Aim

Centralised exchanges have a history of getting hacked or shutting down making it almost impossible to withdraw your bitcoin. Bitcoin was initially not conceived to be stored in any centralised exchanges.
So it is ideal that you dont take that risk. Instead bitcoin can be easily stored in an address which is generated offline without any internet connection. The steps are as follows
Step 1 : Goto https://www.bitaddress.org Step 2 : Disconnect the internet Step 3 : Move your mouse randomly and add some random keystrokes Step 4 : Click on the print out and take at least 3 printouts of the paper. Step 5 : You get your public key (marked share) and the private key (marked secret) Step 6 : Safe keep your paper in different locations. Step 7 : Withdraw your Bitcoin from the Centralised exchange to your bitcoin address ie public key (marked share) in the print out Step 8 : Check your bitcoin account balance in https://blockexplorer.com/ - After the some few minutes the transaction will appear in the block explorer and you can be sure your bitcoin is transfered to the paper wallet address
How to retrieve the bitcoin from paper wallet
Step 1: Check https://walletscrutiny.com/#tableofwallets Step 2: Decide on a wallet to download Step 3: Check for any recent hacks to the wallet in news feeds Step 4: Import your private key to the wallet. Some wallets may not have the option. Use a wallet with the private key import option ( Example Mycelium Wallet ) https://en.bitcoin.it/wiki/How_to_import_private_keys Step 5 : Use bitcoin whatever is required. And transfer the balance to another paper wallet for safe keeping.
I don't think this is a very secure way to generate a receiving address:
  • if you really must use the website linked in OP, you should do so by saving the site from their github repository, for later offline use.
  • however, disconnecting the internet for a short time will do nothing to defeat malware already present on your machine. It would be trivial for any logging software present to steal your keys once you re-connect to the internet.
  • some printers will store past print jobs in a local memory on the printer. It is better to write down a mnemonic seed phrase using pen and paper as a backup method.
  • looking up your bitcoin address via a clearnet block explorer leaks a lot of data, it is a privacy concern. If you must use a block explorer, use one via the tor network
Another concern: the user REALLY needs to understand how UTXOs and change addresses work in order to safely use a paper wallet. There are many stories of users losing funds after not understanding what they were doing with a paper wallet. User beware!
IMO most people are better off using a phone-based wallet (on a not-jailbroken-phone) to generate an address. Likely better security than the 'old family desktop computer', while still allowing easy backups (mnemonic seed phrase), and easy future access to funds. The user can even delete the wallet app after testing their backup and transferring funds, should they desire discreteness.
reply
i dont use mnemonic seeds BIP-39 for a reason.
  • What i understand is that private keys for mnemonic are derived from the given seed words
  • In my understanding word lists are used from which these words are selected
  • a sufficiently advanced computing device which might come some years down in future may be able to crack the private keys of those addresses generated with mnemonic keys , if these computers are advanced enough to derive all the private keys against all the various permutations and combinations of these 2048 word list like is done in a brute force attack
  • this may be a hypothetical situation but if such a case happens the first accounts to get hacked will be those generated with mnemonic keys
  • on the other hand the private key which is not derived from the mnemonic keys the computing power required to hack may be far higher.
  • as the intend of the OP is to invest and survive such kind of possible attacks for a longer term. i see no rational to go ahead with the easy way of BIP-39 which is why i stick on to my method.
  • I may be wrong in my understandings as i am not an expert in the domain.
if you really must use the website linked in OP, you should do so by saving the site >from their github repository, for later offline use.
Agree there - it is better to save the files from the github repository to the local computer as html files and then run it locally from the computer. This may require a little bit of knowledge there to do that.
however, disconnecting the internet for a short time will do nothing to defeat >malware already present on your machine. It would be trivial for any logging >software present to steal your keys once you re-connect to the internet.
u can format the computer after disconnecting and then generating the printout. this may defeat the malwares. again my knowledge here is limited. or u may use an old computer and then destroy its hard disk after taking the printout.
some printers will store past print jobs in a local memory on the printer.
Thats something i have thought about. Printer can be disconnected from electricity for a while. i am not sure if there is a memory store in any printers where battery is used to store this memory. its unlikely though. again not so sure.
It is better >to write down a mnemonic seed phrase using pen and paper as a >backup method.
Yes. this is a good method to write down. it may work for mnemonic seed words. but for the private key if your writing is exactly not readable and u cannot differentiate between l and 1 , 0 and O , in future when u try to read it. it will be a problem. So if u are using pen and pencil then better write it down and read it again to verify that it is readable
looking up your bitcoin address via a clearnet block explorer leaks a lot of data, it >is a privacy concern. If you must use a block explorer, use one via the tor network
providing the public key in block explorers will not compromise the wallet in anyway because the public key is already exposed to public. Anyone can any time check that. Now if u r worried about exposing ur IP with bitcoin address to a third party website then u may use TOR network
reply
I may be wrong in my understandings as i am not an expert in the domain.
You do misunderstand; the keyspace for a 24 word BIP-39 mnemonic seed phrase is MASSIVE, beyond comprehension. Using a private key that was derived in standalone fashion affords you no additional security. If it did, mnemonic seed phrases would not be common place.
Using a 24-word seed phrase provides 256 bits of entropy, which translates to 2^256 possible seeds. This is an impossibly large number, there is no conceivable way that even an advanced future-computer could iterate through enough addresses to find even one that holds funds. And besides, if such a thing did come to exist, then funds held at BIP-39 derived addresses would be at no higher risk than funds held at any other P2PKH address.
See this stack exchange answer for some example numbers relating to this. In short: it would take an impossibly advanced computer many many many times the age of the universe to find even a single funded key.
Yes. this is a good method to write down. it may work for mnemonic seed words. but for the private key if your writing is exactly not readable and u cannot differentiate between l and 1 , 0 and O , in future when u try to read it. it will be a problem. So if u are using pen and pencil then better write it down and read it again to verify that it is readable
There are various private key formats, but WIF uses base58check encoding to prevent this 'ambiguous character' problem. So that won't be an issue (though correctly transcribing a long string of random characters can be tough itself).
reply
I may be wrong in my understandings as i am not an expert in the domain.
You do misunderstand; the keyspace for a 24 word BIP-39 mnemonic seed >phrase is MASSIVE, beyond comprehension. Using a private key that was derived >in standalone fashion affords you no additional security. If it did, mnemonic seed >phrases would not be common place.
Anything that is easy, would be eventually in common place. The real question is compared to brute force a non derived private key how easy or difficult will it be to crack a derived key.
Using a 24-word seed phrase provides 256 bits of entropy, which translates to >2^256 possible seeds. This is an impossibly large number, there is no >conceivable way that even an advanced future-computer could iterate through >enough addresses to find even one that holds funds. And besides, if such a thing >did come to exist, then funds held at BIP-39 derived addresses would be at no >higher risk than funds held at any other P2PKH address.
See this stack exchange answer for some example numbers relating to this. In >short: it would take an impossibly advanced computer many many many times >the age of the universe to find even a single funded key.
the stackoverflow article is about the difficulty of a regular bitcoin private key. not that of a BIP 39 derived key.
Yes. this is a good method to write down. it may work for mnemonic seed words. but for the private key if your writing is exactly not readable and u cannot differentiate between l and 1 , 0 and O , in future when u try to read it. it will be a problem. So if u are using pen and pencil then better write it down and read it again to verify that it is readable
There are various private key formats, but WIF uses base58check encoding to >prevent this 'ambiguous character' problem. So that won't be an issue (though >correctly transcribing a long string of random characters can be tough itself).
reply
https://www.bitaddress.org поясни почему это безопаснее чем иметь BTC CORE ?
reply
Question asked translated to English as following
  • explain why it is safer than having BTC CORE
Answered in English as follows Because BTC core wallet resides in your harddisk.
  1. Harddisk can crash and you can lose bitcoin, if you dont have backup
  2. Wallet.dat file is digital. it can be sniffed by a malware and uploaded to a server >if you use internet in the computer.
  • Answer Translated to Russian
Потому что основной кошелек BTC находится на вашем жестком диске.
  1. Жесткий диск может выйти из строя, и вы можете потерять биткойны, если >у вас нет резервной копии
  2. Файл Wallet.dat является цифровым. он может быть обнаружен >вредоносным ПО и загружен на сервер, если вы используете Интернет на >компьютере.
Potomu chto osnovnoy koshelek BTC nakhoditsya na vashem zhestkom diske.
  1. Zhestkiy disk mozhet vyyti iz stroya, i vy mozhete poteryat' bitkoyny, yesli u vas >net rezervnoy kopii
  2. Fayl Wallet.dat yavlyayetsya tsifrovym. on mozhet byt' obnaruzhen >vredonosnym PO i zagruzhen na server, yesli vy ispol'zuyete Internet na >komp'yutere.
reply