I can provide you with an article on how to extract r and s (private and public keys) from a signature using Python.
Understanding the Ethereum Signature Format
Ethereum signatures are based on the Elliptic Curve Digital Signature Algorithm (ECDSA). The signature format consists of a signature hash, r and s components. Here is the format breakdown:
signature_hash
: 64-byte hash of the message
- “r”: 256-bit public key component
s
: 256-bit private key component
Python code
Here is an example Python code snippet showing how to extract the r and s components from a signature:
import hashlib
Crypto.PublicKey import EC
Define the signature hashsignature_hash = b'\x02\x01\x00\x00\x03\x12\x11\x14'
Extract the signature hash (hexadecimal)hex_signature_hash = signature_hash.hex()
Get the public key componentspublic_key = EC().key
r_component = hex(signature_hash).replace('\x00', '')
s_component = hex(public_key.r)
Note: Elliptic curve uses x instead of yprint(f"r_component (bytes): {r_component}")
print(f"s_component (hex): {s_component}")
Explanation
- First, we define the signature hash as a byte object.
- We extract the signature hash in hexadecimal format using the
hex() method.
- We generate an EC key from the public key component (Elliptic curve uses x instead of y). Note that we use the letter x instead of y because ECDSA is based on elliptic curves, which have a different order of curves than RSA.
- We extract the r and s components by converting the hexadecimal signature hash value to bytes using thereplace(‘\x00’, ”)
method, which removes all whitespace characters (
\x00`). The r component is now in bytes, while the s component remains in hexadecimal.
Note: In Ethereum, ECDSA uses a different curve ordering than RSA. We use x instead of y because the elliptic curve uses x instead of y.
Example use case
You can use this code snippet to verify the authenticity and integrity of a signature. For example, you can create a new public key component using the following code:
public_key = EC().key
output(public_key)
This prints the public key component in bytes.
Hope this helps! Let me know if you have any questions or need further assistance.