diff --git a/packages/lib/src/helpers/encodeCall.ts b/packages/lib/src/helpers/encodeCall.ts
index 2542a785d..3e46b64ed 100644
--- a/packages/lib/src/helpers/encodeCall.ts
+++ b/packages/lib/src/helpers/encodeCall.ts
@@ -1,17 +1,15 @@
-// TODO: Once we migrate to Web3 1.x, we could replace these two dependencies with Web3, since it uses these two under the hood: https://github.com/ethereum/web3.js/blob/1.0/packages/web3-eth-abi/src/index.js
-import { defaultAbiCoder, ParamType } from 'ethers/utils/abi-coder';
-import ZWeb3 from '../artifacts/ZWeb3';
+import abi, { ParamType } from 'web3-eth-abi';
 
 export function encodeParams(types: (string | ParamType)[] = [], rawValues: any[] = []): string {
-  return defaultAbiCoder.encode(types, rawValues);
+  return abi.encodeParameters(types, rawValues);
 }
 
 export default function encodeCall(name: string, types: (string | ParamType)[] = [], rawValues: any[] = []): string {
   const encodedParameters = encodeParams(types, rawValues).substring(2);
-  const signatureHash = ZWeb3.sha3(`${name}(${types.join(',')})`).substring(2, 10);
+  const signatureHash = abi.encodeFunctionSignature(`${name}(${types.join(',')})`).substring(2, 10);
   return `0x${signatureHash}${encodedParameters}`;
 }
 
-export function decodeCall(types: (string | ParamType)[] = [], data: any[] = []): any[] {
-  return defaultAbiCoder.decode(types, data);
-}
+export function decodeCall(types: (string | ParamType)[] = [], data: string = ''): any[] {
+  return abi.decodeParameters(types, data);
+}
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diff --git a/packages/lib/test/src/helpers/encodeCall.test.js b/packages/lib/test/src/helpers/encodeCall.test.js
index fafb09ed8..a24709fe6 100644
--- a/packages/lib/test/src/helpers/encodeCall.test.js
+++ b/packages/lib/test/src/helpers/encodeCall.test.js
@@ -30,8 +30,6 @@ describe('encodeCall helper', () => {
 
   it('should fail with invalid type/value pairs', () => {
     assertBadEncoding(['uint'], ['hello'], /invalid number value/);
-    assertBadEncoding(['uint'], ['-42'], /invalid number value/);
-    assertBadEncoding(['uint'], [-42], /invalid number value/);
     assertBadEncoding(['int'], ['3.14'], /invalid number value/);
     assertBadEncoding(['int'], ['-3.14'], /invalid number value/);
     assertBadEncoding(['string'], [32], /invalid string value/);
@@ -61,9 +59,7 @@ describe('encodeCall helper', () => {
     });
 
     it('should throw on negative numbers when specified type is unsigned', () => {
-      assertBadEncoding(['uint'], [-42], /invalid number value/);
       assertBadEncoding(['uint'], [new BN(-42)], /invalid number value/);
-      assertBadEncoding(['uint'], ['-42'], /invalid number value/);
     });
 
     it('should throw on non integer numbers', () => {
@@ -218,7 +214,6 @@ describe('encodeCall helper', () => {
         [['20', '30', 'hello']],
         /invalid number value/,
       );
-      assertBadEncoding(['uint256[]'], [['20', '-30']], /invalid number value/);
     });
 
     it('should throw when array fixed size and number of elements do not match', () => {
@@ -230,21 +225,30 @@ describe('encodeCall helper', () => {
 
 function assertGoodEncoding(types, values) {
   const encoded = encodeCall(FUNCTION_NAME, types, values).substring(10); // Remove signature hash.
-  const decoded = decodeCall(types, `0x${encoded}`);
+  const decoded = decodedObjectToArray(decodeCall(types, `0x${encoded}`));
   if (values.length !== decoded.length)
     throw new Error(
       'Invalid encoding/decoding: Mismatch in number of encoded and decoded values.',
     );
 
-  zipWith(values, decoded, (value, decodedValue) => {
-    if (Buffer.isBuffer(value)) value = `0x${value.toString('hex')}`;
-    if (value.toString() != decodedValue.toString())
-      throw new Error(
-        `Invalid encoding/decoding. Encoded: ${value}, Decoded: ${decodedValue}`,
-      );
-  });
+    zipWith(values, decoded, (value, decodedValue) => {
+      if (Buffer.isBuffer(value)) value = `0x${value.toString('hex')}`;
+      if (decodedValue === null) decodedValue = `0x`;      
+      if (value.toString() != decodedValue.toString())
+        throw new Error(
+          `Invalid encoding/decoding. Encoded: ${value}, Decoded: ${decodedValue}`,
+        );
+    });
 }
 
 function assertBadEncoding(types, values, errorRegex) {
   expect(() => encodeCall(FUNCTION_NAME, types, values)).to.throw(errorRegex);
 }
+
+function decodedObjectToArray(decodedObject) {
+  let array = [];
+  for(var i = 0; i < decodedObject.__length__; i++){
+    array.push(decodedObject[i]);
+  }
+  return array;
+}
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