ethereumjs · jochem-brouwer · Mar 5, 2025 · Apr 19, 2025 · Apr 19, 2025 · Apr 19, 2025
diff --git a/packages/evm/src/precompiles/bls12_381/nbl/src/_shortw_utils.ts b/packages/evm/src/precompiles/bls12_381/nbl/src/_shortw_utils.ts
@@ -0,0 +1,30 @@
+/**
+ * Utilities for short weierstrass curves, combined with noble-hashes.
+ * @module
+ */
+/*! noble-curves - MIT License (c) 2022 Paul Miller (paulmillr.com) */
+import { hmac } from '@noble/hashes/hmac'
+import { concatBytes, randomBytes } from '@noble/hashes/utils'
+import type { CHash } from './abstract/utils.ts'
+import { type CurveFn, type CurveType, weierstrass } from './abstract/weierstrass.ts'
+
+/** connects noble-curves to noble-hashes */
+export function getHash(hash: CHash): {
+  hash: CHash
+  hmac: (key: Uint8Array, ...msgs: Uint8Array[]) => Uint8Array
+  randomBytes: typeof randomBytes
+} {
+  return {
+    hash,
+    hmac: (key: Uint8Array, ...msgs: Uint8Array[]) => hmac(hash, key, concatBytes(...msgs)),
+    randomBytes,
+  }
+}
+/** Same API as @noble/hashes, with ability to create curve with custom hash */
+export type CurveDef = Readonly<Omit<CurveType, 'hash' | 'hmac' | 'randomBytes'>>
+export type CurveFnWithCreate = CurveFn & { create: (hash: CHash) => CurveFn }
+
+export function createCurve(curveDef: CurveDef, defHash: CHash): CurveFnWithCreate {
+  const create = (hash: CHash): CurveFn => weierstrass({ ...curveDef, ...getHash(hash) })
+  return { ...create(defHash), create }
+}