From e8a2c453903e988ba8e3e45b63bddc4c6e8b4235 Mon Sep 17 00:00:00 2001
From: Daniel Huigens <d.huigens@protonmail.com>
Date: Thu, 1 Nov 2018 10:48:25 +0100
Subject: [PATCH] Only use Web Crypto for hashing beyond a treshold number of
 bytes

Sending data to the Web Crypto API involves some latency.
---
 src/config/config.js     | 5 +++++
 src/crypto/hash/index.js | 6 ++++--
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/src/config/config.js b/src/config/config.js
index d11b217c..8fb39185 100644
--- a/src/config/config.js
+++ b/src/config/config.js
@@ -126,6 +126,11 @@ export default {
    * @property {Boolean} use_native Use native Node.js crypto/zlib and WebCrypto APIs when available
    */
   use_native:               true,
+  /**
+   * @memberof module:config
+   * @property {Integer} min_bytes_for_web_crypto The minimum amount of bytes for which to use native WebCrypto APIs when available
+   */
+  min_bytes_for_web_crypto: 1000,
   /**
    * @memberof module:config
    * @property {Boolean} Use transferable objects between the Web Worker and main thread
diff --git a/src/crypto/hash/index.js b/src/crypto/hash/index.js
index 1d829611..bbb977b3 100644
--- a/src/crypto/hash/index.js
+++ b/src/crypto/hash/index.js
@@ -6,6 +6,7 @@
  * @requires hash.js
  * @requires web-stream-tools
  * @requires crypto/hash/md5
+ * @requires config
  * @requires util
  * @module crypto/hash
  */
@@ -18,6 +19,7 @@ import sha512 from 'hash.js/lib/hash/sha/512';
 import { ripemd160 } from 'hash.js/lib/hash/ripemd';
 import stream from 'web-stream-tools';
 import md5 from './md5';
+import config from '../../config';
 import util from '../../util';
 
 const webCrypto = util.getWebCrypto();
@@ -35,7 +37,7 @@ function node_hash(type) {
 
 function hashjs_hash(hash, webCryptoHash) {
   return async function(data) {
-    if (!util.isStream(data) && webCrypto && webCryptoHash) {
+    if (!util.isStream(data) && webCrypto && webCryptoHash && data.length >= config.min_bytes_for_web_crypto) {
       return new Uint8Array(await webCrypto.digest(webCryptoHash, data));
     }
     const hashInstance = hash();
@@ -52,7 +54,7 @@ function asmcrypto_hash(hash, webCryptoHash) {
       return stream.transform(data, value => {
         hashInstance.process(value);
       }, () => hashInstance.finish().result);
-    } else if (webCrypto && webCryptoHash) {
+    } else if (webCrypto && webCryptoHash && data.length >= config.min_bytes_for_web_crypto) {
       return new Uint8Array(await webCrypto.digest(webCryptoHash, data));
     } else {
       return hash.bytes(data);