diff --git a/src/limit-order/limit-order.ts b/src/limit-order/limit-order.ts
index f5c4a55..0d6908b 100644
--- a/src/limit-order/limit-order.ts
+++ b/src/limit-order/limit-order.ts
@@ -12,8 +12,6 @@ import {MakerTraits} from './maker-traits'
 import {Extension} from './extension'
 import {Address} from '../address'
 
-const ZeroAddressHalf = '0'.repeat(20)
-
 export class LimitOrder {
     private static readonly Web3Type = `tuple(${[
         'uint256 salt',
@@ -142,7 +140,10 @@ export class LimitOrder {
         return getOrderHash(this.getTypedData(getLimitOrderV4Domain(chainId)))
     }
 
+    /**
+     * Returns true if only a specific address can fill order
+     */
     public isPrivate(): boolean {
-        return this.makerTraits.allowedSender() !== ZeroAddressHalf
+        return this.makerTraits.isPrivate()
     }
 }
diff --git a/src/limit-order/maker-traits.ts b/src/limit-order/maker-traits.ts
index 9a2451f..8fe2777 100644
--- a/src/limit-order/maker-traits.ts
+++ b/src/limit-order/maker-traits.ts
@@ -67,6 +67,10 @@ export class MakerTraits {
             .padStart(20, '0')
     }
 
+    public isPrivate(): boolean {
+        return this.value.getMask(MakerTraits.ALLOWED_SENDER_MASK).value !== 0n
+    }
+
     public withAllowedSender(sender: Address): this {
         assert(!sender.isZero(), 'Use withAnySender() to remove sender check')