From 213796db4bb99b82bc8e1a16e7133b9c9854d51e Mon Sep 17 00:00:00 2001
From: Paul Miller <paul@paulmillr.com>
Date: Sun, 23 Apr 2023 18:28:28 +0000
Subject: [PATCH] ed25519: rename to edwardsToMontgomeryPub

---
 src/ed25519.ts              |  9 +++++----
 test/ed25519-addons.test.js | 13 ++++++-------
 2 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/src/ed25519.ts b/src/ed25519.ts
index a7dce4d..5649401 100644
--- a/src/ed25519.ts
+++ b/src/ed25519.ts
@@ -104,10 +104,10 @@ const ed25519Defaults = {
   // d is equal to -121665/121666 over finite field.
   // Negative number is P - number, and division is invert(number, P)
   d: BigInt('37095705934669439343138083508754565189542113879843219016388785533085940283555'),
-  // Finite field 𝔽p over which we'll do calculations; 2n ** 255n - 19n
+  // Finite field 𝔽p over which we'll do calculations; 2n**255n - 19n
   Fp,
   // Subgroup order: how many points curve has
-  // 2n ** 252n + 27742317777372353535851937790883648493n;
+  // 2n**252n + 27742317777372353535851937790883648493n;
   n: BigInt('7237005577332262213973186563042994240857116359379907606001950938285454250989'),
   // Cofactor
   h: BigInt(8),
@@ -165,13 +165,14 @@ export const x25519 = montgomery({
  * @example
  *   const someonesPub = ed25519.getPublicKey(ed25519.utils.randomPrivateKey());
  *   const aPriv = x25519.utils.randomPrivateKey();
- *   x25519.getSharedSecret(aPriv, edwardsToMontgomery(someonesPub))
+ *   x25519.getSharedSecret(aPriv, edwardsToMontgomeryPub(someonesPub))
  */
-export function edwardsToMontgomery(edwardsPub: Hex): Uint8Array {
+export function edwardsToMontgomeryPub(edwardsPub: Hex): Uint8Array {
   const { y } = ed25519.ExtendedPoint.fromHex(edwardsPub);
   const _1n = BigInt(1);
   return Fp.toBytes(Fp.create((_1n + y) * Fp.inv(_1n - y)));
 }
+export const edwardsToMontgomery = edwardsToMontgomeryPub; // deprecated
 
 /**
  * Converts ed25519 secret key to x25519 secret key.
diff --git a/test/ed25519-addons.test.js b/test/ed25519-addons.test.js
index 3c8e052..2eac266 100644
--- a/test/ed25519-addons.test.js
+++ b/test/ed25519-addons.test.js
@@ -8,7 +8,7 @@ import {
   ed25519,
   ed25519ctx,
   ed25519ph,
-  edwardsToMontgomery,
+  edwardsToMontgomeryPub,
   edwardsToMontgomeryPriv,
   RistrettoPoint,
   x25519,
@@ -172,7 +172,7 @@ describe('RFC7748 X25519 ECDH', () => {
       hex(xPrivate),
       'a8cd44eb8e93319c0570bc11005c0e0189d34ff02f6c17773411ad191293c94f'
     );
-    const xPublic = edwardsToMontgomery(edPublic);
+    const xPublic = edwardsToMontgomeryPub(edPublic);
     deepStrictEqual(
       hex(xPublic),
       'ed7749b4d989f6957f3bfde6c56767e988e21c9f8784d91d610011cd553f9b06'
@@ -182,10 +182,9 @@ describe('RFC7748 X25519 ECDH', () => {
   should('edwardsToMontgomery should produce correct keyPair', () => {
     const edSecret = ed25519.utils.randomPrivateKey();
     const edPublic = ed25519.getPublicKey(edSecret);
-    const hashed = ed25519.CURVE.hash(edSecret.subarray(0, 32));
-    const xSecret = ed25519.CURVE.adjustScalarBytes(hashed.subarray(0, 32));
+    const xSecret = edwardsToMontgomeryPriv(edSecret);
     const expectedXPublic = x25519.getPublicKey(xSecret);
-    const xPublic = edwardsToMontgomery(edPublic);
+    const xPublic = edwardsToMontgomeryPub(edPublic);
     deepStrictEqual(xPublic, expectedXPublic);
   });
 
@@ -195,8 +194,8 @@ describe('RFC7748 X25519 ECDH', () => {
     const edSecret2 = ed25519.utils.randomPrivateKey();
     const edPublic2 = ed25519.getPublicKey(edSecret2);
     deepStrictEqual(
-      x25519.getSharedSecret(edwardsToMontgomeryPriv(edSecret1), edwardsToMontgomery(edPublic2)),
-      x25519.getSharedSecret(edwardsToMontgomeryPriv(edSecret2), edwardsToMontgomery(edPublic1))
+      x25519.getSharedSecret(edwardsToMontgomeryPriv(edSecret1), edwardsToMontgomeryPub(edPublic2)),
+      x25519.getSharedSecret(edwardsToMontgomeryPriv(edSecret2), edwardsToMontgomeryPub(edPublic1))
     );
   });