What is a Private Key?
- C Generate Bitcoin Private Key Database
- C Generate Bitcoin Private Keys
- C Generate Bitcoin Private Key With Balance
Oct 31, 2015 Libbtc is a very portable C library for creating and manipulating bitcoin data structures and interacting with the p2p network. Current features. Generating and storing private and public keys; ECDSA secp256k1 signing and verification (through libsecp256k1 included as git subtree) Generate recoverable signatures (and recover pubkey from signatures).
- I found the following code online and apparently it works. But I don't understand the lines which extract the Bitcoin compatible private/public key from the created ECDSA keypair.
- What is a Bitcoin private key? A Bitcoin private key is a secret number which every Bitcoin wallet has. This 256-bit number can be represented in several formats: in hexadecimal – 256 bits, in hexadecimal is 32 bytes, or 64 characters in the range 0-9 or A-F, Base64 string, a WIF key, or a mnemonic phrase.
A private key is a secret 256-bit long number randomly selected when you create a Bitcoin wallet. This is the address which enables you to send the Bitcoins to a recipient’s address. You never share the private key to anyone.
The number and type of cryptographic functions implemented for security reasons defines just how random and unique the key is.
A private uncompressed key always begins with a 5 and it looks like this:
5Hwgr3u458GLafKBgxtssHSPqJnYoGrSzgQsPwLFhLNYskDPyyA
What is a Public Key?
A public key is another address consisting of numbers and letters which is a derivate from private keys after they have been encrypted via the use of mathematical functions. The encryption process cannot be reversed and thus no one can find out the original private key. This is the address that enables you to receive Bitcoins.
The hash of a public key is always 1:
1BvBMSEYstWetqTFn5Au4m4GFg7xJaNVN2
This address you publicly make available in order to receive Bitcoins. There is no limit to how many public addresses a user can generate. In order to generate such a key and subsequently a wallet address, there have to be applied a number of conversions to the private key. These conversions are known as hash functions, which are un-reversible conversions.
Creating a Public Key with ECDSA
The first thing you have to do is apply to your private key an ECDSA, also know as Elliptic Curve Digital Signature Algorithm. An elliptic curve is defined by the equation y² = x³ + ax + b with selected value for a and b. There is an entire family of these curves which can be applied. Bitcoin makes use of the secp256k1 curve.
Applying an ECDSA to the private key will result in a 64-byte integer composed of two 32-byte integers put together which represent the X and Y of the point on the elliptic curve.
Below is the code you would require in Python language:
private_key_bytes = codecs.decode(private_key, ‘hex’)
# Get ECDSA public key
Download game killer cho pc. key = ecdsa.SigningKey.from_string(private_key_bytes, curve=ecdsa.SECP256k1).verifying_key
key_bytes = key.to_string()
key_hex = codecs.encode(key_bytes, ‘hex’)
In the code presented above the private keys were decoded with codecs. As in Python, there are at least two classes that can keep the private and public keys, “str”, a string array, and “bytes”- a byte array, things can get a little confusing.
This is because an X string array is not equal to an X byte array, but it equals the byte array with two elements, O<. The codecs.decode method converts a string into a byte array.
After applying ECDSA, we will have to add the bytes 0x04 (04 as a prefix) to the resulted public key. This will generate a Bitcoin full public key.
Compressing the public key
Instead of using the long version of the public key we can compress it to be shorter.
This is done by taking the X from the ECDSA public key and adding 0x02 if the last byte of Y is even, and the 0x03 byte if the last byte is odd.
Encrypting the Key with SHA-256 And RIPEMD-160
Now we move on to create our wallet address. Regardless of the method applied to the public key, the procedure is the same. Obviously, you will have different resulting addresses.
For this, we will need to apply two hash functions: first, we apply SHA-256 to the public key, and then encrypt the result using RIPEMD-160. It is very important that the algorithms are applied in this exact order.
At the end of this process, you will have a 160-bit integer which represents an encrypted public key.
Below is the code needed to encrypt the public key in Python:
public_key_bytes = codecs.decode(public_key, ‘hex’)
# Run SHA-256 for the public key
sha256_bpk = hashlib.sha256(public_key_bytes)
sha256_bpk_digest = sha256_bpk.digest() Talking tom software free download for android mobile.
# Run RIPEMD-160 for the SHA-256
ripemd160_bpk = hashlib.new(‘ripemd160’)
ripemd160_bpk.update(sha256_bpk_digest)
ripemd160_bpk_digest = ripemd160_bpk.digest()
ripemd160_bpk_hex = codecs.encode(ripemd160_bpk_digest, ‘hex’)
Adding the network byte
As Bitcoin has two networks, main and test, we will need to create an address which will be used on the mainnet. This means that we will have to add 0x00 bytes to the encrypted public key. For testnet use, you would have to add 0x6f bytes. Generate ssh key ubuntu gitlab.
Calculating the Checksum
Error 1068 windows 7. The next step is to calculate the checksum of the resulted mainnet key. A checksum ensures that the key has still maintained its integrity during the process. If the checksum does not match, the address will be marked as invalid.
In order to generate a key’s checksum, the SHA-256 hash function must be applied twice and then take the first 4 bytes from this result. Keep in mind that 4 bytes represent 8 hex digits.
The code required for calculating an address checksum is:
# Double SHA256 to get checksum
sha256_nbpk = hashlib.sha256(network_bitcoin_public_key_bytes)
sha256_nbpk_digest = sha256_nbpk.digest()
sha256_2_nbpk = hashlib.sha256(sha256_nbpk_digest)
sha256_2_nbpk_digest = sha256_2_nbpk.digest() Ddj sx2 traktor pro 3.
sha256_2_hex = codecs.encode(sha256_2_nbpk_digest, ‘hex’)
checksum = sha256_2_hex[:8]
Now the last step required to make an address is to merge the mainnet key and the checksum.
Encoding the Key with Base58
You will notice that the resulted key does not look like other BTC addresses. This is because most convert them to a Base58 address.
Below is the algorithm needed to convert a hex address to a Base58 address:
def base58(address_hex):
alphabet = ‘123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz’
b58_string = ‘’
# Get the number of leading zeros
leading_zeros = len(address_hex) — len(address_hex.lstrip(‘0’))
# Convert hex to decimal
address_int = int(address_hex, 16)
# Append digits to the start of string
while address_int > 0:
digit = address_int % 58
digit_char = alphabet[digit]
b58_string = digit_char + b58_string
address_int //= 58
# Add ‘1’ for each 2 leading zeros
ones = leading_zeros // 2
for one in range(ones):
b58_string = ‘1’ + b58_string
return b58_string
The resulted string will represent a compressed Bitcoin wallet address.
Conclusion
The process of generating a Bitcoin wallet address from a private key is not that difficult if you pay close attention to the aforementioned steps.
If your private key is full or compressed, the resulting addresses will look different, but both of them are just as valid.
What is a Bitcoin private key?
A Bitcoin private key is a secret number which every Bitcoin wallet has. This 256-bit number can be represented in several formats: in hexadecimal – 256 bits, in hexadecimal is 32 bytes, or 64 characters in the range 0-9 or A-F, Base64 string, a WIF key, or a mnemonic phrase.
Here is an example:
E9873D79C6D87DC0FB6A5778633389F4453213303DA61F20BD67FC233AA33262
First method
The simplest way of generating a 32-byte integer is to use an RNG library in the language you know. Here are a few examples in Python:
bits = random.getrandbits(256)
# 30848827712021293731208415302456569301499384654877289245795786476741155372082
bits_hex = hex(bits)
# 0x4433d156e8c53bf5b50af07aa95a29436f29a94e0ccc5d58df8e57bdc8583c32
private_key = bits_hex[2:]
# 4433d156e8c53bf5b50af07aa95a29436f29a94e0ccc5d58df8e57bdc8583c32
However, normal RNG libraries are not the most secure options of generating a key. As the generated string is based on a seed, the seed represents the current time. And if you know the time, several brute-force attacks can be applied to it.
Cryptographically strong RNG
In addition to a standard RNG method, Programming languages provide a RNG for specific cryptographic tasks. As the entropy is generated directly from the operating system, this method ensures more security.
It makes this RNG more difficult to reproduce as you can’t determine the time of generation or the seed because it lacks one. No seed is required as it’s created by the program itself.
In Python, you can implement the cryptographically strong RNG in the secret module.
bits = secrets.randbits(256)
# 46518555179467323509970270980993648640987722172281263586388328188640792550961
bits_hex = hex(bits)
# 0x66d891b5ed7f51e5044be6a7ebe4e2eae32b960f5aa0883f7cc0ce4fd6921e31
private_key = bits_hex[2:]
# 66d891b5ed7f51e5044be6a7ebe4e2eae32b960f5aa0883f7cc0ce4fd6921e31
Specialized sites
There are several sites which can generate these numbers randomly for you. Random.org is a site which randomly generates numbers for various purposes. Another popular site is bitaddress.org specifically designed to generate Bitcoin private keys.
As you have no way of knowing if random.org keeps or records any of the generated numbers, it is not such a secure option.
Bitaddress.org, however, is an open source, which means you can check its code to see what it does, and you can also download and run it on your computer in offline mode.
The program uses your mouse or key movements to generate entropy. This makes it highly improbable to reproduce your results.
Then, the private key is delivered in a compressed WIF format, but we will make the algorithm return a hex string which will be required later on for a public key generation.
Bitaddress first initializes a byte array, trying to get as much entropy as possible from your computer. It fills the array with the user input, and then it generates a private key. The service uses the 256-byte array to store entropy. This array is filled in cycles, so when the array is filled for the first time, the pointer resets to zero, the array is filled out again.
After an array is initiated from Window.crypto, it writes a timestamp to generate 4 additional bytes of entropy. It collects data such as the size of the screen, your time zone, information about browser plugins, your locale, among others to add another 6 bytes.
Then after initialization, the program repeatedly waits for the user input to rewrite initial bytes. When the cursor is moved, the position of the cursor is written. When buttons are pressed, the char code of the pressed button is written by the program.
The accumulated entropy to generate a private key of 32 bytes by using an RNG algorithm is called ARC4.
The DIY Version
You can also create your own version of Bitaddress. We will not be gathering data regarding the user’s computer and location. The entropy will be generated only by text, as it’s rather difficult to initialize a position of the cursor via a Python script.
The byte array will be initialized with a cryptographic RNG, then the timestamp will be filled, followed by the filling with a user-generated string.
After filling the second seed pool, the library will allow you to create the key.
Initializing the pool
We insert several bytes from cryptographic RNG and a timestamp. __seed_int and __seed_byte are two methods that will help insert the entropy into the pool array. We will also use the secrets module in our example.
def __init_pool(self):
for i in range(self.POOL_SIZE):
random_byte = secrets.randbits(8)
C Generate Bitcoin Private Key Database
self.__seed_byte(random_byte)
time_int = int(time.time())
self.__seed_int(time_int)
def __seed_int(self, n):
self.__seed_byte(n)
self.__seed_byte(n >> 8)
self.__seed_byte(n >> 16)
self.__seed_byte(n >> 24)
Futura font download for mac. def __seed_byte(self, n):
self.pool[self.pool_pointer] ^= n & 255
self.pool_pointer += 1
if self.pool_pointer >= self.POOL_SIZE:
self.pool_pointer = 0
Here, we insert a timestamp and then we input each character of the string.
def seed_input(self, str_input):
time_int = int(time.time())
self.__seed_int(time_int) Kaspersky 2013 internet security key generator.
for char in str_input:
char_code = ord(char)
self.__seed_byte(char_code)
Generating the private key
In order to generate a 32-byte number with our pool, we have to use a shared object that is employed by any code that is running in one script.
To save our entropy each time a key is generated, the state we stopped at will be remembered and set for the next time a key will be generated.
Now we just need to ensure that our key is in range (1, CURVE_ORDER), which is required for ECDSA private keys. The CURVE_ORDER is the secp256k1 curve’s order.
We will be converting the key to hex, and remove the ‘0x’ part.
def generate_key(self):
big_int = self.__generate_big_int()
big_int = big_int % (self.CURVE_ORDER — 1) # key < curve order
big_int = big_int + 1 # key > 0
C Generate Bitcoin Private Keys
key = hex(big_int)[2:]
return key
def __generate_big_int(self):
if self.prng_state is None:
seed = int.from_bytes(self.pool, byteorder=’big’, signed=False)
random.seed(seed)
self.prng_state = random.getstate()
random.setstate(self.prng_state)
big_int = random.getrandbits(self.KEY_BYTES * 8)
self.prng_state = random.getstate()
return big_int
In order to use the library, you can generate a private key using the following code:
kg = KeyGenerator()
kg.seed_input
kg.generate_key()
# 60cf347dbc59d31c1358c8e5cf5e45b822ab85b79cb32a9f3d98184779a9efc2
You will notice that each time you run the code you will get different results.
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Conclusion
Varying in terms of the level of security and ease of implementation, there are many methods that can help you generate your private keys.