From 70182f71679d0a19b1a63e976ee055b5c26d4db8 Mon Sep 17 00:00:00 2001
From: Mike <mpech@tuta.io>
Date: Thu, 1 Feb 2024 16:12:33 +0200
Subject: [PATCH] .

---
 ed25519.l    |  1 +
 expmod.l     | 13 ++-----------
 scalarmult.l | 39 ++++++++++++++++++++++++++++-----------
 3 files changed, 31 insertions(+), 22 deletions(-)

diff --git a/ed25519.l b/ed25519.l
index e3f94c7..eaf6733 100644
--- a/ed25519.l
+++ b/ed25519.l
@@ -55,6 +55,7 @@
       (% *By *Q) ) )
 
 (de edwards (P Q)
+   (println 'ed 'P P 'Q Q)
    (let
       (X1 (car P)
          Y1 (cdr P)
diff --git a/expmod.l b/expmod.l
index 4f2ce9e..3bc3414 100644
--- a/expmod.l
+++ b/expmod.l
@@ -28,15 +28,6 @@ R 37095705934669439343138083508754565189542113879843219016388785533085940283556
             (bit? 1 I)
             (setq R (modulo (* R B) M)) ) )
       R ) )
-
-(de **Mod (X Y N)
-   (let M 1
-      (loop
-         (when (bit? 1 Y)
-            (setq M (% (* M X) N)) )
-         (T (=0 (setq Y (>> 1 Y)))
-            M )
-         (setq X (% (* X X) N)) ) ) )
 (de expmod-NEW (B E M)
    (if (=0 E)
       1
@@ -49,7 +40,7 @@ R 37095705934669439343138083508754565189542113879843219016388785533085940283556
          R ) ) )
 (println 'expmod-NEW)
 (bench
-   (do 10000
+   (do 100
       (test
          37095705934669439343138083508754565189542113879843219016388785533085940283556
          (expmod-NEW
@@ -58,7 +49,7 @@ R 37095705934669439343138083508754565189542113879843219016388785533085940283556
             57896044618658097711785492504343953926634992332820282019728792003956564819949 ) ) ) )
 (println 'expmod-OLD)
 (bench
-   (do 10000
+   (do 100
       (test
          37095705934669439343138083508754565189542113879843219016388785533085940283556
          (expmod-NEW
diff --git a/scalarmult.l b/scalarmult.l
index 47e0fcb..adf3ba1 100644
--- a/scalarmult.l
+++ b/scalarmult.l
@@ -13,6 +13,8 @@ E 36144925721603087658594284515452164870581325872720374094707712194495455132720
 Q (38815646466658113194383306759739515082307681141926459231621296960732224964046 . 11903303657706407974989296177215005343713679411332034699907763981919547054807)
 }#
 
+(de inv (X)
+   (expmod X (- *Q 2) *Q) )
 (de expmod (B E M)
    (if (=0 E)
       1
@@ -23,10 +25,30 @@ Q (38815646466658113194383306759739515082307681141926459231621296960732224964046
          (when (bit? 1 E)
             (setq R (% (* R B) M)) )
          R ) ) )
-(de inv (X)
-   (expmod X (- *Q 2) *Q) )
+(de xrecover (Y)
+   (let
+      (YY (* Y Y)
+         XX (* (dec YY) (inv (inc (* *D YY))))
+         X (expmod XX (/ (+ *Q 3) 8) *Q) )
+      (and
+         (n0 (% (- (* X X) XX) *Q))
+         (setq X (% (* *I X) *Q)) )
+      (and
+         (n0 (% X 2))
+         (setq X (- *Q X)) )
+      X ) )
+(setq *S (0 -1 -2 -3 -4 -5 -6 -7 .))
+(setq *B 256)
+(setq *Q `(- (** 2 255) 19))
+(setq *L `(+ (** 2 252) 27742317777372353535851937790883648493))
+(setq *D `(* -121665 (inv 121666)))
+(setq *I `(expmod 2 (/ (dec *Q) 4) *Q))
+(setq *By `(* 4 (inv 5)))
+(setq *Bxy
+   (cons
+      (% (xrecover *By) *Q)
+      (% *By *Q) ) )
 (de edwards (P Q)
-   (println 'P P 'Q Q)
    (let
       (X1 (car P)
          Y1 (cdr P)
@@ -36,12 +58,12 @@ Q (38815646466658113194383306759739515082307681141926459231621296960732224964046
          (%
             (*
                (+ (* X1 Y2) (* X2 Y1))
-               (inv (inc (* *D X1 X2 Y1 Y2))) )
+               (inv (inc (* X1 X2 Y1 Y2))) )
             *Q )
          (%
             (*
                (+ (* Y1 Y2) (* X1 X2))
-               (inv (- 1 (* *D X1 X2 Y1 Y2))) )
+               (inv (- 1 (* X1 X2 Y1 Y2))) )
             *Q ) ) ) )
 #{
    def scalarmult(P,e):
@@ -52,24 +74,19 @@ Q (38815646466658113194383306759739515082307681141926459231621296960732224964046
      return Q
 }#
 (de scalarmult (P E)
-   (wait 100)
    (if (=0 E)
       (cons 0 1)
       (let Q (scalarmult P (/ E 2))
-         (println 1)
          (setq Q (edwards Q Q))
-         (println 2)
-
          (when (bit? 1 E)
             (setq Q (edwards Q P)) )
          Q ) ) )
-(trace 'scalarmult)
+# (trace 'scalarmult)
 (println
    (scalarmult
       (15112221349535400772501151409588531511454012693041857206046113283949847762202 . 46316835694926478169428394003475163141307993866256225615783033603165251855960)
       36144925721603087658594284515452164870581325872720374094707712194495455132720 ) )
 
 
-
 (msg 'ok)
 (bye)