diff --git a/package.json b/package.json
index 4ccf1d8..44943ba 100644
--- a/package.json
+++ b/package.json
@@ -59,6 +59,8 @@
     "@types/bn.js": "^4.11.4",
     "assert": "^1.4.1",
     "bn.js": "^4.11.8",
-    "js-sha256": "^0.9.0"
+    "farmhash": "^2.1.0",
+    "js-sha256": "^0.9.0",
+    "lru-cache": "^5.1.1"
   }
 }
diff --git a/src/cache.ts b/src/cache.ts
new file mode 100644
index 0000000..703e1db
--- /dev/null
+++ b/src/cache.ts
@@ -0,0 +1,6 @@
+import LRU from "lru-cache";
+
+const defaultCache = new LRU(2000);
+
+// cache singleton
+export let cache = defaultCache;
diff --git a/src/hash.ts b/src/hash.ts
index f659f72..ac330e5 100644
--- a/src/hash.ts
+++ b/src/hash.ts
@@ -1,9 +1,28 @@
 /** @module ssz */
 import { sha256 } from "js-sha256";
+import farmhash from "farmhash";
+
+import { cache } from "./cache";
+
+/** @ignore */
+function _hash(input: Buffer): Buffer {
+  return Buffer.from(sha256.update(input).arrayBuffer());
+}
 
 /**
  * Hash used for hashTreeRoot
  */
-export function hash(...inputs: Buffer[]): Buffer {
-  return Buffer.from(inputs.reduce((acc, i) => acc.update(i), sha256.create()).arrayBuffer());
+export function hash(input: Buffer): Buffer {
+  if (cache) {
+    const cacheInput = farmhash.hash32(input);
+    const cached = cache.get(cacheInput);
+    if (cached) {
+      return cached;
+    }
+    const result = _hash(input);
+    cache.set(cacheInput, result);
+    return result;
+  } else {
+    return _hash(input);
+  }
 }
diff --git a/src/util/hash.ts b/src/util/hash.ts
index 8a9b043..df76b96 100644
--- a/src/util/hash.ts
+++ b/src/util/hash.ts
@@ -58,7 +58,7 @@ export function merkleize(chunks: Buffer[]): Buffer {
   }
   while (chunks.length > 1) {
     for (let i = 0; i < chunks.length; i += 2) {
-      chunks[i / 2] = hash(chunks[i], chunks[i + 1]);
+      chunks[i / 2] = hash(Buffer.concat([chunks[i], chunks[i + 1]]));
     }
     chunks.splice(chunks.length / 2, chunks.length / 2);
   }
@@ -69,5 +69,5 @@ export function merkleize(chunks: Buffer[]): Buffer {
 export function mixInLength(root: Buffer, length: number): Buffer {
   const lengthBuf = Buffer.alloc(32);
   lengthBuf.writeUIntLE(length, 0, 6);
-  return hash(root, lengthBuf);
+  return hash(Buffer.concat([root, lengthBuf]));
 }
diff --git a/yarn.lock b/yarn.lock
index 05e4c15..9bf0993 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -1033,6 +1033,13 @@ binary-extensions@^1.0.0:
   version "1.13.1"
   resolved "https://registry.yarnpkg.com/binary-extensions/-/binary-extensions-1.13.1.tgz#598afe54755b2868a5330d2aff9d4ebb53209b65"
 
+bl@^1.0.0:
+  version "1.2.2"
+  resolved "https://registry.yarnpkg.com/bl/-/bl-1.2.2.tgz#a160911717103c07410cef63ef51b397c025af9c"
+  dependencies:
+    readable-stream "^2.3.5"
+    safe-buffer "^5.1.1"
+
 bluebird@^3.5.3:
   version "3.5.4"
   resolved "https://registry.yarnpkg.com/bluebird/-/bluebird-3.5.4.tgz#d6cc661595de30d5b3af5fcedd3c0b3ef6ec5714"
@@ -1132,6 +1139,21 @@ browserslist@^4.5.2, browserslist@^4.5.4:
     electron-to-chromium "^1.3.124"
     node-releases "^1.1.14"
 
+buffer-alloc-unsafe@^1.1.0:
+  version "1.1.0"
+  resolved "https://registry.yarnpkg.com/buffer-alloc-unsafe/-/buffer-alloc-unsafe-1.1.0.tgz#bd7dc26ae2972d0eda253be061dba992349c19f0"
+
+buffer-alloc@^1.2.0:
+  version "1.2.0"
+  resolved "https://registry.yarnpkg.com/buffer-alloc/-/buffer-alloc-1.2.0.tgz#890dd90d923a873e08e10e5fd51a57e5b7cce0ec"
+  dependencies:
+    buffer-alloc-unsafe "^1.1.0"
+    buffer-fill "^1.0.0"
+
+buffer-fill@^1.0.0:
+  version "1.0.0"
+  resolved "https://registry.yarnpkg.com/buffer-fill/-/buffer-fill-1.0.0.tgz#f8f78b76789888ef39f205cd637f68e702122b2c"
+
 buffer-from@^1.0.0:
   version "1.1.1"
   resolved "https://registry.yarnpkg.com/buffer-from/-/buffer-from-1.1.1.tgz#32713bc028f75c02fdb710d7c7bcec1f2c6070ef"
@@ -1251,7 +1273,7 @@ chokidar@^2.0.2, chokidar@^2.0.4:
   optionalDependencies:
     fsevents "^1.2.7"
 
-chownr@^1.1.1:
+chownr@^1.0.1, chownr@^1.1.1:
   version "1.1.1"
   resolved "https://registry.yarnpkg.com/chownr/-/chownr-1.1.1.tgz#54726b8b8fff4df053c42187e801fb4412df1494"
 
@@ -1512,6 +1534,12 @@ decode-uri-component@^0.2.0:
   version "0.2.0"
   resolved "https://registry.yarnpkg.com/decode-uri-component/-/decode-uri-component-0.2.0.tgz#eb3913333458775cb84cd1a1fae062106bb87545"
 
+decompress-response@^3.3.0:
+  version "3.3.0"
+  resolved "https://registry.yarnpkg.com/decompress-response/-/decompress-response-3.3.0.tgz#80a4dd323748384bfa248083622aedec982adff3"
+  dependencies:
+    mimic-response "^1.0.0"
+
 deep-eql@^3.0.1:
   version "3.0.1"
   resolved "https://registry.yarnpkg.com/deep-eql/-/deep-eql-3.0.1.tgz#dfc9404400ad1c8fe023e7da1df1c147c4b444df"
@@ -1566,7 +1594,7 @@ detect-file@^1.0.0:
   version "1.0.0"
   resolved "https://registry.yarnpkg.com/detect-file/-/detect-file-1.0.0.tgz#f0d66d03672a825cb1b73bdb3fe62310c8e552b7"
 
-detect-libc@^1.0.2:
+detect-libc@^1.0.2, detect-libc@^1.0.3:
   version "1.0.3"
   resolved "https://registry.yarnpkg.com/detect-libc/-/detect-libc-1.0.3.tgz#fa137c4bd698edf55cd5cd02ac559f91a4c4ba9b"
 
@@ -1792,6 +1820,10 @@ expand-brackets@^2.1.4:
     snapdragon "^0.8.1"
     to-regex "^3.0.1"
 
+expand-template@^1.0.2:
+  version "1.1.1"
+  resolved "https://registry.yarnpkg.com/expand-template/-/expand-template-1.1.1.tgz#981f188c0c3a87d2e28f559bc541426ff94f21dd"
+
 expand-tilde@^2.0.0, expand-tilde@^2.0.2:
   version "2.0.2"
   resolved "https://registry.yarnpkg.com/expand-tilde/-/expand-tilde-2.0.2.tgz#97e801aa052df02454de46b02bf621642cdc8502"
@@ -1832,6 +1864,13 @@ extglob@^2.0.4:
     snapdragon "^0.8.1"
     to-regex "^3.0.1"
 
+farmhash@^2.1.0:
+  version "2.1.0"
+  resolved "https://registry.yarnpkg.com/farmhash/-/farmhash-2.1.0.tgz#134adf04ce7e9910bc387596598223775c120b8b"
+  dependencies:
+    nan "^2.10.0"
+    prebuild-install "^2.5.3"
+
 fast-deep-equal@^2.0.1:
   version "2.0.1"
   resolved "https://registry.yarnpkg.com/fast-deep-equal/-/fast-deep-equal-2.0.1.tgz#7b05218ddf9667bf7f370bf7fdb2cb15fdd0aa49"
@@ -1935,6 +1974,10 @@ from2@^2.1.0:
     inherits "^2.0.1"
     readable-stream "^2.0.0"
 
+fs-constants@^1.0.0:
+  version "1.0.0"
+  resolved "https://registry.yarnpkg.com/fs-constants/-/fs-constants-1.0.0.tgz#6be0de9be998ce16af8afc24497b9ee9b7ccd9ad"
+
 fs-extra@^7.0.0:
   version "7.0.1"
   resolved "https://registry.yarnpkg.com/fs-extra/-/fs-extra-7.0.1.tgz#4f189c44aa123b895f722804f55ea23eadc348e9"
@@ -2008,6 +2051,10 @@ get-value@^2.0.3, get-value@^2.0.6:
   version "2.0.6"
   resolved "https://registry.yarnpkg.com/get-value/-/get-value-2.0.6.tgz#dc15ca1c672387ca76bd37ac0a395ba2042a2c28"
 
+github-from-package@0.0.0:
+  version "0.0.0"
+  resolved "https://registry.yarnpkg.com/github-from-package/-/github-from-package-0.0.0.tgz#97fb5d96bfde8973313f20e8288ef9a167fa64ce"
+
 glob-parent@^3.1.0:
   version "3.1.0"
   resolved "https://registry.yarnpkg.com/glob-parent/-/glob-parent-3.1.0.tgz#9e6af6299d8d3bd2bd40430832bd113df906c5ae"
@@ -2696,6 +2743,10 @@ mimic-fn@^2.0.0:
   version "2.1.0"
   resolved "https://registry.yarnpkg.com/mimic-fn/-/mimic-fn-2.1.0.tgz#7ed2c2ccccaf84d3ffcb7a69b57711fc2083401b"
 
+mimic-response@^1.0.0:
+  version "1.0.1"
+  resolved "https://registry.yarnpkg.com/mimic-response/-/mimic-response-1.0.1.tgz#4923538878eef42063cb8a3e3b0798781487ab1b"
+
 minimalistic-assert@^1.0.0, minimalistic-assert@^1.0.1:
   version "1.0.1"
   resolved "https://registry.yarnpkg.com/minimalistic-assert/-/minimalistic-assert-1.0.1.tgz#2e194de044626d4a10e7f7fbc00ce73e83e4d5c7"
@@ -2802,6 +2853,10 @@ mute-stream@0.0.7:
   version "0.0.7"
   resolved "https://registry.yarnpkg.com/mute-stream/-/mute-stream-0.0.7.tgz#3075ce93bc21b8fab43e1bc4da7e8115ed1e7bab"
 
+nan@^2.10.0:
+  version "2.14.0"
+  resolved "https://registry.yarnpkg.com/nan/-/nan-2.14.0.tgz#7818f722027b2459a86f0295d434d1fc2336c52c"
+
 nan@^2.12.1:
   version "2.13.2"
   resolved "https://registry.yarnpkg.com/nan/-/nan-2.13.2.tgz#f51dc7ae66ba7d5d55e1e6d4d8092e802c9aefe7"
@@ -2842,6 +2897,12 @@ nice-try@^1.0.4:
   version "1.0.5"
   resolved "https://registry.yarnpkg.com/nice-try/-/nice-try-1.0.5.tgz#a3378a7696ce7d223e88fc9b764bd7ef1089e366"
 
+node-abi@^2.2.0:
+  version "2.9.0"
+  resolved "https://registry.yarnpkg.com/node-abi/-/node-abi-2.9.0.tgz#ae4075b298dab2d92dd1e22c48ccc7ffd7f06200"
+  dependencies:
+    semver "^5.4.1"
+
 node-fetch@^2.2.0:
   version "2.3.0"
   resolved "https://registry.yarnpkg.com/node-fetch/-/node-fetch-2.3.0.tgz#1a1d940bbfb916a1d3e0219f037e89e71f8c5fa5"
@@ -2899,6 +2960,10 @@ node-releases@^1.1.14:
   dependencies:
     semver "^5.3.0"
 
+noop-logger@^0.1.1:
+  version "0.1.1"
+  resolved "https://registry.yarnpkg.com/noop-logger/-/noop-logger-0.1.1.tgz#94a2b1633c4f1317553007d8966fd0e841b6a4c2"
+
 nopt@^4.0.1:
   version "4.0.1"
   resolved "https://registry.yarnpkg.com/nopt/-/nopt-4.0.1.tgz#d0d4685afd5415193c8c7505602d0d17cd64474d"
@@ -2942,7 +3007,7 @@ npm-run-path@^2.0.0:
   dependencies:
     path-key "^2.0.0"
 
-npmlog@^4.0.2:
+npmlog@^4.0.1, npmlog@^4.0.2:
   version "4.1.2"
   resolved "https://registry.yarnpkg.com/npmlog/-/npmlog-4.1.2.tgz#08a7f2a8bf734604779a9efa4ad5cc717abb954b"
   dependencies:
@@ -3226,6 +3291,26 @@ posix-character-classes@^0.1.0:
   version "0.1.1"
   resolved "https://registry.yarnpkg.com/posix-character-classes/-/posix-character-classes-0.1.1.tgz#01eac0fe3b5af71a2a6c02feabb8c1fef7e00eab"
 
+prebuild-install@^2.5.3:
+  version "2.5.3"
+  resolved "https://registry.yarnpkg.com/prebuild-install/-/prebuild-install-2.5.3.tgz#9f65f242782d370296353710e9bc843490c19f69"
+  dependencies:
+    detect-libc "^1.0.3"
+    expand-template "^1.0.2"
+    github-from-package "0.0.0"
+    minimist "^1.2.0"
+    mkdirp "^0.5.1"
+    node-abi "^2.2.0"
+    noop-logger "^0.1.1"
+    npmlog "^4.0.1"
+    os-homedir "^1.0.1"
+    pump "^2.0.1"
+    rc "^1.1.6"
+    simple-get "^2.7.0"
+    tar-fs "^1.13.0"
+    tunnel-agent "^0.6.0"
+    which-pm-runs "^1.0.0"
+
 prelude-ls@~1.1.2:
   version "1.1.2"
   resolved "https://registry.yarnpkg.com/prelude-ls/-/prelude-ls-1.1.2.tgz#21932a549f5e52ffd9a827f570e04be62a97da54"
@@ -3269,7 +3354,14 @@ public-encrypt@^4.0.0:
     randombytes "^2.0.1"
     safe-buffer "^5.1.2"
 
-pump@^2.0.0:
+pump@^1.0.0:
+  version "1.0.3"
+  resolved "https://registry.yarnpkg.com/pump/-/pump-1.0.3.tgz#5dfe8311c33bbf6fc18261f9f34702c47c08a954"
+  dependencies:
+    end-of-stream "^1.1.0"
+    once "^1.3.1"
+
+pump@^2.0.0, pump@^2.0.1:
   version "2.0.1"
   resolved "https://registry.yarnpkg.com/pump/-/pump-2.0.1.tgz#12399add6e4cf7526d973cbc8b5ce2e2908b3909"
   dependencies:
@@ -3324,7 +3416,7 @@ randomfill@^1.0.3:
     randombytes "^2.0.5"
     safe-buffer "^5.1.0"
 
-rc@^1.2.7:
+rc@^1.1.6, rc@^1.2.7:
   version "1.2.8"
   resolved "https://registry.yarnpkg.com/rc/-/rc-1.2.8.tgz#cd924bf5200a075b83c188cd6b9e211b7fc0d3ed"
   dependencies:
@@ -3348,7 +3440,7 @@ read-pkg@^3.0.0:
     normalize-package-data "^2.3.2"
     path-type "^3.0.0"
 
-"readable-stream@1 || 2", readable-stream@^2.0.0, readable-stream@^2.0.1, readable-stream@^2.0.2, readable-stream@^2.0.6, readable-stream@^2.1.5, readable-stream@^2.2.2, readable-stream@^2.3.3, readable-stream@^2.3.6, readable-stream@~2.3.6:
+"readable-stream@1 || 2", readable-stream@^2.0.0, readable-stream@^2.0.1, readable-stream@^2.0.2, readable-stream@^2.0.6, readable-stream@^2.1.5, readable-stream@^2.2.2, readable-stream@^2.3.0, readable-stream@^2.3.3, readable-stream@^2.3.5, readable-stream@^2.3.6, readable-stream@~2.3.6:
   version "2.3.6"
   resolved "https://registry.yarnpkg.com/readable-stream/-/readable-stream-2.3.6.tgz#b11c27d88b8ff1fbe070643cf94b0c79ae1b0aaf"
   dependencies:
@@ -3636,6 +3728,18 @@ signal-exit@^3.0.0, signal-exit@^3.0.2:
   version "3.0.2"
   resolved "https://registry.yarnpkg.com/signal-exit/-/signal-exit-3.0.2.tgz#b5fdc08f1287ea1178628e415e25132b73646c6d"
 
+simple-concat@^1.0.0:
+  version "1.0.0"
+  resolved "https://registry.yarnpkg.com/simple-concat/-/simple-concat-1.0.0.tgz#7344cbb8b6e26fb27d66b2fc86f9f6d5997521c6"
+
+simple-get@^2.7.0:
+  version "2.8.1"
+  resolved "https://registry.yarnpkg.com/simple-get/-/simple-get-2.8.1.tgz#0e22e91d4575d87620620bc91308d57a77f44b5d"
+  dependencies:
+    decompress-response "^3.3.0"
+    once "^1.3.1"
+    simple-concat "^1.0.0"
+
 slash@^2.0.0:
   version "2.0.0"
   resolved "https://registry.yarnpkg.com/slash/-/slash-2.0.0.tgz#de552851a1759df3a8f206535442f5ec4ddeab44"
@@ -3888,6 +3992,27 @@ tapable@^1.0.0, tapable@^1.1.0:
   version "1.1.3"
   resolved "https://registry.yarnpkg.com/tapable/-/tapable-1.1.3.tgz#a1fccc06b58db61fd7a45da2da44f5f3a3e67ba2"
 
+tar-fs@^1.13.0:
+  version "1.16.3"
+  resolved "https://registry.yarnpkg.com/tar-fs/-/tar-fs-1.16.3.tgz#966a628841da2c4010406a82167cbd5e0c72d509"
+  dependencies:
+    chownr "^1.0.1"
+    mkdirp "^0.5.1"
+    pump "^1.0.0"
+    tar-stream "^1.1.2"
+
+tar-stream@^1.1.2:
+  version "1.6.2"
+  resolved "https://registry.yarnpkg.com/tar-stream/-/tar-stream-1.6.2.tgz#8ea55dab37972253d9a9af90fdcd559ae435c555"
+  dependencies:
+    bl "^1.0.0"
+    buffer-alloc "^1.2.0"
+    end-of-stream "^1.0.0"
+    fs-constants "^1.0.0"
+    readable-stream "^2.3.0"
+    to-buffer "^1.1.1"
+    xtend "^4.0.0"
+
 tar@^4:
   version "4.4.8"
   resolved "https://registry.yarnpkg.com/tar/-/tar-4.4.8.tgz#b19eec3fde2a96e64666df9fdb40c5ca1bc3747d"
@@ -3969,6 +4094,10 @@ to-arraybuffer@^1.0.0:
   version "1.0.1"
   resolved "https://registry.yarnpkg.com/to-arraybuffer/-/to-arraybuffer-1.0.1.tgz#7d229b1fcc637e466ca081180836a7aabff83f43"
 
+to-buffer@^1.1.1:
+  version "1.1.1"
+  resolved "https://registry.yarnpkg.com/to-buffer/-/to-buffer-1.1.1.tgz#493bd48f62d7c43fcded313a03dcadb2e1213a80"
+
 to-fast-properties@^2.0.0:
   version "2.0.0"
   resolved "https://registry.yarnpkg.com/to-fast-properties/-/to-fast-properties-2.0.0.tgz#dc5e698cbd079265bc73e0377681a4e4e83f616e"
@@ -4013,6 +4142,12 @@ tty-browserify@0.0.0:
   version "0.0.0"
   resolved "https://registry.yarnpkg.com/tty-browserify/-/tty-browserify-0.0.0.tgz#a157ba402da24e9bf957f9aa69d524eed42901a6"
 
+tunnel-agent@^0.6.0:
+  version "0.6.0"
+  resolved "https://registry.yarnpkg.com/tunnel-agent/-/tunnel-agent-0.6.0.tgz#27a5dea06b36b04a0a9966774b290868f0fc40fd"
+  dependencies:
+    safe-buffer "^5.0.1"
+
 type-check@~0.3.2:
   version "0.3.2"
   resolved "https://registry.yarnpkg.com/type-check/-/type-check-0.3.2.tgz#5884cab512cf1d355e3fb784f30804b2b520db72"
@@ -4253,6 +4388,10 @@ which-module@^2.0.0:
   version "2.0.0"
   resolved "https://registry.yarnpkg.com/which-module/-/which-module-2.0.0.tgz#d9ef07dce77b9902b8a3a8fa4b31c3e3f7e6e87a"
 
+which-pm-runs@^1.0.0:
+  version "1.0.0"
+  resolved "https://registry.yarnpkg.com/which-pm-runs/-/which-pm-runs-1.0.0.tgz#670b3afbc552e0b55df6b7780ca74615f23ad1cb"
+
 which@^1.2.14, which@^1.2.9, which@^1.3.0:
   version "1.3.1"
   resolved "https://registry.yarnpkg.com/which/-/which-1.3.1.tgz#a45043d54f5805316da8d62f9f50918d3da70b0a"