From: Chris Duncan <chris@zoso.dev>
Date: Sat, 29 Aug 2026 05:53:43 +0000 (-0700)
Subject: Return pointer to A and pass it into relaxed verify.
X-Git-Url: https://git.codecow.com/?a=commitdiff_plain;h=858e7168726370fbeddbc1a0d0b9f927db878b22;p=nano25519.git

Return pointer to A and pass it into relaxed verify.
---

diff --git a/src/assembly/crypto_verify.ts b/src/assembly/crypto_verify.ts
index 8b3e9b2..d2876f5 100644
--- a/src/assembly/crypto_verify.ts
+++ b/src/assembly/crypto_verify.ts
@@ -3,7 +3,6 @@
 
 import { BLOCKHASH_BYTELENGTH, KEY_BYTELENGTH } from '.'
 import { Blake2b } from './blake2b'
-import { fe_0 } from './fe'
 import { ge_double_scalarmult_vartime_to_p3, ge_frombytes, ge_frombytes_negate_vartime, ge_has_small_order, ge_is_canonical } from './ge'
 import { ge_p3, ge_p3_tobytes, ge_sub_p3 } from './p'
 import { sc_is_canonical, sc_reduce } from './sc'
@@ -23,15 +22,12 @@ const check_r = new StaticArray<u8>(32)
 
 /**
  * Verify public key `pub` can be decoded.
- * @returns -1 if public key fails to decode, else return 0
+ * @returns 0 if public key fails to decode, else return pointer to A
  */
-export function crypto_verify_decodepubkey (pub: StaticArray<u8>): i32 {
-	fe_0(A.X)
-	fe_0(A.Y)
-	fe_0(A.Z)
-	fe_0(A.T)
+export function crypto_verify_decodepubkey (pub: StaticArray<u8>): usize {
 	// fail if public key cannot be decoded
-	return ge_frombytes_negate_vartime(A, pub)
+	if (ge_frombytes_negate_vartime(A, pub) != 0) return 0
+	return changetype<usize>(A)
 }
 
 /**
@@ -47,7 +43,7 @@ export function crypto_verify_decodepubkey (pub: StaticArray<u8>): i32 {
  * set `A` for the scalar multiplication step before checking `sB = R + hA`.
  * @returns -1 if signature fails to verify, else return 0 if signature is good
  */
-export function crypto_verify_relaxed (s: StaticArray<u8>, M: StaticArray<u8>, pub: StaticArray<u8>): i32 {
+export function crypto_verify_relaxed (s: StaticArray<u8>, M: StaticArray<u8>, A: usize, pub: StaticArray<u8>): i32 {
 
 	// fail if private scalar `S` is out of range (`2²⁵³ ≤ S`)
 	if ((s[63] & 224) != 0) return -1
@@ -61,7 +57,7 @@ export function crypto_verify_relaxed (s: StaticArray<u8>, M: StaticArray<u8>, p
 	blake2b.init().update(s, 32).update(pub, KEY_BYTELENGTH).update(M, BLOCKHASH_BYTELENGTH).digest(h)
 	sc_reduce(h)
 
-	ge_double_scalarmult_vartime_to_p3(sb_ah, h, A, S)
+	ge_double_scalarmult_vartime_to_p3(sb_ah, h, changetype<ge_p3>(A), S)
 	ge_p3_tobytes(check_r, sb_ah)
 
 	return equalbytes(s, check_r, 32) - 1
@@ -80,7 +76,7 @@ export function crypto_verify_strict (s: StaticArray<u8>, M: StaticArray<u8>, ml
 	if (!ge_is_canonical(pub)) return -1
 
 	// fail if public key cannot be decoded
-	if (crypto_verify_decodepubkey(pub) != 0) return -1
+	if (ge_frombytes_negate_vartime(A, pub) != 0) return -1
 
 	// fail if public key `k` is small order
 	if (ge_has_small_order(A) != 0) return -1
diff --git a/src/assembly/index.ts b/src/assembly/index.ts
index 01a5db9..f8ed6c6 100644
--- a/src/assembly/index.ts
+++ b/src/assembly/index.ts
@@ -217,16 +217,16 @@ export function verify_blocks (count: i32): void {
 	INPUT_PUB.fill(0)
 
 	// Verify public key before proceeding with signature verification
-	if (crypto_verify_decodepubkey(pub) == 0) {
-
+	const A = crypto_verify_decodepubkey(pub)
+	if (A != 0) {
 		// Iterate over block signature/hash pairs
-		for (let i = 0, ptr = changetype<usize>(INPUT_MSG); i < count; i++, ptr += 96) {
+		for (let i = 0, ptr = changetype<usize>(INPUT_MSG); i < count; i++, ptr += SIGNEDBLOCK_BYTELENGTH) {
 			// Copy block signature/hash from message buffer to locals
 			memory.copy(changetype<usize>(sig), ptr, SIGNATURE_BYTELENGTH)
 			memory.copy(changetype<usize>(h), ptr + SIGNATURE_BYTELENGTH, BLOCKHASH_BYTELENGTH)
 
 			// Verify hash and signature, then write result to output buffer
-			OUTPUT_VERIFY[i] = u8(crypto_verify_relaxed(sig, h, pub))
+			OUTPUT_VERIFY[i] = u8(crypto_verify_relaxed(sig, h, A, pub))
 		}
 	}