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9f25645be5
Tiny fix correcting the order of commands, for `git checkout` one has to change into the repository directory first.
79 lines
2.4 KiB
Python
79 lines
2.4 KiB
Python
"""Compare ellswift decoding in the BIP-324 test vectors against the SwiftEC reference code.
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Instructions:
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* Clone the SwiftEC repository, and enter the directory:
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git clone https://github.com/Jchavezsaab/SwiftEC
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cd SwiftEC
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git checkout 5320a25035d91addde29d14164cce684b56a12ed
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* Generate parameters for the secp256k1 curve:
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sage --python generate_parameters.py -p secp256k1
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* Copy over this file and the CSV test vectors:
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cp PATH_TO_BIPS_REPO/bips/bip-0324/{*.csv,test_sage_decoding.py} .
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* Run the tests:
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sage --python test_sage_decoding.py -p secp256k1
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No output = good.
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"""
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import sys
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import csv
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from config import F
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from Xencoding_0 import Xdecode
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FILENAME_PACKET_TEST = 'packet_encoding_test_vectors.csv'
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FILENAME_XSWIFTEC_INV_TEST = 'xswiftec_inv_test_vectors.csv'
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FILENAME_ELLSWIFT_DECODE_TEST = 'ellswift_decode_test_vectors.csv'
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def ellswift_decode_sage(ellswift):
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"""Given a 64-byte ellswift encoded public key, get the 32-byte X coordinate."""
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u = F(int.from_bytes(ellswift[:32], 'big'))
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t = F(int.from_bytes(ellswift[32:], 'big'))
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# Reimplement the input correction step.
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if u == F(0):
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u = F(1)
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if t == F(0):
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t = F(1)
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if u**3 + t**2 + 7 == F(0):
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t = F(2) * t
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# Invoke reference code
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x, z = Xdecode(u, t)
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# Convert to bytes.
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return int(x / z).to_bytes(32, 'big')
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with open(FILENAME_PACKET_TEST, newline='', encoding='utf-8') as csvfile:
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reader = csv.DictReader(csvfile)
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for row in reader:
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bytes_ellswift_ours = bytes.fromhex(row['in_ellswift_ours'])
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bytes_ellswift_theirs = bytes.fromhex(row['in_ellswift_theirs'])
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assert row['mid_x_ours'] == ellswift_decode_sage(bytes_ellswift_ours).hex()
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assert row['mid_x_theirs'] == ellswift_decode_sage(bytes_ellswift_theirs).hex()
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with open(FILENAME_XSWIFTEC_INV_TEST, newline='', encoding='utf-8') as csvfile:
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reader = csv.DictReader(csvfile)
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for row in reader:
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udat = bytes.fromhex(row['u'])
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xdat = bytes.fromhex(row['x'])
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for case in range(8):
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tdat = bytes.fromhex(row[f"case{case}_t"])
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if tdat:
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assert ellswift_decode_sage(udat + tdat) == xdat
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with open(FILENAME_ELLSWIFT_DECODE_TEST, newline='', encoding='utf-8') as csvfile:
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reader = csv.DictReader(csvfile)
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for row in reader:
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ellswift = bytes.fromhex(row['ellswift'])
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assert ellswift_decode_sage(ellswift).hex() == row['x']
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