19 votes
Accepted

Recovering private key when someone uses the same k twice in ECDSA signatures

Here is a fun thing about ECDSA signatures: you can always replace s with -s (mod N) and the signature is still valid. So when you are deducing the k value, it is possible that someone else flipped ...
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10 votes

How can I find a Bitcoin private key that I saved in a text file?

If you're programming savvy you could write a small program that searches for the regular expression of a Bitcoin private key. Bitcoin private keys have a very specific format: They are 51 keys long, ...
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  • 64.6k
5 votes
Accepted

How does Trezor's wallet recovery work if the private key never leaves the device?

The Trezor generates a seed offline on your device. Neither the private key nor this seed are ever shared with SatoshiLabs. In fact, you're in sole control of your private key: when you first set up ...
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  • 64.6k
5 votes

Recover Bitcoin From Transaction ID

All of the information in the screenshot is publicly available. And no, they won't be useful for recovering your Bitcoin. If you used Electrum, you either need the wallet, the recovery phrase(seeds) ...
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  • 1,255
5 votes
Accepted

Have I lost all my Bitcoin, having sent them to a Bitcoin Cash wallet?

Keys are interchangeable on both chains. If you export the private key of the address you sent it to on the bitcoin cash wallet , and import it back into another wallet (Exodus for Bitcoin?) , you ...
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  • 393
5 votes
Accepted

How can 24 words allow a user to recover a public and private key?

A) For each hierarchical deterministic account path ~2 (if detached) to ~4 (if not detached) billion private keys and associated public addresses can be synthesized. If BIP 44 technology is applied ...
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  • 2,927
5 votes
Accepted

How to derive the private key associated with a Coinbase multi-sig vault address

I did some digging into Coinbase's offline multisig tool to figure out what the user seed actually was and their derivation paths. It turns out the user seed is just that, a seed that is used to get ...
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  • 62.4k
5 votes

How to unlock private key of bitcoin

People with 86 million dollars generally don't need to ask this. People who have been tricked by con-artists are the sort of people that usually ask this. That looks like a "blockchain" ...
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5 votes

How can I recover the missing end of my private key?

TL;DR: You don't need to bruteforce anything here (at least almost), and can recover the missing last 7 characters on an average PC at home within less than 1 second using a simple Python script! In ...
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4 votes

Cannot access my bitcoins because my wallet is still synchronising. What can I do to spend them immediately?

I had to do this for a Dogecoin wallet that was very out of sync once. I will outline the steps that worked for me. My example will be for Bitcoin, though, since that's probably what most people will ...
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  • 13.7k
4 votes

Where can I find code that allows me to calculate Z1 and Z2 from an ECDSA signature?

According to Nils's post, the z values are the hashes that get signed in the ECDSA formula. Background on what data goes into these hashes can be found on the OP_CHECKSIG wiki page and Krzysztof ...
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4 votes

How does Trezor's wallet recovery work if the private key never leaves the device?

The Trezor wallet is a Hierarchical Deterministic wallet. This means that the entire wallet is derived from the seed. The seed is encoded as the 24 word mnemonic which is what you have to backup. To ...
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  • 62.4k
4 votes
Accepted

Can we derive parent’s private key using child’s private key?

But not the former. Can anyone explain what he meant in the former? A child key can refer to two different things: the child private key and the child public key. With just only one of these two ...
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  • 62.4k
4 votes

Can you recover seed words with passphrase on bitcoin node?

Bitcoin Core does not use a seed phrase. Your password is simply the encryption password for the wallet.dat file. No private keys are derived from the password. In order to recover your Bitcoin, you ...
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  • 62.4k
4 votes

Can I recover my own wallet from the public key?

This is impossible. The whole point of public key cryptography is that the public key can be shared with anybody, without compromising the private key. If there were a way to recover the private ...
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4 votes

Recovery after losing wallet.dat and formatting hard disk

Your money is lost without at least one of a backup of important data from the hard disk before it was formatted a backup of the wallet.dat file a note of the private key There is no way to recover ...
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4 votes

Does someone know how to recovery a private key

After some health problem I have lost the private key but I still have the password. If you don't have the wallet file, the password is useless, as the password only encrypts the file. If you don't ...
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3 votes

Cannot access my bitcoins because my wallet is still synchronising. What can I do to spend them immediately?

Open the console on Bitcoin Core. Type dumpprivkey and the public address. It will give you the private key. Then import the private key to whatever thin client you want.
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3 votes

Not able to open BTC Wallet

No, private keys are randomly picked from the space of 256-bit numbers. A private key cannot be recovered from the address, otherwise anyone could take any other user's funds at will. If your friend ...
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  • 64.6k
3 votes
Accepted

If anyone with your seed phrase can generate your wallet private keys, what is the advantage of a hardware wallet?

Well, in both cases, your seed words are ultimately the key to the wallet. If you use a regular wallet, you open yourself up to a number of other attacks Malware on the device that runs the software ...
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  • 16.5k
3 votes
Accepted

How are keys for lightning channels currently created?

While I have experienced the same situation as the person described in the video the information is only partially true. It is very well described in BOLT 03 how keys are being derived. The general ...
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3 votes

Exporting private key from expired bitcoin address (now showing as watch-only)

It is not possible to compute the private key for an address, ever, unless there are severe bugs in the wallet that holds the key. Also addresses don't expire. For privacy reasons it is bad to reuse ...
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3 votes

Is there a database of wallet addresses with lost private keys?

No, because it's not possible to prove a negative ("No I don't have the private key for that address") and I can't think of a use for that.
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  • 9,849
2 votes

How to recover coins from a wallet that uses BIP32 Deterministic Keys?

Here's a web tool for BIP32 key derivation. The only problem is the hardcoded 50k rounds of HMAC-SHA256. You do need to know how your wallet software exactly derived the master private key from the ...
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  • 376
2 votes

Recovering the last few digits of a Litecoin private key

First off: I don't know of any recovery tools (but didn't google for them either). What I'll explain is the difficulty to guess the correct address. The wallet import format has 4 byte of checksum ...
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  • 3,154
2 votes

I can't access my wallet at Bitknock cloud mining anymore

Unfortunately, most of the "cloud mining" websites are ponzi schemes trying to disguise themselves as a cloud mining contract provider. This site catagorizes Bitknock as a ponzi/scam dated back to ...
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  • 1,376
2 votes
Accepted

Recovering Hive Wallet private key with passphrase

Might want to experiment with libbitcoin's command line interface called bitcoin explorer (bx). Instructions for using v3.0 bx commands used below are found here in the right pane. Assuming there is ...
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  • 2,927
2 votes

Trying to recover a blockchain.info wallet from 2013 w/ a 29 (or 13?) word phrase

I ended up adapting gist.github.com/fcicq/3368495 to read from a file with a hundred thousand possible passwords (which I generated by permuting the inputs I was pretty sure I used to generate it in ...
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  • 131
2 votes
Accepted

How does mnemonic recover a single private key?

Typically, they just pick the first one that the mnemonic generates.
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2 votes
Accepted

"Lost" password to BIP38 encrypted private key, encrypter may be faulty (Bippy)

It turns out Bippy does have a bug in the encryption algorithm where it mixes up the public key compression flag. As pointed out, I posted this problem on reddit as well, and a solution has been ...
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