diff --git a/ed_on_bls12_381/src/curves/mod.rs b/ed_on_bls12_381/src/curves/mod.rs
index 4194bee..7fd3657 100644
--- a/ed_on_bls12_381/src/curves/mod.rs
+++ b/ed_on_bls12_381/src/curves/mod.rs
@@ -24,7 +24,7 @@ pub type SWProjective = short_weierstrass::Projective<JubjubParameters>;
 /// q = 52435875175126190479447740508185965837690552500527637822603658699938581184513.
 ///
 /// a = -1.
-/// d = (10240/10241) mod q
+/// d = -(10240/10241) mod q
 ///   = 19257038036680949359750312669786877991949435402254120286184196891950884077233.
 ///
 /// Sage script to calculate these: