diff --git a/src/core/utils/x25519.ts b/src/core/utils/x25519.ts
index 2729d80a..7e69f339 100644
--- a/src/core/utils/x25519.ts
+++ b/src/core/utils/x25519.ts
@@ -3,6 +3,8 @@ import { x25519 } from "@noble/curves/ed25519";
 export function getX25519PrivateKey(): Uint8Array {
   const key = x25519.utils.randomPrivateKey();
 
+  // scalar clamping for curve25519, according to
+  // https://www.rfc-editor.org/rfc/rfc7748#section-5
   key[0] &= 248;
   key[31] &= 127;
   key[31] |= 64;