# setCodeSigningRequirement(_:) Sets the code signing requirement for this connection. ``` func setCodeSigningRequirement(_ requirement: String) ``` ## Parameters `requirement` A string that describes requirements expected of the connection peer. See [Code Signing Guide](https://developer.apple.com/library/archive/documentation/Security/Conceptual/CodeSigningGuide/) for more information on the code signing format. ## Discussion Use this method to enforce a code-signing requirement on the peer process of an XPC connection. The following example shows how a client can ensure that the XPC service on the other end of a connection has a specific entitlement. ```objc NSXPCConnection *c = [[NSXPCConnection alloc] initWithServiceName:@"com.example.ExampleService"]; c.remoteObjectInterface = getServerInterface(); [c setCodeSigningRequirement:@"entitlement [com.example.testentitlement] exists"]; [c resume]; [[c remoteObjectProxyWithErrorHandler:^(NSError *error) { // If there is a code signing error, this block receives NSXPCConnectionCodeSigningRequirementFailure here. }] myMessageWithReply:^(BOOL arg) { // Handle success case here. }]; ``` Calling this method with a malformed `requirement` results in a fatal error in Swift, or throws an exception in Objective-C. If new messages don’t match the requirement, the connection becomes invalidated. Call this method before calling [`resume()`](/documentation/Foundation/NSXPCConnection/resume()), since it’s an XPC error to call this method more than once. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)