Can Bitcoin wallets goes down ?

[OmegaStarScream]

Ty money.investement and what if I run Electrum server what exactly would happen , I was also checking their github and look what I found , does that means that versions from 2.0 to 2.3 was hackable before ? (Check the bold text) *Paranoid*

# Release 2.4
 * Payment to DNS names storing a Bitcoin addresses (OpenAlias) is
   supported directly, without activating a plugin. The verification
   uses DNSSEC.
 * The DNSSEC verification code was rewritten. The previous code,
   which was part of the OpenAlias plugin, is vulnerable and should
   not be trusted (Electrum 2.0 to 2.3).
 * Payment requests can be signed using Bitcoin addresses stored
   in DNS (OpenAlias). The identity of the requestor is verified using
   DNSSEC.
 * Payment requests signed with OpenAlias keys can be shared as
   bitcoin: URIs, if they are simple (a single address-type
   output). The BIP21 URI scheme is extended with 'name', 'sig',
   'time', 'exp'.
 * Arbitrary m-of-n multisig wallets are supported (n<=15).
 * Multisig transactions can be signed with Trezor. When you create
   the multisig wallet, just enter the xpub of your existing Trezor
   wallet.
 * Transaction fees set manually in the GUI are retained, including
   when the user uses the '!' shortcut.
 * New 'email' plugin, that enables sending and receiving payment
   requests by email.
 * The daemon supports Websocket notifications of payments.

[money.investment]

Ty money.investement and what if I run Electrum server what exactly would happen ,

You need to run bitcoind (daemon) / full node for doing public service of running electrum server.

I was also checking their github and look what I found , does that means that versions from 2.0 to 2.3 was hackable before ? (Check the bold text) *Paranoid*

# Release 2.4
 * Payment to DNS names storing a Bitcoin addresses (OpenAlias) is
   supported directly, without activating a plugin. The verification
   uses DNSSEC.
 * The DNSSEC verification code was rewritten. The previous code,
   which was part of the OpenAlias plugin, is vulnerable and should
   not be trusted (Electrum 2.0 to 2.3).
 * Payment ...
 * ...
 * ...

Was only hackable, if you sent payments to domains, using OpenAlias DNS records.

At its most basic, OpenAlias is a TXT DNS record on a FQDN (fully qualified domain name). By combining this with DNS-related technologies we have created an aliasing standard that is extensible for developers, intuitive and familiar for users, and can interoperate with both centralised and decentralised domain systems.

[shorena]

I'am really struggling to find out the solution here , for Bitcoin Core as I said I have issues with it and I'am afraid that my wallet.dat is corrupted or soomething and it eats a lot of CPU & RAM and can't handle that because myPC have only 3GB RAM and that's too low for Bitcoin Core.

3 GB is actually not "too low" for it, my servers runs it fine with only 2GB. I suspect that your overall system is quickly eating up the 3 GB. I dont think this would improve with Win10.

Multibit HD don't have hidden fees AFAIK , they tell you that they will send x satoshi's to the developpers of the application + the fees of the transaction for the miners or whoever takes those .

No the fees are not hidden, but you pay a little to the devs for every TX you create. You have to decide whether this is something you are willing to do or not.

For what comes to Electrum , people just said it's decentralized so how it pass by a server

Its not a single server, but a multitude of servers. Similar to bitcoin core. By default a random server is selected every time you start the wallet.

---

IMHO your best course of action now is

#1 secure your coins, create a backup (if you dont have one already) or a paperwallet (if you prefer)
#2 figure out as best as you can what is actually wrong with your system and whether parts need replacing
#3 test several wallets to find the one that suits you best. MB and Electrum are only the most common ones. There are new wallets you might prefer over these. I think the "choose your wallet page" was already linked, if I am mistaken. here -> https://bitcoin.org/en/choose-your-wallet

[OmegaStarScream]

Look Shorena , I know Paper wallet is the best option probably . but I'am too paranoid (like so much) I was reading this Tutorial on CoinDesk how to make one so I don't make any wrong things I may regret later http://www.coindesk.com/information/paper-wallet-tutorial/

I decided to use this website , I turned the modem off so I'am totally offline and download the Github on their page .I printed then ... I throw the paper . I was too paranoid to find out after 5 years for example that the Adress on that Paper dosen't match the private key . also on Paper wallets should we write the private key by hand ? when we import them to another wallet ?

[Lauda]

Look Shorena , I know Paper wallet is the best option probably . but I'am too paranoid (like so much) I was reading this Tutorial on CoinDesk how to make one so I don't make any wrong things I may regret later http://www.coindesk.com/information/paper-wallet-tutorial/

I decided to use this website , I turned the modem off so I'am totally offline and download the Github on their page .I printed then ... I throw the paper . I was too paranoid to find out after 5 years for example that the Adress on that Paper dosen't match the private key . also on Paper wallets should we write the private key by hand ? when we import them to another wallet ?

I'm pretty convinced that writing is better than copy/paste and printing. I would not be surprised if your printer stored your private key.
Well, I actually did a better (manual method), if you already have been using QT for a while. Using coin control within the wallet itself, I've transferred everything into a single address. I generated its private key, wrote it down a few times and overwrote the wallet.dat 35 times (most secure delete - unnecessary, but since the file is small this is pretty quick). If you're into the design of paper wallets, you could try finding a empty one and printing it.

As stated in the article, there are some security concerns.

[OmegaStarScream]

Look Shorena , I know Paper wallet is the best option probably . but I'am too paranoid (like so much) I was reading this Tutorial on CoinDesk how to make one so I don't make any wrong things I may regret later http://www.coindesk.com/information/paper-wallet-tutorial/

I decided to use this website , I turned the modem off so I'am totally offline and download the Github on their page .I printed then ... I throw the paper . I was too paranoid to find out after 5 years for example that the Adress on that Paper dosen't match the private key . also on Paper wallets should we write the private key by hand ? when we import them to another wallet ?

I'm pretty convinced that writing is better than copy/paste and printing. I would not be surprised if your printer stored your private key.
Well, I actually did a better (manual method), if you already have been using QT for a while. Using coin control within the wallet itself, I've transferred everything into a single address. I generated its private key, wrote it down a few times and overwrote the wallet.dat 35 times (most secure delete - unnecessary, but since the file is small this is pretty quick). If you're into the design of paper wallets, you could try finding a empty one and printing it.

As stated in the article, there are some security concerns.

I hope I'am not annoying anyone here honestly ; Another question and option I may do too which are brainwallets. is this the website where I should do that ? https://brainwallet.org/
All I need to do is a passphrase ? Copy the adress so people send there and that's it ? when I want to send I just need to type the passphrase once again on the website and my Private key should showup then Import it ?? I know I should download it from Github and do it Offline .

What does someone need to crack the wallet basically ? Is it even possible to crack the password if it's hard to guess . People that know me from the internet don't really have much informatinos about me to guess the password and IRL people don't know what Bitcoin is , so it's all about cracking ,how easy or hard is it ?

Also what is "compressed" & "Uncompressed" options

[shorena]

Look Shorena , I know Paper wallet is the best option probably . but I'am too paranoid (like so much) I was reading this Tutorial on CoinDesk how to make one so I don't make any wrong things I may regret later http://www.coindesk.com/information/paper-wallet-tutorial/

I decided to use this website , I turned the modem off so I'am totally offline and download the Github on their page .I printed then ... I throw the paper . I was too paranoid to find out after 5 years for example that the Adress on that Paper dosen't match the private key . also on Paper wallets should we write the private key by hand ? when we import them to another wallet ?

I'm pretty convinced that writing is better than copy/paste and printing. I would not be surprised if your printer stored your private key.
Well, I actually did a better (manual method), if you already have been using QT for a while. Using coin control within the wallet itself, I've transferred everything into a single address. I generated its private key, wrote it down a few times and overwrote the wallet.dat 35 times (most secure delete - unnecessary, but since the file is small this is pretty quick). If you're into the design of paper wallets, you could try finding a empty one and printing it.

As stated in the article, there are some security concerns.

I hope I'am not annoying anyone here honestly ; Another question and option I may do too which are brainwallets. is this the website where I should do that ? https://brainwallet.org/
All I need to do is a passphrase ? Copy the adress so people send there and that's it ? when I want to send I just need to type the passphrase once again on the website and my Private key should showup then Import it ?? I know I should download it from Github and do it Offline.

This is essentially how it works, yes. The biggest concern with brainwallets is that humans are very bad at generating something random and thus many brainwallets are already generated and watched. Dont let that stop you however, just think about it befor you do it. I suggest reading at least this thread by CIYAM -> https://bitcointalk.org/index.php?topic=885616.0

What does someone need to crack the wallet basically ?

Your password/passphrase.

Is it even possible to crack the password if it's hard to guess . People that know me from the internet don't really have much informatinos about me to guess the password and IRL people don't know what Bitcoin is , so it's all about cracking ,how easy or hard is it ?

Also what is "compressed" & "Uncompressed" options

Its hard to say how hard it is without knowing enough about it to make it easy. To give you a general idea of how strong a password can be -> https://blogs.dropbox.com/tech/2012/04/zxcvbn-realistic-password-strength-estimation/

To every private key there is a public key. This public key can either be the full 65 bytes or compressed to 33 bytes. Since the address depends on the public key a compressed public key leads to a different address than an uncompressed one. You need the same private key to spend the coins though. Most are compressed now since it reduced the size of the TX that has to include the public key to allow verification of the signature.

[OmegaStarScream]

I understand how hard it could be to generate such passwords however how that brainwallet website works ? does it generate based on the key or based on the letter & the number written ? because if I use other language (like russian) won't that make it harder to get cracked ?

[shorena]

I understand how hard it could be to generate such passwords however how that brainwallet website works ? does it generate based on the key or based on the letter & the number written ? because if I use other language (like russian) won't that make it harder to get cracked ?

It takes the SHA256 value of your phrase, e.g. SHA256("0") = 5feceb66ffc86f38d952786c6d696c79c2dbc239dd4e91b46729d73a27fb57e9 and uses it as the private key. A private key is a 256-bit number in a certain range[1]. You could use a different algorithm that ends in the same range of possible solutions for a given input or you could even directly generate the private key as a number (in your favorite format). Its just different ways to store the same information. A less common language - which I would argue russian is not - is believed by some to help, but there are pretty scary stories[2].

[1] https://en.bitcoin.it/wiki/Private_key#Range_of_valid_ECDSA_private_keys
[2] http://www.reddit.com/r/Bitcoin/comments/1ptuf3/brain_wallet_disaster/