ed25519: Fix isEqual to handle points with Z=0.

armfazh · armfazh · commit 48c3b6a2746a · 2025-04-08T14:43:54.000-07:00
diff --git a/sign/ed25519/point.go b/sign/ed25519/point.go
@@ -164,7 +164,7 @@ func (P *pointR1) isEqual(Q *pointR1) bool {
 	fp.Mul(r, r, &P.z)
 	fp.Sub(l, l, r)
 	b = b && fp.IsZero(l)
-	return b
+	return b && !fp.IsZero(&P.z) && !fp.IsZero(&Q.z)
 }
 
 func (P *pointR3) neg() {

Original file line number	Diff line number	Diff line change
`@@ -164,7 +164,7 @@ func (P pointR1) isEqual(Q pointR1) bool {`
`164`	`164`	`fp.Mul(r, r, &P.z)`
`165`	`165`	`fp.Sub(l, l, r)`
`166`	`166`	`b = b && fp.IsZero(l)`
`167`		`- return b`
	`167`	`+ return b && !fp.IsZero(&P.z) && !fp.IsZero(&Q.z)`
`168`	`168`	`}`
`169`	`169`
`170`	`170`	`func (P *pointR3) neg() {`