Detecting Duplicate Root Private Keys in Bitcoin
In the vast and complex world of blockchain cryptography, detecting duplicate root private keys is essential to ensuring the integrity and security of a decentralized network. Extended public keys are an essential component of Bitcoin’s cryptographic infrastructure, allowing users to create multiple unique digital identities. However, the same root private key can be used to derive multiple extended public keys, compromising the security of the system.
In this article, we will explore how to detect if two extended public keys have the same root private key using a simple example and provide information on the potential risks involved.
Derivation Process
To derive an extended public key, three different pieces of information need to be combined:
- Parent Key: A long string that serves as the parent key for derivation.
- Chaincode: A unique identifier that ensures that each user’s account is linked to a specific wallet.
- Version and salt: Optional parameters that add additional security features.
The following Python script illustrates how to derive an extended public key using Bitcoin’s cryptography
library:
from cryptography.hazmat.primitives import hash, serialization
from cryptography.hazmat.primitives.asymetric import padding
import axis
def generate_key(parent_key, chaincode, version=None, salt=None):
if version, not instance(version, int) or version < 0:
raise ValueError("Invalid version")
Create a new EC key pair using the parent key and public key parameters.ec = hash.ECDSA(hash.SHA256(), serialization.ders)
e_key = ec.generate_key()
Combine the parent key, chaincode, and optionally the version and salt to create an extended key.key = (
byte.fromhex(parent_key[:40]),
byte.fromhex(parent_key[40:],
encoding=errors.UTF8),
salt if nothing else rises,
e_key.public_bytes(
encoding=serialization.Encoding.PEM,
format=serialization.PublicFormat.SubjectPublicKeyInfo
)
)
backspace
Generate three extended public keys.parent_key1 = "035f743ee7d73d27e8c80f6b2458e6d4e2a45f3d7dd35c4e4d84ff3d939d09f40c"
chaincode1 = "1234567890abcdef"
key1 = generate_key(parent_key1, chaincode1)
parent_key2 = "035f743ee7d73d27e8c80f6b2458e6d4e2a45f3d7dd35c4e4d84ff3d939d09f40c"
chaincode2 = "1234567890abcdef"
key2 = generate_key(parent_key2, chaincode2)
parent_key3 = "035f743ee7d73d27e8c80f6b2458e6d4e2a45f3d7dd35c4e4d84ff3d939d09f40c"
chaincode3 = "1234567890abcdef"
key3 = generate_key(parent_key3, chaincode3)
Compare extended keys.if key1 == key2 and key1 != key3:
print("The two extended public keys have the same root private key.")
else:
print("No duplicate root private keys found.")
Detecting Duplicate Root Private Keys
To find out if two extended public keys have the same root private key, you can compare them using the ==
operator. If both keys are identical, they share a common root private key.
In this example, we generate three different extended public keys using the same parent key and chaincode. We then compare these keys to detect duplicate root private keys:
if key1 == key2 and key1 != key3:
print("The two extended public keys have the same root private key.")
other:
print("No duplicate root private keys found.")
Conclusion
Detecting duplicate root private keys is essential to maintaining the security of the Bitcoin blockchain network. By comparing extended public keys generated from different parent keys and chaincodes, you can identify duplicates and take corrective measures to prevent account compromise.
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