From 04f4e37a282d221bce12eb5e15426476a2e3da4b Mon Sep 17 00:00:00 2001
From: "adrian.spycher" <adrian.spycher@etu.hesge.ch>
Date: Mon, 9 Jan 2023 20:38:30 +0100
Subject: [PATCH] optimize fermat_factorization
---
algo.py | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/algo.py b/algo.py
index 4098387..ae2f722 100644
--- a/algo.py
+++ b/algo.py
@@ -78,7 +78,7 @@ def exponentiation_rapide(a, exp, n):
return int(r)
-def is_square(a):
+def is_perfect_square(a):
"""Check if a number is a perfect square, based on the "Babylonian algorithm" (Héron's method) for square root,
from : https://stackoverflow.com/questions/2489435/check-if-a-number-is-a-perfect-square
@@ -121,7 +121,7 @@ def fermat_factorization(n):
a = math.ceil(math.sqrt(n)) # a = 26262277040 (for the key given)
b2 = a**2 - n
- while (not is_square(b2)):
+ while ((a + int(math.sqrt(b2))) * (a - int(math.sqrt(b2))) != n): # (not is_perfect_square(b2)):
a += 1
b2 = a**2 - n
--
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