remove buffer use to support browser

src/crypto_utils.ts

@@ -99,15 +99,25 @@ export function recoverUserKey(privateKey: Uint8Array, encryptedKeyShare0: strin
     const decryptedKeyShare0: string = decryptRSA(privateKey, encryptedKeyShare0);
     const decryptedKeyShare1: string = decryptRSA(privateKey, encryptedKeyShare1);
 
-    const bufferKeyShare0 = Buffer.from(decryptedKeyShare0, 'hex'); // 'hex' because decryptRSA is returning hex-encoded string
-    const bufferKeyShare1 = Buffer.from(decryptedKeyShare1, 'hex');
 
-    const aesKey = Buffer.alloc(bufferKeyShare0.length);
-    for (let i = 0; i < bufferKeyShare0.length; i++) {
-        aesKey[i] = bufferKeyShare0[i] ^ bufferKeyShare1[i];
+    const bufferKeyShare0 = encodeKey(decryptedKeyShare0)
+    const bufferKeyShare1 = encodeKey(decryptedKeyShare1)
+    const aesKeyBytes = new Uint8Array(BLOCK_SIZE)
+
+    for (let i = 0; i < BLOCK_SIZE; i++) {
+        aesKeyBytes[i] = bufferKeyShare0[i] ^ bufferKeyShare1[i];
+    }
+    const aesKey: Array<string> = []
+
+    let byte = ''
+
+    for (let i = 0; i < aesKeyBytes.length; i++) {
+        byte = aesKeyBytes[i].toString(HEX_BASE).padStart(2, '0') // ensure that the zero byte is represented using two digits
+
+        aesKey.push(byte)
     }
 
-    return aesKey.toString('hex');
+    return aesKey.join("")
 }