From 971fa7dd4aa1ee6ecf251895f717cfee5534f9c6 Mon Sep 17 00:00:00 2001
From: hh <hh@scrypt.io>
Date: Tue, 30 Jan 2024 10:50:55 +0800
Subject: [PATCH] Fix slice

---
 src/arrayUtils.ts   | 6 +++---
 src/ec/secp256k1.ts | 7 ++++---
 src/ec/secp256r1.ts | 7 ++++---
 src/schnorr.ts      | 5 +++--
 4 files changed, 14 insertions(+), 11 deletions(-)

diff --git a/src/arrayUtils.ts b/src/arrayUtils.ts
index eb9eeef..a01acc3 100644
--- a/src/arrayUtils.ts
+++ b/src/arrayUtils.ts
@@ -1,16 +1,16 @@
-import { method, SmartContractLib, ByteString } from 'scrypt-ts'
+import { method, SmartContractLib, ByteString, slice } from 'scrypt-ts'
 
 // A library that emulates an array interface on top of a ByteString.
 export class ArrayUtils extends SmartContractLib {
     // Get the byte at the given index.
     @method()
     static getElemAt(b: ByteString, idx: bigint): ByteString {
-        return b.slice(Number(idx) * 2, Number(idx) * 2 + 2)
+        return slice(b, idx, idx + 1n)
     }
 
     // Set the byte at the given index.
     @method()
     static setElemAt(b: ByteString, idx: bigint, val: ByteString): ByteString {
-        return b.slice(0, Number(idx) * 2) + val + b.slice(Number(idx) * 2 + 2)
+        return slice(b, 0n, idx) + val + slice(b, idx + 1n)
     }
 }
diff --git a/src/ec/secp256k1.ts b/src/ec/secp256k1.ts
index 21685fc..e32a239 100644
--- a/src/ec/secp256k1.ts
+++ b/src/ec/secp256k1.ts
@@ -11,6 +11,7 @@ import {
     Utils,
     reverseByteString,
     ByteString,
+    slice,
 } from 'scrypt-ts'
 
 import { Point, Signature } from './misc'
@@ -1244,15 +1245,15 @@ export class SECP256K1 extends SmartContractLib {
     @method()
     static pubKey2Point(pubKey: PubKey): Point {
         assert(
-            pubKey.slice(0, 2) == toByteString('04'),
+            slice(pubKey, 0n, 1n) == toByteString('04'),
             'Pub key isn\'t prefixed with "04". This likely means, that it\'s not in compressed form.'
         )
         // Convert signed little endian to unsigned big endian.
         const x = Utils.fromLEUnsigned(
-            reverseByteString(pubKey.slice(2, 66), 32n)
+            reverseByteString(slice(pubKey, 1n, 33n), 32n)
         )
         const y = Utils.fromLEUnsigned(
-            reverseByteString(pubKey.slice(66, 130), 32n)
+            reverseByteString(slice(pubKey, 33n, 65n), 32n)
         )
         return {
             x: x,
diff --git a/src/ec/secp256r1.ts b/src/ec/secp256r1.ts
index 9c7c63c..d80e8d3 100644
--- a/src/ec/secp256r1.ts
+++ b/src/ec/secp256r1.ts
@@ -11,6 +11,7 @@ import {
     Utils,
     reverseByteString,
     ByteString,
+    slice,
 } from 'scrypt-ts'
 
 import { Point, Signature } from './misc'
@@ -1247,15 +1248,15 @@ export class SECP256R1 extends SmartContractLib {
     @method()
     static pubKey2Point(pubKey: PubKey): Point {
         assert(
-            pubKey.slice(0, 2) == toByteString('04'),
+            slice(pubKey, 0n, 1n) == toByteString('04'),
             'Pub key isn\'t prefixed with "04". This likely means, that it\'s not in compressed form.'
         )
         // Convert signed little endian to unsigned big endian.
         const x = Utils.fromLEUnsigned(
-            reverseByteString(pubKey.slice(2, 66), 32n)
+            reverseByteString(slice(pubKey, 1n, 33n), 32n)
         )
         const y = Utils.fromLEUnsigned(
-            reverseByteString(pubKey.slice(66, 130), 32n)
+            reverseByteString(slice(pubKey, 33n, 65n), 32n)
         )
         return {
             x: x,
diff --git a/src/schnorr.ts b/src/schnorr.ts
index f6c9dee..4e3d38e 100644
--- a/src/schnorr.ts
+++ b/src/schnorr.ts
@@ -7,6 +7,7 @@ import {
     sha256,
     SmartContractLib,
     toByteString,
+    slice,
 } from 'scrypt-ts'
 import { Point } from './ec/misc'
 import { SECP256K1 } from './ec/secp256k1'
@@ -21,9 +22,9 @@ export class Schnorr extends SmartContractLib {
         msg: ByteString,
         R: Point
     ): boolean {
-        const r: ByteString = sig.slice(0, 64) // First 32 bytes
+        const r: ByteString = slice(sig, 0n, 64n) // First 32 bytes
         const s = byteString2Int(
-            reverseByteString(sig.slice(64, 128), 32n) + toByteString('00')
+            reverseByteString(slice(sig, 32n, 64n), 32n) + toByteString('00')
         )
 
         // e = Hash(r || P || msg)