- Generate Bitcoin Private Key Offline Windows 10
- Generate Bitcoin Private Key Offline Windows 10
- Generate Bitcoin Private Key Offline Free
Paper wallets are simply Bitcoin private keys printed on a piece of paper. It can have the Bitcoin public address also printed on it, but not necessarily. Paper wallets are an effective way of storing Bitcoin private keys offline. They protect the user against potential theft.
In the previous article, we looked at different methods to generate a private key. Whatever method you choose, you’ll end up with 32 bytes of data. Here’s the one that we got at the end of that article:
- Securing your wallet. Like in real life, your wallet must be secured. Bitcoin makes it possible to transfer value anywhere in a very easy way and it allows you to be in control of your money. Such great features also come with great security concerns. At the same time, Bitcoin can provide very high levels of security if used correctly.
- Apr 04, 2018 btckeygenie is a standalone Bitcoin keypair/address generator written in Go. Btckeygenie generates an ECDSA secp256k1 keypair, dumps the public key in compressed and uncompressed Bitcoin address, hexadecimal, and base64 formats, and dumps the private key in Wallet Import Format (WIF), Wallet Import Format Compressed (WIFC), hexadecimal,.
- Aug 18, 2018 This would depend on the type of wallet you have used. Wallets can be in online, offline, paper or hardware formats. There are quite a few methods to generate private keys. Each of them varies in simplicity and security. A blockchain wallet can co.
- A Bitcoin wallet is as simple as a single pairing of a Bitcoin address with its corresponding Bitcoin private key. Such a wallet has been generated for you in your web browser and is displayed above. To safeguard this wallet you must print or otherwise record the Bitcoin address and private key. It is important to make a backup copy of the private key and store it in a safe location.
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Generate Bitcoin Private Key Offline Windows 10
We’ll use this private key throughout the article to derive both a public key and the address for the Bitcoin wallet.
What we want to do is to apply a series of conversions to the private key to get a public key and then a wallet address. Most of these conversions are called hash functions. These hash functions are one-way conversions that can’t be reversed. We won’t go to the mechanics of the functions themselves — there are plenty of great articles that cover that. Instead, we will look at how using these functions in the correct order can lead you to the Bitcoin wallet address that you can use.
Elliptic Curve Cryptography
The first thing we need to do is to apply the ECDSA or Elliptic Curve Digital Signature Algorithm to our private key. An elliptic curve is a curve defined by the equation y² = x³ + ax + b with a chosen a and b. There is a whole family of such curves that are widely known and used. Bitcoin uses the secp256k1 curve. If you want to learn more about Elliptic Curve Cryptography, I’ll refer you to this article.
By applying the ECDSA to the private key, we get a 64-byte integer. This consists of two 32-byte integers that represent the X and Y of the point on the elliptic curve, concatenated together.
For our example, we got: 1e7bcc70c72770dbb72fea022e8a6d07f814d2ebe4de9ae3f7af75bf706902a7b73ff919898c836396a6b0c96812c3213b99372050853bd1678da0ead14487d7.
Generate Bitcoin Private Key Offline Windows 10
In Python, it would look like this:
Note: as you can see from the code, before I used a method from the ecdsa module, I decoded the private key using codecs. This is relevant more to the Python and less to the algorithm itself, but I will explain what are we doing here to remove possible confusion.
In Python, there are at least two classes that can keep the private and public keys: “str” and “bytes”. The first is a string and the second is a byte array. Cryptographic methods in Python work with a “bytes” class, taking it as input and returning it as the result.
Now, there’s a little catch: a string, say, 4f3c does not equal the byte array 4f3c, it equals the byte array with two elements, O<. And that’s what codecs.decode method does: it converts a string into a byte array. That will be the same for all cryptographic manipulations that we’ll do in this article.
Public key
Once we’re done with the ECDSA, all we need to do is to add the bytes 0x04 at the start of our public key. The result is a Bitcoin full public key, which is equal to: 041e7bcc70c72770dbb72fea022e8a6d07f814d2ebe4de9ae3f7af75bf706902a7b73ff919898c836396a6b0c96812c3213b99372050853bd1678da0ead14487d7 for us.
Compressed public key
But we can do better. As you might remember, the public key is some point (X, Y) on the curve. We know the curve, and for each X there are only two Ys that define the point which lies on that curve. So why keep Y? Instead, let’s keep X and the sign of Y. Later, we can derive Y from that if needed.
The specifics are as follows: we take X from the ECDSA public key. Now, we add the 0x02 if the last byte of Y is even, and the byte 0x03 if the last byte is odd.
In our case, the last byte is odd, so we add 0x03 to get the compressed public key: 031e7bcc70c72770dbb72fea022e8a6d07f814d2ebe4de9ae3f7af75bf706902a7. This key contains the same information, but it’s almost twice as short as the uncompressed key. Cool!
Previously, wallet software used long, full versions of public keys, but now most of it has switched to compressed keys.
Encrypting the public key
From now on, we need to make a wallet address. Whatever method of getting the public key you choose, it goes through the same procedure. Obviously, the addresses will differ. In this article, we will go with the compressed version.
Generate Bitcoin Private Key Offline Free
What we need to do here is to apply SHA-256 to the public key, and then apply RIPEMD-160 to the result. The order is important.
SHA-256 and RIPEMD-160 are two hash functions, and again, we won’t go into the details of how they work. What matters is that now we have 160-bit integer, which will be used for further modifications. Let’s call that an encrypted public key. For our example, the encrypted public key is 453233600a96384bb8d73d400984117ac84d7e8b.
Here’s how we encrypt the public key in Python:
Adding the network byte
The Bitcoin has two networks, main and test. The main network is the network that all people use to transfer the coins. The test network was created — you guessed it — to test new features and software.
We want to generate an address to use it on the mainnet, so we need to add 0x00 bytes to the encrypted public key. The result is 00453233600a96384bb8d73d400984117ac84d7e8b. For the testnet, that would be 0x6f bytes.
Checksum
Now we need to calculate the checksum of our mainnet key. The idea of checksum is to make sure that the data (in our case, the key) wasn’t corrupted during transmission. The wallet software should look at the checksum and mark the address as invalid if the checksum mismatches.
To calculate the checksum of the key, we need to apply SHA-256 twice and then take first 4 bytes of the result. For our example, the double SHA-256 is 512f43c48517a75e58a7ec4c554ecd1a8f9603c891b46325006abf39c5c6b995 and therefore the checksum is 512f43c4 (note that 4 bytes is 8 hex digits).
The code to calculate an address checksum is the following:
Getting the address
Finally, to make an address, we just concatenate the mainnet key and the checksum. That makes it 00453233600a96384bb8d73d400984117ac84d7e8b512f43c4 for our example.
That’s it! That’s the wallet address for the private key at the start of the article.
But you may notice that something is off. You’ve probably seen a handful of Bitcoin addresses and they didn’t look like that. Well, the reason is that they are encoded with Base58. It’s a little bit odd.
Here’s the algorithm to convert a hex address to the Base58 address:
What we get is 17JsmEygbbEUEpvt4PFtYaTeSqfb9ki1F1, a compressed Bitcoin wallet address.
Conclusion
The wallet key generation process can be split into four steps:
- creating a public key with ECDSA
- encrypting the key with SHA-256 and RIPEMD-160
- calculating the checksum with double SHA-256
- encoding the key with Base58.
Depending on the form of public key (full or compressed), we get different addresses, but both are perfectly valid.
Here’s the full algorithm for the uncompressed public key:
If you want to play with the code, I published it to the Github repository.
I am making a course on cryptocurrencies here on freeCodeCamp News. The first part is a detailed description of the blockchain.
I also post random thoughts about crypto on Twitter, so you might want to check it out.
Like in real life, your wallet must be secured. Bitcoin makes it possible to transfer value anywhere in a very easy way and it allows you to be in control of your money. Such great features also come with great security concerns. At the same time, Bitcoin can provide very high levels of security if used correctly. Always remember that it is your responsibility to adopt good practices in order to protect your money.
Be careful with online services
You should be wary of any service designed to store your money online. Many exchanges and online wallets suffered from security breaches in the past and such services generally still do not provide enough insurance and security to be used to store money like a bank. Accordingly, you might want to use other types of Bitcoin wallets. Otherwise, you should choose such services very carefully. Additionally, using two-factor authentication is recommended.
Small amounts for everyday uses
A Bitcoin wallet is like a wallet with cash. If you wouldn't keep a thousand dollars in your pocket, you might want to have the same consideration for your Bitcoin wallet. In general, it is a good practice to keep only small amounts of bitcoins on your computer, mobile, or server for everyday uses and to keep the remaining part of your funds in a safer environment.
Backup your wallet
Stored in a safe place, a backup of your wallet can protect you against computer failures and many human mistakes. It can also allow you to recover your wallet after your mobile or computer was stolen if you keep your wallet encrypted. Electronic service analyst key generator.
Backup your entire wallet
Some wallets use many hidden private keys internally. If you only have a backup of the private keys for your visible Bitcoin addresses, you might not be able to recover a great part of your funds with your backup.
Encrypt online backups
Any backup that is stored online is highly vulnerable to theft. Even a computer that is connected to the Internet is vulnerable to malicious software. As such, encrypting any backup that is exposed to the network is a good security practice.
Use many secure locations
Single points of failure are bad for security. If your backup is not dependent of a single location, it is less likely that any bad event will prevent you to recover your wallet. You might also want to consider using different medias like USB keys, papers and CDs.
Make regular backups
You need to backup your wallet on a regular basis to make sure that all recent Bitcoin change addresses and all new Bitcoin addresses you created are included in your backup. However, all applications will be soon using wallets that only need to be backed up once.
Encrypt your wallet
Encrypting your wallet or your smartphone allows you to set a password for anyone trying to withdraw any funds. This helps protect against thieves, though it cannot protect against keylogging hardware or software.
Never forget your password
You should make sure you never forget the password or your funds will be permanently lost. Unlike your bank, there are very limited password recovery options with Bitcoin. In fact, you should be able to remember your password even after many years without using it. In doubt, you might want to keep a paper copy of your password in a safe place like a vault.
Use a strong password
Any password that contains only letters or recognizable words can be considered very weak and easy to break. A strong password must contain letters, numbers, punctuation marks and must be at least 16 characters long. The most secure passwords are those generated by programs designed specifically for that purpose. Strong passwords are usually harder to remember, so you should take care in memorizing it.
Offline wallet for savings
An offline wallet, also known as cold storage, provides the highest level of security for savings. It involves storing a wallet in a secured place that is not connected to the network. When done properly, it can offer a very good protection against computer vulnerabilities. Using an offline wallet in conjunction with backups and encryption is also a good practice. Here is an overview of some approaches.
Offline transaction signing
This approach involves having two computers sharing some parts of the same wallet. The first one must be disconnected from any network. It is the only one that holds the entire wallet and is able to sign transactions. The second computer is connected to the network and only has a watching wallet that can only create unsigned transactions. This way, you can securely issue new transactions with the following steps.
- Create a new transaction on the online computer and save it on an USB key.
- Sign the transaction with the offline computer.
- Send the signed transaction with the online computer.
Because the computer that is connected to the network cannot sign transactions, it cannot be used to withdraw any funds if it is compromised. Armory can be used to do offline transaction signature.
Hardware wallets
Hardware wallets are the best balance between very high security and ease of use. These are little devices that are designed from the root to be a wallet and nothing else. No software can be installed on them, making them very secure against computer vulnerabilities and online thieves. Because they can allow backup, you can recover your funds if you lose the device.
Keep your software up to date
Using the latest version of your Bitcoin software allows you to receive important stability and security fixes. Updates can prevent problems of various severity, include new useful features and help keep your wallet safe. Installing updates for all other software on your computer or mobile is also important to keep your wallet environment safer.
Multi-signature to protect against theft
Bitcoin includes a multi-signature feature that allows a transaction to require multiple independent approvals to be spent. This can be used by an organization to give its members access to its treasury while only allowing a withdrawal if 3 of 5 members sign the transaction. Some web wallets also provide multi-signature wallets, allowing the user to keep control over their money while preventing a thief from stealing funds by compromising a single device or server.
Think about your testament
Your bitcoins can be lost forever if you don't have a backup plan for your peers and family. If the location of your wallets or your passwords are not known by anyone when you are gone, there is no hope that your funds will ever be recovered. Taking a bit of time on these matters can make a huge difference.