In fact, I thought of that myself, that my wallet A could have been contaminated before, while computer A was still connected to the internet.
But here's my logic.
Even if computer A was compromised before wallet A was installed, say, even if there was a virus, what could it do?
It could steal my private key, but there's no network to transmit it. Wouldn't I still be safe?
Probably. The worst case scenario would be that the virus managed to create an address that was somehow predictable and your addresses are weakened. I've never heard of any virus that is able to do this though so take that as a hypothetical scenario. If anything, you should be using a Raspberry Pi with Raspbian. Linux are pretty hard to have malware on it, especially if its a computer that you probably wouldn't use. It costs 35 bucks and its easy as hell to setup. I've done it in an hour. |
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Yep mine is - You have reported 133 posts with 95% accuracy
To be honest 95% accuracy is pretty poor when imo I only ever report spam & shitposting, it should be at 100%. I’m not bothered, just saying.
Mine is 98%. While I do report those spam and shitposting, I find it rather meaningless to be reporting them in some sections. The posts might be deceptively constructive while its a serious misinformation. I normally just give them the benefit of doubt and monitor them from time to time. It's a good idea to report them to a moderator if they are doing it too excessively. Do report the obviously offtopic ones and those that are copied. They aren't worthy of a chance.
It has never been possible to see how many of the reports were good or bad or unhandled. Theymos has released it before but its a short list only for those who has reported loads and loads of posts. |
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Certainly. I've seen an increase in the number of newbie accounts with pretty constructive posts all around and I do merit them if I find the posts genuinely interesting or of substance.
It's important to note that a good portion of those are actually people copying posts from other places and passing them off as their own. Check the posts before you merit them and if they're copying, report them to the moderator as well.
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If you've created the wallet before the HD function was introduced with Bitcoin, then you definitely won't be able to use the HD feature right off the bat. Existing wallet can't be converted to HD wallets and you will have to create a new wallet to use it. Steps to create a new HD wallet. 1) Go to %appdata%/Bitcoin. 2) Rename wallet.dat to wallet-old.dat 3) Open Bitcoin Core. 4) Wait for it to load and go to the addresses tab to get an address. Also make a backup. Then shut it down. 5) Rename the new wallet.dat to wallet-HD.dat. 6) Rename wallet-old.dat to wallet.dat 7) Start up Bitcoin Core and send the coins to the address generated with your HD wallet.  Shut it down. 9) Move the old wallet.dat from the folder and rename wallet-hd.dat back to wallet.dat and you would be able to use the HD wallet. |
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They are supposed to be unspent. Bitcoin exists as UTXO (Unspent Transaction Outputs) and they are basically the inputs of your transactions. When you transfer the Bitcoins from Address A to Address B, some UTXOs are spent in Address A and new UTXOs are created in Address B. If its unspent, it simply means that you haven't spent your coins yet.
Blockchain.info isn't holding your coins hostage or anything. If you haven't spent the coins, then it would exist as an unspent output. You can spend them anytime you want. Whoever told you that is wrong.
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Another doubt: why is SHA256 double?
In Bitcoin, when SHA256 is used, its usually hashed twice and thats what we meant. So its basically SHA256(SHA256()) or SHA256D. It's used to primarily prevent the length extension attack[1] for which SHA256 is vulnerable to but not SHA256D. [1] https://en.wikipedia.org/wiki/Length_extension_attack |
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Its unfair, especially for a new comer like me, i always try to write a good post and done some research before i post, but no one gives me merit anyway. If one merit is too hard to earn then how am i gonna get a hundreds to rank up my account? I think merit system should not be given by member of the forum, it should be given only by moderator. Its less spam with this merit system, i do agree.
You aren't going to be earning merits if you were to post something that has been repeated many many times over the thread or you hasn't been constructive to the topic. You do realise you would probably never get the merits if it were to be given by only mods right? The current implementation kind of gives the community their rights to decide what is constructive and what isn't. |
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Ok, if I have understood correctly the ASICs do not implement the cryptographic algorithms but they directly apply a cryptographic function, is it correct?
Yes. Bitcoin ASICs are only designed to hash SHA256 twice and nothing else. The data is fed from a computer. And if in any way the ASICs "contain" the SHA256 (regardless if algorithm or function), is this content symmetrical or asymmetrical?
Sorry, I've made a mistake. It is neither. Asymmetrical and symmetrical are terms that are used with encryption. In Bitcoin, there is neither the encryption or decryption of any information at the protocol level. SHA256 is used for hashing and not for encrypting; SHA256 cannot be reversed to get the original text. |
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Thanks, I sent it to P2SH addresses, since Bitcoin Core 0.16 wasn't out yet. So you're saying that the above raw transaction format works from and to all Bitcoin address types, right?
Bitcoin Core 0.16 is already out: https://bitcoin.org/en/download. Anyways, yup. P2SH addresses has been supported for a very long time and bech32 will work for createrawtransaction as well[1]. It's the same arguments. [1] https://github.com/bitcoin/bitcoin/pull/11167/ |
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If the transaction has appeared in your bech32 address, then its definitely fine. It wouldn't appear if the transaction is invalid.
Bitcoin Core supports bech32 addresses since 0.16.0 and it is definitely possible to use that command to send to bech32 addresses. If you're using an older version, you've probably sent it to a P2SH address and that is completely fine.
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You likely didn't account for the fees. Depending on your transaction size, your fees could be pretty big.
If that's not the case, when did you make the transaction? Bitcoins should be measured in Bitcoin and not in fiat. Did your Bitcoin (not fiat) decrease more than expected? Can you post the transaction ID of the transaction that you have made?
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Satoshi allocated 1m BTC for himself. Was this an instamine via an initial superblock after the genesis block? Did he just ninjamine the initial 1m coins? If it was a superblock can someone point me toward the lines in the code base so I can learn how it was setup?
He didn't allocate any BTC specifically for himself. He was the only one that was mining on the network for sometime and he happened to get loads of BTC from it. What is checkpoint protection in premine?
It wasn't a premine. Everyone else could mine it. Checkpointing was introduced quite a lot later, where others are already mining. |
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If someone was going to Code up a new blockchain to be ASIC resistant, to re democratize mining, would one select X11 as the most likely hashing algorithm?
Same thing happened with scrypt. The main motivation for it is obviously the profit that can be made from developing an ASIC. It isn't cheap to design and build the ASICs. While most coins has strived to be ASIC resistant, many have failed once they take off. Coins like Scrypt utilised the fact that it's memory intensive and it isn't cheap. They won't be ASIC resistant for a long time in that case. Scrypt-N has a dynamic parameter and that makes them the least suitable for ASIC development. |
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1) Is it correct to say that the cryptographic base used by ASICs is the digital signature?
Nope. A digital signature generally means that a signature is generated that can be authenticated to a known key. ASICs do not do anything like that; they perform SHA256 hashes twice on the block header and they result in a hash. 2) Does this mean that encryption is asymmetric?
No. The hashing methods in SHA is symmetric. Sorry, I was wrong about this piece of info. SHA256 is a hashing algorithm and it is neither symmetrical nor asymmetrical. 3) Is the underlying algorithm SHA256 or ECDSA? I also read double SHA256... I think I've gone a little confused  Thanks in advance! C. SHA256D. Its used to hash block header and the hash is considered in the validity of a block (ie. Determine whether it meets the target). ECDSA is used in the transaction signatures itself. Both is used in the protocol but the mining doesn't consist of ECDSA. |
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Just to be sure, did you import the wallet file that you've used to send the stuck transaction? If not, then the problem would be with the missing change address.
Go to Settings>Wallet tab and check the box to enable the coin control feature. Next, go to the send tab and press "Inputs...". Can you see any of the inputs associated with your address?
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I have a question. If someone wanted to overwrite a portion of the Bitcoin blockchain with random data and have it still validate in place of a correct block, would this be computationally difficult/impossible?
Yes. The client have to validate every single thing in the block. Changing any component of the transaction will change the merkle root and in turn the block header. The block hash would be changed completely and as stated above, collisions aren't possible as of now. You can, of course choose to omit that transaction but that would omit the UTXO as well and it would be unspendable. So the question is, "is it practically possible to overwrite those portions of a bitcoin block that currently contain URLs to apparent CP repositories and still have the block validate properly?"
I know to do this to substitute useful data would be practically impossible. But if one is looking to destroy existing data by overwriting it with any other random string that would compute the same hash (could be completely random in place of these URLs), does that then make the exercise within reach from a computational perspective?
Not possible. I doubt everyone would be with this, especially given that it would be considered a censorship (though it isn't morally correct to promote such content IMO). |
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Not only Linux is better OS and safe from any malware and viruses. Linux is not 100% that your machine is safe.
I heard that there is a way that they can hack your Linux remotely so for me Linux is not 100% safe.
The best OS for me and I know your machine is secured is Mac or Apple OS. never heard that they made antivirus to protect from any malware and viruses but i never heard their phone or macbook are infected.
That's quite a bit of a stretch. MacOS is somewhat similar to Linux but there's a stark difference. MacOSx is closed sourced and you simply can't know what Apple is putting into the OS. Malwares and vulnerability on IOS and MacOSX are definitely not uncommon. MacOSX has been much more vulnerable than Linux in terms of the bugs and exploits. The way Linux is designed limits the effectiveness of most malwares. MacOSX has many antiviruses software out there. I believe that this OS will be 99% safe for any malware and viruses. So if you wanted to save your bitcoin for a long time Mac OS or iPhone is a place where you can feel safe.
Doubt: https://nakedsecurity.sophos.com/2017/06/15/more-mac-ransomware-666-and-7-days-to-pay/However, you can be still safe in linux or windows just always make sure that you add a password and change them every week or month to keep your wallet safe. Just like what I'm doing with my electrum wallet,
You can have a 64 character password but you would still get your wallet drained if you have a malware. |
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I got ripped off from using Green Wallet.
I've had a similar experience. As always, good concept, poor execution. 1). Giving the fact that I lost my bitcoin (being stuck in GreenWallet with no Mnemonic password). High fees on breadwallet, I now contemplate in making payment directly from my HW wallet - is it a good pratice ?
As in using your HW wallet to pay for things online? Then yes. HW wallets are designed to isolate the private key from the computer and effectively shutting that out as an attack vector. A transaction from your HW wallet is no different from another transaction initiated from any other wallets. You might want to take some precautions; always double check the sending address and amount. 2). What about using the Bitcoin core node wallet ? I've been running a bitcoin core node, but I haven't gotten time to learn blockchain basic programming. I could create a wallet on my bitcoin blockchain node. But I read some where, that it's not good practice to run my bitcoins wallet on bitcoin node for security reason, until I become sufficient in blockchain programming...
Programming your own wallet is just a huge waste of time. There are enough wallets out there for you to use. Programming your own wallet just increases the chances of you messing up. Whoever you're getting your sources from, they're wrong. You really can't mess up using Bitcoin Core interface. Unless you go around messing with the raw transactions, private keys etc. |
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I didn't say that. It is not possible to prevent against double spending since it doesn't violate any of the protocol rules. You have to quote my entire post to understand what I'm referring to. Anyhow, I've re-read your posts again and I've understood that your point is that someone can effectively execute a 51% attack if no one else is mining. The probability of anyone executing that is close to zero. One would have to have a significant hashpower before they can even mine a block. Depending on how many blocks ago that is, the cost of such an attack would outweigh the benefits. The effort/resources needed to execute said attack is the same. |
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