diff --git a/src/errors.ts b/src/errors.ts
index 8666707..62b2daa 100644
--- a/src/errors.ts
+++ b/src/errors.ts
@@ -3,3 +3,15 @@
  * by the functional interface try / catch blocks
  */
 export class ExpectedError extends Error {}
+
+export class ZeroPrivateKeyError extends Error {
+  constructor() {
+    super("PRIVATE_KEY_IS_ZERO");
+  }
+}
+
+export class ZeroPublicKeyError extends Error {
+  constructor() {
+    super("PUBLIC_KEY_IS_ZERO");
+  }
+}
diff --git a/src/herumi/privateKey.ts b/src/herumi/privateKey.ts
index 6fcfb7f..cfa5438 100644
--- a/src/herumi/privateKey.ts
+++ b/src/herumi/privateKey.ts
@@ -6,11 +6,16 @@ import {PublicKey} from "./publicKey";
 import {Signature} from "./signature";
 import {bytesToHex, hexToBytes} from "../helpers";
 import {IPrivateKey} from "../interface";
+import {ZeroPrivateKeyError} from "../errors";
 
 export class PrivateKey implements IPrivateKey {
   readonly value: SecretKeyType;
 
   constructor(value: SecretKeyType) {
+    if (value.isZero()) {
+      throw new ZeroPrivateKeyError();
+    }
+
     this.value = value;
   }
 
diff --git a/src/herumi/publicKey.ts b/src/herumi/publicKey.ts
index 441193e..fa15485 100644
--- a/src/herumi/publicKey.ts
+++ b/src/herumi/publicKey.ts
@@ -3,11 +3,16 @@ import {getContext} from "./context";
 import {EMPTY_PUBLIC_KEY, PUBLIC_KEY_LENGTH} from "../constants";
 import {bytesToHex, hexToBytes, isEqualBytes} from "../helpers";
 import {IPublicKey} from "../interface";
+import {ZeroPublicKeyError} from "../errors";
 
 export class PublicKey implements IPublicKey {
   readonly value: PublicKeyType;
 
   constructor(value: PublicKeyType) {
+    if (value.isZero()) {
+      throw new ZeroPublicKeyError();
+    }
+
     this.value = value;
   }
 
diff --git a/test/spec/sign.test.ts b/test/spec/sign.test.ts
index a90f21b..f8a9869 100644
--- a/test/spec/sign.test.ts
+++ b/test/spec/sign.test.ts
@@ -3,6 +3,7 @@ import {describeDirectorySpecTest, InputType} from "@chainsafe/lodestar-spec-tes
 import {bytesToHex, hexToBytes} from "../../src/helpers";
 import {SPEC_TESTS_DIR} from "../params";
 import {describeForAllImplementations} from "../switch";
+import {ZeroPrivateKeyError} from "../../src/errors";
 
 interface ISignMessageTestCase {
   data: {
@@ -19,9 +20,14 @@ describeForAllImplementations((bls) => {
     "bls/sign/small",
     path.join(SPEC_TESTS_DIR, "general/phase0/bls/sign/small"),
     (testCase) => {
-      const {privkey, message} = testCase.data.input;
-      const signature = bls.sign(hexToBytes(privkey), hexToBytes(message));
-      return bytesToHex(signature);
+      try {
+        const {privkey, message} = testCase.data.input;
+        const signature = bls.sign(hexToBytes(privkey), hexToBytes(message));
+        return bytesToHex(signature);
+      } catch (e) {
+        if (e instanceof ZeroPrivateKeyError) return null;
+        else throw e;
+      }
     },
     {
       inputTypes: {data: InputType.YAML},