24 votes
Accepted

How can I manually (on paper) calculate a Bitcoin public key from a private key?

I've spent a fair bit of time thinking about this and can provide a fairly comprehensive answer about the state of the art. But unfortunately the TL;DR is that we don't know how to do this (yet) in ...
Andrew Poelstra's user avatar
17 votes

Should I share my seed phrase to earn airdrop tokens?

No, it is not safe. Never share your 12 word phrase. It is a backup of your private key and allows people to spend your money. They only need your public key or Bitcoin address to give you money, not ...
noone392's user avatar
  • 422
13 votes
Accepted

Can a closed source wallet ever be completely trust-less?

The term trustless is often misunderstood. I suspect you mean not needing to trust anyone, but if a program being open source helps for that, aren't you implicitly relying on the people who are ...
Pieter Wuille's user avatar
10 votes

Alert Key Compromised, upgrade required

The network wide Alert system is being retired. No Bitcoins are at risk and this warning may be safely ignored. Upgrade to the newest version of your wallet software to no longer see the alert. Read ...
grajsek's user avatar
  • 266
10 votes
Accepted

BIP32 recommends a 256 bit seed. Why do most Bitcoin wallets only use a 128 bit seed?

The reasons for the 3 numbers: Bitcoin uses 256-bit ECDSA signatures. These require in the order of 2128 steps to find a private key from the public key is known. This is Bitcoin's security level: we ...
Pieter Wuille's user avatar
6 votes

Is holding funds in a Bitcoin paper wallet safe?

Yes. A paper wallet is basically nothing more than your private key on a piece of paper. For usability it is often represented as a QR code though. You can make copies of it, and store several of ...
Erik Goff's user avatar
6 votes
Accepted

Is It Possible to Prove Ownership of Public Key Hash without Public Key?

The simple answer is no. A hashing algorithm is ment to be a one-way function. If it is possible to recreate the public key from the hash, this means that the hashing algorithm is broken. However ...
user44404's user avatar
  • 546
6 votes

Sugar Daddy Bitcoin

It is a scam. He wants to get you comfortable with a process he can exploit later by sending you larger sums and getting you to pay an accomplice most. Maybe in a week or a month he will say he wants ...
RedGrittyBrick's user avatar
5 votes
Accepted

I'm new to Bitcoin, how do I keep my bitcoins secure?

Use a desktop or mobile wallet (Electrum or Mycelium) to spend bitcoins (be sure to write down your recovery seed and store it like a paper wallet). To receive and store them, use offline paper ...
k-l's user avatar
  • 291
5 votes

I'm new to Bitcoin, how do I keep my bitcoins secure?

Wallet The wallet holds the most valuable component of the bitcoin network, your private key. When you go to Bitcoin.org, there are several choices. A HD wallet (Hierarchical Deterministic) is more ...
5 votes

Can a clever hacker still steal everyone's money from the blockchain.info wallet?

They anticipated this type of attack and they are monitoring their JavaScript files, check this website of theirs http://blockchain-status.com/javascript_verifier Also, CloudFlare (the reverse proxy ...
Onur Yapar's user avatar
5 votes

What did I do wrong that caused me to lose bitcoin?

1) If you generate your paper wallet on your computer, you have to fully trust your computer 2) If you use a website for generating your paper wallet, a) you need to trust that website (hopefully its ...
Jonas Schnelli's user avatar
5 votes

Relationship of Bitcoin address and Public Key

Addresses are textually encoded public key hashes, which means that somebody in possession of only the address cannot read the public key - but eventually the public key must be revealed in order to ...
Mark H's user avatar
  • 3,334
5 votes

What stops a wallet from stealing bitcoins?

As @Prayank mentioned before: Nothing. As Ken Thompson said: "you can't trust code that you did not totally create yourself". If you are paranoid, it's better that you use cold wallets and ...
Hypatia's user avatar
  • 151
5 votes

How do wallets work?

Does it create a public key based of private? Yes, a cryptographic routine exists that computes the public key from the private key. maybe on the wallet.dat file? All modern wallet software ...
Pieter Wuille's user avatar
5 votes
Accepted

Someon offered me btc mine trough his mining device

Yes, it's a scam. Don't send them anything.
ieatpizza's user avatar
  • 2,068
4 votes

What is the most secure operating system that I can use to store bitcoins without having to fear a hacker stealing them?

The most secure operating system is no operating system. As Pieter mentioned in the comments, dedicated hardware wallets prevent private keys from leaking out of the secure hardware enclave, and ...
maservant's user avatar
  • 1,021
4 votes
Accepted

Can a clever hacker still steal everyone's money from the blockchain.info wallet?

Yes, the attack you describe is possible. But this isn't specific to blockchain.info nor to online wallets. If an attacker manages to run code on your machine, you're pwned. As long as an attacker ...
shx2's user avatar
  • 803
4 votes

Can a closed source wallet ever be completely trust-less?

No because bitcoin wallets always have access to private keys and have the ability to communicate across the Internet. With this combination of capabilities, closed source wallets could become ...
Mark S.'s user avatar
  • 2,730
4 votes
Accepted

Hardware wallet teardowns and side channel attacks

The researcher Jochen Hoenicke has done some work on the Trezor. He was able to extract the private key by monitoring the power cable with an oscilloscope. Trezor has since updated the firmware to ...
Murch's user avatar
  • 75.3k
4 votes
Accepted

Should I put my bitcoin wallet on an encrypted disk or not?

This only helps when someone malicious has physical access to you hard drive while your computer is not operational (shut down, account logged out, screen locked, etc.). When your operating system is ...
UTF-8's user avatar
  • 3,224
4 votes
Accepted

My blockchain.info wallet was hacked. How can I create a double send to foil the attacker?

So some background as to what happened here. I wanted to claim my bitcoin diamond air drop. I googled and this video came up first. The video played this weird music which I think was hypnotic in ...
Marcus Scipio's user avatar
4 votes
Accepted

How does crypto exchange secure private keys?

Exchanges typically have a split storage setup. They have a hot wallet and a cold wallet. The hot wallet holds private keys on an online server that can quickly send and receive Bitcoin for when ...
Ava Chow's user avatar
  • 70.4k
4 votes
Accepted

How can I safely store and trade Bitcoin and other crypto currencies?

There are several ways to store cryptocurrencies, so let's break them down by use-case and safety-level. Exchanges There are, broadly speaking, two types of exchanges. Centralized exchanges, such as ...
Raghav Sood's user avatar
4 votes
Accepted

Best OS for cold storage

Use TAILS Linux. From the website: Tails is a live operating system that you can start on almost any computer from a USB stick or a DVD. It aims at preserving your privacy and anonymity, and ...
MCCCS's user avatar
  • 10.2k
4 votes
Accepted

What can you do with the private key?

Anyone who knows the private key will have full access and control of any coins stored at the corresponding address. When you put a password on a wallet or login account, that password is only for ...
chytrik's user avatar
  • 18.3k
4 votes

What can you do with the private key?

What if a person has your private key? Then they have independent control over all the unspent Bitcoins associated with that private key. Once they have the private key there is nothing you can do ...
RedGrittyBrick's user avatar
4 votes

Who store seed phrases data

who store the private key adresses of these seed phrases, The private-keys are generated from the seed-phrase by a mathematical function. There is no need to store a list of seed-phrases and ...
RedGrittyBrick's user avatar
4 votes

Blockstream Green Wallet Security

Part of the design is that compromise of their service is a little bit pointless. They can not sign transactions spending your money to begin with, as the transactions also need a signature from your ...
Claris's user avatar
  • 15.4k

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