diff --git a/packages/sdk-viem/src/utils/helpers.ts b/packages/sdk-viem/src/utils/helpers.ts
index 240b2492..30c855cb 100644
--- a/packages/sdk-viem/src/utils/helpers.ts
+++ b/packages/sdk-viem/src/utils/helpers.ts
@@ -1,8 +1,9 @@
-import keccak256 from 'keccak256'
 import { isHex, type Hex } from 'viem'
+import { InvalidHexError } from '../errors'
+import keccak256 from 'keccak256'
 
-export function isHexList(list: string[]): list is Hex[] {
-  return list.every((value) => isHex(value))
+export function assertIsHex(value: string): asserts value is Hex {
+  if (!isHex(value, { strict: false })) throw new InvalidHexError({ value })
 }
 
 export function getSaltAsBytes32(salt: string | number) {
@@ -67,6 +68,16 @@ export async function retry<T>(
   return fn()
 }
 
+export function isHexList(list: string[]): list is Hex[] {
+  return list.every((value) => isHex(value, { strict: false }))
+}
+
+export function assertIsHexList(list: string[]): asserts list is Hex[] {
+  for (const value of list) {
+    assertIsHex(value)
+  }
+}
+
 type NonEmptyArray<T> = [T, ...T[]]
 
 export function BigIntMin(...[firstValue, ...values]: NonEmptyArray<bigint>): bigint {