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:
- Generate Bitcoin Wallet From Private Key Password
- Generate Bitcoin Wallet From Private Key Finder
- Online Private Key Bitcoins
- Import Bitcoin Private Key
- Private Key Bitcoin Wallet
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- Sep 22, 2017 Enter or scan any private key to verify that the key is valid and show its corresponding public key. If your private key validates, then you may be reassured that you will able to retrieve any funds sent to that wallet. To duplicate or BIP38-encrypt any paper wallet, just validate its private key and click the 'Use these details to print a.
- Wallet Getting Bx To Create A Private Key From Known Chain Code How To Create Bitcoin Private Key Ethereum Project On Visual Studio Exporting Private Key From Bitcoin Clients Generate A Bitcoin Private Key Forex Trading Bitcoin Wallet Pub! Lic Key Ethereum Connect Coin How To Generate Your Very Own Bitcoin Private Key.
- 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.
We’ll use this private key throughout the article to derive both a public key and the address for the Bitcoin wallet.
An example private key. In Bitcoin, a private key is a 256-bit number, which can be represented one of several ways. Here is a private key in hexadecimal - 256 bits in hexadecimal is 32 bytes, or 64 characters in the range 0-9 or A-F. I would like to generate a totally new bitcoin address on the offline computer, and use it as a cold storage address. I will then sign an offline transaction from the wallet to that new address and be safe. How can I create a new Bitcoin private key from the Bitcoin CLI, without using any existing wallet keys / addresses?
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.
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.
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:
Generate Bitcoin Wallet From Private Key Password
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.
Before getting started with importing your wallet's private keys, let's clarify three important definitions.
- Backup: A file containing a wallet's private key information. Backups can be exported from a wallet or imported to a wallet.
- **Export: **The process of creating a file containing a wallet's private key data. Exported keys can be imported to a new/different wallet to give access to the Bitcoins associated with the exported private key(s).
- **Import: **The process of gaining control of Bitcoin via an exported backup. Wallets can import private keys via text files or QR code scanning.
Bitcoin is not stored locally on your phone or laptop. They are stored on the blockchain and you use a Bitcoin wallet to access the coins for sending/receiving the cryptocurrency. This means if you lose your phone or buy a new laptop you can access your Bitcoin by importing your key(s) from a previously exported backup. With a backup, you are able to recover your Bitcoin at any time by importing the private keys associated with that wallet from the backup. This is why it is imperative that users take the time to create a backup of their wallet before adding Bitcoin to it. For more on creating a backup, please see our Bitcoin.com wallet guide. If you have not already done so, please go ahead and backup your wallet. This process is covered in detail in the guide on how to use the Bitcoin.com wallet. If you do not backup your wallet and store this information somewhere safe you run the risk of losing all bitcoins on that address in the event that you lose or damage the device on which your wallet is installed. Once you have a backup, you are ready to proceed.
Exporting your Bitcoin.com Wallet
To export your Bitcoin.com wallet private keys by file/text, please follow the steps below:
- Open your Bitcoin.com app and select the wallet you wish to export.
- Next tap on the settings cog in the top right of your screen.
- Select 'More Options'.
- Now select 'Export Wallet' from the list.
- Select File/Text (the QR code option will be discussed below).
- It’s important at this point to choose a strong password. A good passphrase is one that is very difficult for others to guess, but easy for you to remember. Do not select well-known quotes or sayings.
The Bitcoin.com Wallet will not allow you to proceed without a password. This is because exporting your wallet involves exposing your private keys to the system clipboard, or worse, sending your private keys unencrypted by email. Once you have a password set up, it’s safe to press “Copy to clipboard” or “Send by email”. You can also chose to export your wallet without the private keys. To do this just tap on 'Show Advanced Options' and check the 'Do not include private key' option. Please note that you will not be able to spend from the wallet without the private key.
Exporting via QR Code
The QR code method of exporting your wallet is best suited for quickly exporting a wallet and then immediately importing it onto another device via QR code scan. If you’re switching devices and want to move your Bitcoin wallet to your new device with the Bitcoin.com wallet installed, you would select “QR Code” as your export method. If you have more than 1 sub-wallet in your Bitcoin.com app, you will have to export each of them individually. Driver detective registration key generator free.
- To export your wallet by QR code, please follow steps 1 to 4 from above and then select 'QR Code'.
- This will display your private key QR code (be careful, anyone who scans this will have access to your wallet).
- Now just scan the QR code with your new phone and you will have the same wallet on your new device.
Importing private key text to your Bitcoin.com wallet
Generate Bitcoin Wallet From Private Key Finder
This is how to import using the copy-to-clipboard method. If you receive an email on your device with your exported wallet, or choose 'Copy to clipboard', on most devices you can press the screen and wait for a “Paste” button to appear, then paste the backup code in to the field.
- From the Home screen, tap 'Create new wallet' or (if you already have a wallet and want to import a new one) tap the '+' symbol.
- Select Import wallet.
- Choose the File/Text tab at the top.
- Paste the backup into the text field, then enter the password for this wallet.
- Press Import Wallet.
If you pasted the backup code correctly and entered the correct password your bitcoin wallet will be imported. A popup window will be shown if your password was incorrect, or the code was improperly pasted. Note, everything within the curly braces { and } including the curly braces should be pasted in order to correctly import the wallet.
Importing a private key using a QR code
The QR code method of exporting your wallet is best suited for quickly exporting a wallet and then immediately importing it onto another device via QR code scan. If you’re switching devices and want to move your Bitcoin wallet to your new device with the Bitcoin.com wallet installed, you would select 'QR Code' as your export method.
Online Private Key Bitcoins
- Source device: the one where wallet currently resides and from which you want to export.
- Destination device: the new device to which you want to import your wallet.
- On the source device, navigate to Settings>Choose Wallet-to-Export>More Options>Export Wallet>QR Code Tab. This will display your QR code (be careful, anyone who scans this will have access to your wallet).
- On the destination device, simply tap the Scan tab to open your camera. Align the QR code within the frame until it syncs.
- Select 'Import' to complete the process.
Once you verify this worked and your wallet shows up on the destination device, you can delete the old wallet and destroy the old device or wipe it for resale. Remember to take basic security precautions. Always do this in a private, secure room or space. The QR code, if seen, can be photographed or scanned by others in public.
Importing a private key using the 12-word recovery phrase
This method of importing a private key involves using your hand-written 12-word 'seed' phrase that you can obtain from the backup process within the Bitcoin.com wallet. For a refresher on how to obtain your backup seed phrase, see our Bitcoin.com wallet guide. To import your wallet using the seed phrase:
Import Bitcoin Private Key
- From the Home screen, Create new wallet or (if you already have a wallet and want to import a new one) tap the '+' symbol.
- Select Import wallet.
- Type in the Recovery Phrase (usually a string of 12 words) into the appropriate text field at the top of the page.
- Press Import.
Private Key Bitcoin Wallet
This completes the guide to importing your private key(s) into your Bitcoin.com wallet. If you have any further questions. Visit the Bitcoin.com Forum.
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