invest in both. With the majority of my investment in BTC's.

I think even if he started to move 1 small satoshi from his (watched) addresses.. this will harm the market pretty strong.
I think the best would be if those coins would never be touched by anyone.
If all of those coins would be put on an exchange the price would immediately drop (extremely).

I am pretty sure cryptocurrencies will replace fiat in the near future. I dont think it will be BTC or any other decentralized cryptocurrency.
It probably will be a coin "based on blockchain technology" which wont be decentralized and will be in "full control" from governments/financial institutions.
Like russia started to roll out the Crypto Rubel.. i think a lot of countries will follow soon.
I hope they wont see BTC as a threat to them and start banning it everywhere.

Thats not true at all. As long as you are in control of your private keys (doesnt matter if they have been generated by a core wallet or by any other wallet)
you are fine and can decide for yourself which "chain you follow".
And additionally al ot of wallets provide both chains (e.g. electrum if im not mistaken).

3x3 numbers have a coding power of 10^9 (= 10.000.000.000).
I dont think this is related to a private key/seed anyhow.
Any android mobile could bruteforce those "keys" in a very small time.
Maybe its just a reminder for a password or anything? or for a word? each number = letter in alphabet?

It is possible you will get your BTG from a exchanger.
But there is also the possibility they just wont. The only way to ensure you are really going to get your BTG is to be in control of your private keys.
Since a web wallet only provides you an account on their site with BTC value to spend.
If they want to keep their BTG's, they dont have to give it to you.