Isn't the debit card already ID:d. I mean. if you pay with your card your ID is already known. No anonymity there 

It is an interesting idea for countries to have their own cryptocoins, but and it is a HUGE but, I do not believe, they would create a currency with a limited amount of coins.

They would probably create a currency that they can dilute the same way that they do the fiat currencies at this moment. And that means the value would be going down. In that regard Bitcoin is much better. 

You need to be root (=admin) to be able to edit hosts file, so it is probably someone who has access to your machine.
I have not heard of any remote malware that can do that. (probably some does exist though.)
Edit: I thought that hosts file exists only in linux, but apparently windows has one too. If you use linux the above comment stands, but not in windows.

Normally when bitcoins are stolen they are difficult to get back, because the thief could be in another country, where your country's law can't touch them.

Good luck in hacking the bitcoin address in my signature.
There is 0.00 bitcoins in it.
For some reason I don't believe hackers will find it very interesting.

In addition to that, bitcoin addresses are impossible to hack 

Wow.

If you are serious, then it would be a good idea to sell enough bitcoins to cover your initial investment. Just to keep your wife happy and the relationship working even if something unexpected would happen to bitcoin value.
Other vice you will be hearing about your "foolishness" for the rest of your life...

You are a brave man with lots of luck

Well at least you are not greedy 

Why not try this address, that has over 1000 000 000$ worth of bitcoins in it:
https://blockchain.info/address/3D2oetdNuZUqQHPJmcMDDHYoqkyNVsFk9r

What prevents you? It is all public knowledge.

There is even a challenge, where you can win hundreds of thousands of dollars if you can break their crypto 
https://www.certicom.com/content/dam/certicom/images/pdfs/challenge-2009.pdf

Good luck!

Bitcoin uses ECC in making the public key from your private key.

Private key is just a big number that is kept secret.
Your private key is multiplied with the base point B using ECC math to get the public key.
Privkey*B=Pubkey

This operation is "one way" meaning that it is easy to do, but almost impossible to reverse.

For some curves like secp256k1 there are some more efficient ways to do the addition and multiplication operations. But basically they do the exact same thing as the "standard formulas" only  ~20-30% faster. For example the field size is  2^256 - 2^32 - 2^9 - 2^8 - 2^7 - 2^6 - 2^4 - 1 which makes it faster to take the mod operation.

The other thing where bitcoin uses ECC is ECDSA https://en.wikipedia.org/wiki/Elliptic_Curve_Digital_Signature_Algorithm
It is a public key signing algorithm, which enables you to verify that you own your address without showing anyone your secret private key. You just use your private key to sign the transfer.

It is really just normal elliptic curve crypto. Nothing that special in it or the curve secp256k1.

What do you mean by a paper backup? Do you have your private key? If you do you can use some light client, which does not require you to download and sync the blockchain, and just import your keys to it.
Eg. Electrum is a good choice.

Once you have your private keys, you can transfer your coins anywhere you want to.

Also. When sweeping you are making a transaction to a new address, and you have to pay a small transaction fee. And it could take a while.

When you import you do not have to pay or wait anything.

Safe when it is not connected to a computer. However, flash drives can get corrupted, so it is better to have at least 2 flash disks.

For added security it is smart to NOT name your file, super_secret_keys.pdf or private_keys.pdf or Bitcoins.pdf or something like that.
But rather name it something that a hacker wouldn't be interested in reading. Examples: "Libreoffice.3.1_manual.pdf" or "Introduction to discrete Maths.pdf". Fo r fun the beginning of the document could actually be just that. Maths or something fun.  
And do not ever mention words like "private key", or "bitcoin" inside the document because those kind of words can be automatically searched from files on the disk...

You could also make the pdf password protected.

Also good to have lots of files on those USB:s to mix things up a little.  

Is this too paranoid?

 

US has strange patent laws. They can patent anything that has not been patented yet. Do you want to patent the wheel?

In civilized countries, you can only patent things that you have invented.
And in addition to that you can only patent things that are not published anywhere  before the patent application has been filled. (even if it is published by you) And you can not patent anything that is not a new INNOVATIVE invention. Meaning that if a specialist of the field thinks that it is "general" knowledge, it cant be patented.

It is also much easier to get a patent in the US. In eg. Europe the patents are examined more throughly beforehand.
In US the real validity of a patent is examined in the court IF anyone decides to challenge the patent. Everywhere else the patent is examined during the patent application process.

In Europe even Satoshi could not patent the blockchain, because it is already published.

MultiSig  uses pay to script protocol.
The private & public keys are not enough. You need to know that it is 2 to 4 address and you also need to have those keys always in the same order for the wallet to be able to create the same address and script. If you change the order it wont work. (I admit that with 4 keys there are not that many possibilities even if you have to guess them  )
Luckily the wallets take care or all the real work, and using them is quite easy.

When I played with multiSig wallet for the first time I did not save everything I would have needed. I created a 2 to 5 multiSig address, then destroyed one key completely (private and public keys) and tried to pay out from the address with the remaining 4 private/public keys. And I could not do it! Even though I had understood that I would only need 2 keys to be able to do it.
To be able to pay out from that address I would have needed the public key from the 5th key too.
If I had made 1 payment from that address all the public keys (and the script)  would have been visible in the blockchain, but I had not, so could not access that address any more.  

It looks like you have saved everything you need to save  
  

You can create a brainwallet in https://www.bitaddress.org/ by selecting the tab "brain wallet"
It will create your address and private key from words or phrases.

I would not recommend it though.
Brainwallets are insecure. Many of them have been hacked.
You might think you are selecting random words, but they probably are not as random as you think, and that helps attaker in cracking your key.

How about using a paper wallet with an encrypted private key?

Then it wouldn't matter if someone copied your paper wallet. Because you can't spend from it without the additional key.

bittaddress.org can make those.

One of the safest ways to store bitcoins is paper wallet(s) with encrypted private key
You can create them eg. in www.bitaddress.org (just do not create them while connected to the internet. You need to download bitaddress to your own machine first.)

With those you will have 2*security. You can store the paper wallets in one place (eg. in a safety deposit box or lawyer?) and have the private keys encrypt keys in another place. For example you can tell that key to your family.
If the encrypt key is long enough it is impossible to use your coins without having both the key and paper wallet.

I do not really get the point of Trezor or other hardware wallets for long time storage. You would still need to save the seed somewhere, probably on paper, and if someone gains access to that paper then they can spend your coins without needing the Trezor.

On the other hand Trezor is very good for a wallet that is in active use. Gives an extra layer of protection, if a hacker has already gained access to your computer...

PS. if you decide to choose multiSig. Be sure to test it first with small sums. Or do the testing in testnet. You have to  be sure you have indeed saved enough data to be able to use your coins.

I have also been wondering, what needs to be saved, when backing up a multiSig address. Clearly just backing up the private & public keys is not enough, because you also need the script.

If you have at least 1 outgoing transaction from your multiSig address, then you do not need to store the script, because it will then be visible in the blockchain. Also the public keys will be visible in the blockchain. so you don't need to save those either, but you will need to be able to copy those from blockchain if you do need them...

But personally I decided to forget multiSig. The reason I was interested in multiSig was increased security, because I thought that to be able to spend from multiSig you would need to have several private keys, and that would make it much safer than normal addresses. And that would protect from someone accidentally generating the same address and using my coins.

Then I found out that multiSig addresses are only as safe as normal addresses with 160 bit security.
An attacker does not even need to find your private keys. He can just try to generate any script that will hash to your multiSig address to be able to spend your coins. (hence the 160 bit security)
And yes. I know it is currently completely impossible, but I was expecting more from multiSig.  

There have been some really good quesses:
https://bitcointalk.org/index.php?topic=507458.0
That pattern makes it possible to know which coins are highly likely Satoshis coins.

For some addresses it is quite easy to know.
addresses 1, 2, 3, 5, 6 have recently been spent from, so they are accessible.

And also 7,8,9,10 have been created in 2013-2014, when bitcoin already had value and those addresses were already so valuable that keys have surely been kept safe.

Address 4 on the other hand is probably lost, because those 79957BTC have not been touched since 2011.

Satoshis untouched addresses DO have about million coins in them, but they are not in one address.

Those coins are in many addresses, each of them holding "only" 50BTC

Satoshi has never moved any of them. except in the beginning on January 2009 to test if everything works properly.