diff --git a/package.json b/package.json
index 1d08d3d..7045a0d 100644
--- a/package.json
+++ b/package.json
@@ -54,6 +54,7 @@
     "@typescript-eslint/parser": "^3.0.2",
     "babelify": "^10.0.0",
     "browserify": "^16.5.1",
+    "circomlibjs": "^0.1.7",
     "crypto": "0.0.3",
     "ethereum-cryptography": "^1.0.3",
     "ethereumjs-util": "^7.0.9",
@@ -88,6 +89,8 @@
     "plugins": [
       "@typescript-eslint/eslint-plugin"
     ],
-    "globals": ["BigInt"]
+    "globals": [
+      "BigInt"
+    ]
   }
 }
diff --git a/src/Base.ts b/src/Base.ts
index 7c2ba00..52af0b5 100644
--- a/src/Base.ts
+++ b/src/Base.ts
@@ -169,6 +169,8 @@ export class Base {
         return Buffer.from(value)
       } else if (typeof value === 'bigint') {
         return Buffer.from(value.toString(16), 'hex')
+      } else if (value instanceof Uint8Array) {
+        return Buffer.from(value.buffer)
       } else if (typeof value === 'number') {
         let s = value.toString()
         if (s.length % 2) {
@@ -193,15 +195,20 @@ export class Base {
     }
 
     if (typeof value === 'string') {
-      if (Base.isHexString(value)) {
+      if (value.startsWith('0x') && Base.isHexString(value)) {
         return BigInt('0x' + value.replace('0x', '').toString())
       }
+      return BigInt(value)
     }
 
     if (Buffer.isBuffer(value)) {
       return BigInt('0x' + value.toString('hex'))
     }
 
+    if (value instanceof Uint8Array) {
+      return BigInt(value)
+    }
+
     if (typeof value === 'number') {
       return BigInt(value)
     }
@@ -368,6 +375,10 @@ export class Base {
   protected _zip (a: any[], b: any[]): any[][] {
     return a.map((e, i) => [e, b[i]])
   }
+
+  static hexZeroPad (hexStr: string, length: number) {
+    return '0x' + hexStr.replace('0x', '').padStart(length, '0')
+  }
 }
 
 export default Base
diff --git a/test/Base.test.js b/test/Base.test.js
index 219826a..d2432f5 100644
--- a/test/Base.test.js
+++ b/test/Base.test.js
@@ -2,7 +2,7 @@ const test = require('tape')
 const { Base } = require('../dist/Base')
 
 test('bufferify', t => {
-  t.plan(5)
+  t.plan(6)
 
   const base = new Base()
   t.deepEqual(base.bufferify(''), Buffer.alloc(0))
@@ -10,25 +10,29 @@ test('bufferify', t => {
   t.deepEqual(base.bufferify('123'), Buffer.from('123', 'hex'))
   t.deepEqual(base.bufferify(Buffer.from('123')), Buffer.from('123'))
   t.deepEqual(base.bufferify(BigInt('0x123')), Buffer.from('123', 'hex'))
+  t.deepEqual(base.bufferify(new Uint8Array([123])), Buffer.from([123]))
 })
 
 test('bufferifyFn', t => {
-  t.plan(3)
+  t.plan(5)
 
   const base = new Base()
   const fn = base.bufferifyFn(value => value)
   t.deepEqual(fn('123'), Buffer.from('123', 'hex'))
   t.deepEqual(fn('0x123'), Buffer.from('123', 'hex'))
   t.deepEqual(fn('XYZ'), Buffer.from('XYZ'))
+  t.deepEqual(fn(BigInt('0x123')), Buffer.from('123', 'hex'))
+  t.deepEqual(fn(new Uint8Array([123])), Buffer.from([123]))
 })
 
 test('bigNumberify', t => {
-  t.plan(3)
+  t.plan(4)
 
   const base = new Base()
   t.deepEqual(base.bigNumberify(123), BigInt(123))
   t.deepEqual(base.bigNumberify('0x123'), BigInt('0x123'))
   t.deepEqual(base.bigNumberify(BigInt(123)), BigInt(123))
+  t.deepEqual(base.bigNumberify(new Uint8Array([123])), BigInt(123))
 })
 
 test('binarySearch', t => {
diff --git a/test/MerkleTree.test.js b/test/MerkleTree.test.js
index c1f26b0..32d5646 100644
--- a/test/MerkleTree.test.js
+++ b/test/MerkleTree.test.js
@@ -9,7 +9,7 @@ const SHA256 = require('crypto-js/sha256')
 const SHA3 = require('crypto-js/sha3')
 const sha1 = require('sha1')
 const { keccak256: ethCryptoKeccak256 } = require('ethereum-cryptography/keccak')
-const { poseidon } = require('circomlibjs')
+const { buildPoseidon } = require('circomlibjs')
 
 const { MerkleTree } = require('../')
 
@@ -1324,22 +1324,24 @@ test.skip('1M leaves keccak256', t => {
   t.false(tree.verify(proof, keccak256(`${max + 1}`), tree.getRoot()))
 })
 
-test('poseidon hash', t => {
+test('poseidon hash', async t => {
   t.plan(4)
 
-  const _poseidon = (elements) => {
-    const bigInts = elements.map(MerkleTree.bigNumberify)
-    return Buffer.from(poseidon(bigInts).toString(16), 'hex')
+  const _poseidon = await buildPoseidon()
+  const poseidonHash = (inputs) => {
+    const hash = _poseidon(inputs.map(MerkleTree.bigNumberify))
+    const bn = MerkleTree.bigNumberify(_poseidon.F.toString(hash))
+    return MerkleTree.bufferify(bn)
   }
 
-  const result1 = _poseidon([1, 2].map(MerkleTree.bufferify))
+  const result1 = poseidonHash([1, 2])
   t.equal(result1.toString('hex'), '115cc0f5e7d690413df64c6b9662e9cf2a3617f2743245519e19607a4417189a')
 
-  const result2 = _poseidon([1, 2, 3, 4].map(MerkleTree.bufferify))
+  const result2 = poseidonHash([1, 2, 3, 4])
   t.equal(result2.toString('hex'), '299c867db6c1fdd79dcefa40e4510b9837e60ebb1ce0663dbaa525df65250465')
 
-  const leaves = [1, 2, 3, 4].map(x => _poseidon([x]))
-  const tree = new MerkleTree(leaves, _poseidon, {
+  const leaves = [1, 2, 3, 4].map(x => poseidonHash([x]))
+  const tree = new MerkleTree(leaves, poseidonHash, {
     concatFn: (hashes) => hashes
   })
   t.equal(tree.getHexRoot(), '0xd24e045226875e22b37ce607ea2af7a9fbb137ee128caa0ce3663615350245')