diff --git a/package.json b/package.json
index 65ba239..ff3441b 100644
--- a/package.json
+++ b/package.json
@@ -39,9 +39,8 @@
     "benchmark": "node -r ./.babel-register test/benchmarks"
   },
   "dependencies": {
-    "@chainsafe/bls-keygen": "^0.2.0",
-    "@chainsafe/eth2-bls-wasm": "^0.5.0",
-    "assert": "^1.4.1"
+    "@chainsafe/bls-keygen": "^0.3.0",
+    "@chainsafe/eth2-bls-wasm": "^0.5.0"
   },
   "devDependencies": {
     "@babel/cli": "^7.8.4",
@@ -78,5 +77,8 @@
     "typescript": "^3.7.5",
     "webpack": "^4.30.0",
     "webpack-cli": "^3.3.2"
+  },
+  "resolutions": {
+    "v8-profiler-next": "1.3.0"
   }
 }
diff --git a/src/helpers/index.ts b/src/helpers/index.ts
new file mode 100644
index 0000000..037b90c
--- /dev/null
+++ b/src/helpers/index.ts
@@ -0,0 +1 @@
+export * from "./utils";
\ No newline at end of file
diff --git a/src/helpers/utils.ts b/src/helpers/utils.ts
index 7430d7d..1f768bc 100644
--- a/src/helpers/utils.ts
+++ b/src/helpers/utils.ts
@@ -1,17 +1,9 @@
-import assert from "assert";
 import {PUBLIC_KEY_LENGTH, SIGNATURE_LENGTH} from "../constants";
 
-/**
- * Pads byte array with zeroes on left side up to desired length.
- * Throws if source is larger than desired result.
- * @param source
- * @param length
- */
-export function padLeft(source: Uint8Array, length: number): Buffer {
-  assert(source.length <= length, "Given array must be smaller or equal to desired array size");
-  const result = Buffer.alloc(length, 0);
-  result.set(source, length - source.length);
-  return result;
+export function assert(condition: unknown, message = "Assertion failed"): asserts condition {
+  if(!condition) {
+    throw new Error(message)
+  }
 }
 
 export const EMPTY_PUBLIC_KEY = Buffer.alloc(PUBLIC_KEY_LENGTH);
diff --git a/src/index.ts b/src/index.ts
index b398620..6dfc0ac 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -3,7 +3,7 @@ import {PrivateKey} from "./privateKey";
 import {PublicKey} from "./publicKey";
 import {Signature} from "./signature";
 import {PUBLIC_KEY_LENGTH} from "./constants";
-import assert from "assert";
+import {assert} from "./helpers";
 
 export {Keypair, PrivateKey, PublicKey, Signature};
 
diff --git a/src/privateKey.ts b/src/privateKey.ts
index deb8029..dfce61e 100644
--- a/src/privateKey.ts
+++ b/src/privateKey.ts
@@ -1,5 +1,5 @@
 import {SECRET_KEY_LENGTH} from "./constants";
-import assert from "assert";
+import {assert} from "./helpers";
 import {SecretKeyType} from "@chainsafe/eth2-bls-wasm";
 import {generateRandomSecretKey} from "@chainsafe/bls-keygen";
 import {getContext} from "./context";
diff --git a/src/publicKey.ts b/src/publicKey.ts
index c994489..725ed76 100644
--- a/src/publicKey.ts
+++ b/src/publicKey.ts
@@ -2,7 +2,7 @@ import {PrivateKey} from "./privateKey";
 import {PublicKeyType} from "@chainsafe/eth2-bls-wasm";
 import {getContext} from "./context";
 import {PUBLIC_KEY_LENGTH} from "./constants";
-import assert from "assert";
+import {assert} from "./helpers";
 import {Signature} from "./signature";
 import {EMPTY_PUBLIC_KEY} from "./helpers/utils";
 
diff --git a/src/signature.ts b/src/signature.ts
index 08c38e6..897c96b 100644
--- a/src/signature.ts
+++ b/src/signature.ts
@@ -1,4 +1,4 @@
-import assert from "assert";
+import {assert} from "./helpers";
 import {FP_POINT_LENGTH} from "./constants";
 import {SignatureType} from "@chainsafe/eth2-bls-wasm";
 import {getContext} from "./context";
diff --git a/yarn.lock b/yarn.lock
index 296f5d6..3c0a153 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -799,26 +799,25 @@
     "@assemblyscript/loader" "^0.9.2"
     buffer "^5.4.3"
 
-"@chainsafe/bls-hd-key@^0.1.0":
-  version "0.1.0"
-  resolved "https://registry.yarnpkg.com/@chainsafe/bls-hd-key/-/bls-hd-key-0.1.0.tgz#5e51de16801f4b4b421e418f0d1ef0692df0c585"
-  integrity sha512-VZj+Ml4YTPz+d/K2n9q/9bLlIJnTr/xdAC5w1eCvIFtcQrZCY1Zw+bCcXKX1q6sbZpO9xhyuoepJzJX9VkMPqw==
+"@chainsafe/bls-hd-key@^0.2.0":
+  version "0.2.0"
+  resolved "https://registry.yarnpkg.com/@chainsafe/bls-hd-key/-/bls-hd-key-0.2.0.tgz#90aaf030150de64099e1fb27582b27bbe5ce5309"
+  integrity sha512-ps10jd99UWcm1qPo4spD/6hxFor9fsDgB0s2wJuFKqPdM2R+4LCowhv5kdGgGs3VIN1H8l+CgO08yC7X0WlBDQ==
   dependencies:
     assert "^2.0.0"
     bcrypto "^5.0.4"
     bn.js "^5.1.1"
     buffer "^5.4.3"
 
-"@chainsafe/bls-keygen@^0.2.0":
-  version "0.2.0"
-  resolved "https://registry.yarnpkg.com/@chainsafe/bls-keygen/-/bls-keygen-0.2.0.tgz#2089da875caff4334723c5ee45495e366dc57a2e"
-  integrity sha512-IcgOJ1UTiHX3T1FnSqTdf4gtavjpINPtmAwLZFQUxSuLPOfmxPPVN/yhAIYw5xCh9/mWkaFQ/dFUk6ys+BkfGQ==
+"@chainsafe/bls-keygen@^0.3.0":
+  version "0.3.0"
+  resolved "https://registry.yarnpkg.com/@chainsafe/bls-keygen/-/bls-keygen-0.3.0.tgz#d7472a945f6f49b5cb357241bfba2f5c12a635c5"
+  integrity sha512-5Iq6E5E987hyio74G1fXPYI3t9iVeHxRX1tDMpnCV9T82rPz061yFsMz3W3aXE26+k6+fcz0bsYX3ijOizkx+A==
   dependencies:
-    "@chainsafe/bls-hd-key" "^0.1.0"
-    assert "^2.0.0"
-    bcrypto "^5.0.4"
+    "@chainsafe/bls-hd-key" "^0.2.0"
     bip39 "^3.0.2"
     buffer "^5.4.3"
+    randombytes "^2.1.0"
 
 "@chainsafe/eth2-bls-wasm@^0.5.0":
   version "0.5.0"
@@ -1339,7 +1338,7 @@ asn1.js@^4.0.0:
     inherits "^2.0.1"
     minimalistic-assert "^1.0.0"
 
-assert@^1.1.1, assert@^1.4.1:
+assert@^1.1.1:
   version "1.5.0"
   resolved "https://registry.yarnpkg.com/assert/-/assert-1.5.0.tgz#55c109aaf6e0aefdb3dc4b71240c70bf574b18eb"
   integrity sha512-EDsgawzwoun2CZkCgtxJbv392v4nbk9XDD06zI+kQYoBM/3RBWLlEyJARDOmhAAosBjWACEkKL6S+lIZtcAubA==
@@ -4360,6 +4359,11 @@ nan@^2.12.1, nan@^2.14.0:
   resolved "https://registry.yarnpkg.com/nan/-/nan-2.14.0.tgz#7818f722027b2459a86f0295d434d1fc2336c52c"
   integrity sha512-INOFj37C7k3AfaNTtX8RhsTw7qRy7eLET14cROi9+5HAVbbHuIWUHEauBv5qT4Av2tWasiTY1Jw6puUNqRJXQg==
 
+nan@^2.14.1:
+  version "2.14.2"
+  resolved "https://registry.yarnpkg.com/nan/-/nan-2.14.2.tgz#f5376400695168f4cc694ac9393d0c9585eeea19"
+  integrity sha512-M2ufzIiINKCuDfBSAUr1vWQ+vuVcA9kqx8JJUsbQi6yf1uGRyb7HfpdfUr5qLXf3B/t8dPvcjhKMmlfnP47EzQ==
+
 nanomatch@^1.2.9:
   version "1.2.13"
   resolved "https://registry.yarnpkg.com/nanomatch/-/nanomatch-1.2.13.tgz#b87a8aa4fc0de8fe6be88895b38983ff265bd119"
@@ -5062,7 +5066,7 @@ querystring@0.2.0:
   resolved "https://registry.yarnpkg.com/querystring/-/querystring-0.2.0.tgz#b209849203bb25df820da756e747005878521620"
   integrity sha1-sgmEkgO7Jd+CDadW50cAWHhSFiA=
 
-randombytes@^2.0.0, randombytes@^2.0.1, randombytes@^2.0.5:
+randombytes@^2.0.0, randombytes@^2.0.1, randombytes@^2.0.5, randombytes@^2.1.0:
   version "2.1.0"
   resolved "https://registry.yarnpkg.com/randombytes/-/randombytes-2.1.0.tgz#df6f84372f0270dc65cdf6291349ab7a473d4f2a"
   integrity sha512-vYl3iOX+4CKUWuxGi9Ukhie6fsqXqS9FE2Zaic4tNFD2N2QQaXOMFbuKK4QmDHC0JO6B1Zp41J0LpT0oR68amQ==
@@ -6252,12 +6256,12 @@ v8-compile-cache@^2.0.3:
   resolved "https://registry.yarnpkg.com/v8-compile-cache/-/v8-compile-cache-2.1.0.tgz#e14de37b31a6d194f5690d67efc4e7f6fc6ab30e"
   integrity sha512-usZBT3PW+LOjM25wbqIlZwPeJV+3OSz3M1k1Ws8snlW39dZyYL9lOGC5FgPVHfk0jKmjiDV8Z0mIbVQPiwFs7g==
 
-v8-profiler-next@^1.1.1:
-  version "1.2.1"
-  resolved "https://registry.yarnpkg.com/v8-profiler-next/-/v8-profiler-next-1.2.1.tgz#4dad63273503f180cdec8bf80c458c61d78e49c7"
-  integrity sha512-5YyzfBycl5HA3dx7AnmRosxr7m77OzhCANGl7AkeciHFw03NThHSerCpPgD1bztRvnQhmYrp7sAnwdQm+WwCfQ==
+v8-profiler-next@1.3.0, v8-profiler-next@^1.1.1:
+  version "1.3.0"
+  resolved "https://registry.yarnpkg.com/v8-profiler-next/-/v8-profiler-next-1.3.0.tgz#7b8b01c353a5e4675eadcd720957f84a2882c84c"
+  integrity sha512-UrG750R9s43a3vInsLFHBnL8EbkSJ8d/yovYRKLk1myDeW2xdcQgcEKzVzlxLNDgULgDoLALn02VSw8BTH8M3w==
   dependencies:
-    nan "^2.14.0"
+    nan "^2.14.1"
 
 validate-npm-package-license@^3.0.1:
   version "3.0.4"