Remove sha hash optionality.

lib/index.js

@@ -7,8 +7,6 @@ import {name} from './name.js';
 import {requiredAlgorithm} from './requiredAlgorithm.js';
 import {sha} from './sha.js';
 
-const REQUIRED_HASH_ALGORITHM = 'SHA-256';
-
 export function createSignCryptosuite() {
   return {
     name,
@@ -41,15 +39,14 @@ function _createVerifyDataFn(modifyProofOptionsAndDocument) {
     // determine digest algorithm from key algorithm
     modifyProofOptionsAndDocument({proof, document});
 
-    const algorithm = REQUIRED_HASH_ALGORITHM;
     // await both jcs proof hash and jcs document hash
     const [proofHash, docHash] = await Promise.all([
       // canonize and hash proof
       _canonizeProof(proof, {cryptosuite}).then(
-        jcsProofOptions => sha({algorithm, string: jcsProofOptions})),
+        jcsProofOptions => sha({string: jcsProofOptions})),
       // canonize and hash document
       cryptosuite.canonize(document).then(
-        jcsDocument => sha({algorithm, string: jcsDocument}))
+        jcsDocument => sha({string: jcsDocument}))
     ]);
 
     // concatenate hash of jcs proof options and hash of c14n document

lib/sha.js

@@ -3,16 +3,17 @@
  */
 import crypto from 'node:crypto';
 
+const REQUIRED_HASH_ALGORITHM = 'SHA-256';
+
 /**
  * Hashes a string of data using SHA-256 or SHA-384.
  *
  * @param {object} options - The options to use.
- * @param {string} options.algorithm - The algorithm to use.
  * @param {string} options.string - The string to hash.
  *
  * @returns {Uint8Array} The hash digest.
  */
-export async function sha({algorithm, string}) {
-  algorithm = algorithm === 'SHA-256' ? 'sha256' : 'sha384';
+export async function sha({string}) {
+  const algorithm = REQUIRED_HASH_ALGORITHM;
   return new Uint8Array(crypto.createHash(algorithm).update(string).digest());
 }