From e938627bcf89f3083a0017eba61f4e0143625ba1 Mon Sep 17 00:00:00 2001
From: root <roadicing>
Date: Wed, 20 Dec 2023 07:02:52 +0000
Subject: [PATCH] Validate p in ModularSquareRoot

---
 nbtheory.cpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/nbtheory.cpp b/nbtheory.cpp
index 7e60be4b6..b17548960 100644
--- a/nbtheory.cpp
+++ b/nbtheory.cpp
@@ -543,6 +543,9 @@ Integer CRT(const Integer &xp, const Integer &p, const Integer &xq, const Intege
 
 Integer ModularSquareRoot(const Integer &a, const Integer &p)
 {
+	if (!IsPrime(p))
+		throw InvalidArgument("ModularSquareRoot: p must be a prime");
+
 	if (p%4 == 3)
 		return a_exp_b_mod_c(a, (p+1)/4, p);