diff --git a/SecretAgent/Notifier.swift b/SecretAgent/Notifier.swift
index 19d93ea..b759f8a 100644
--- a/SecretAgent/Notifier.swift
+++ b/SecretAgent/Notifier.swift
@@ -1,5 +1,6 @@
 import Foundation
 import SecretKit
+import SecretAgentKit
 import UserNotifications
 
 class Notifier {
@@ -10,7 +11,7 @@ class Notifier {
         }
     }
 
-    func notify<SecretType: Secret>(accessTo secret: SecretType) {
+    func notify(accessTo secret: AnySecret) {
         let notificationCenter = UNUserNotificationCenter.current()
         let notificationContent = UNMutableNotificationContent()
         notificationContent.title = "Signed Request"
@@ -20,3 +21,11 @@ class Notifier {
     }
 
 }
+
+extension Notifier: SigningWitness {
+
+    func witness(accessTo secret: AnySecret) throws {
+        notify(accessTo: secret)
+    }
+
+}
diff --git a/SecretAgentKit/Agent.swift b/SecretAgentKit/Agent.swift
index 8e90c8e..73d6240 100644
--- a/SecretAgentKit/Agent.swift
+++ b/SecretAgentKit/Agent.swift
@@ -6,20 +6,20 @@ import SecretKit
 public class Agent {
 
     fileprivate let storeList: SecretStoreList
-//    fileprivate let notifier: Notifier
+    fileprivate let witness: SigningWitness?
     fileprivate let writer = OpenSSHKeyWriter()
 
-    public init(storeList: SecretStoreList/*, notifier: Notifier*/) {
+    public init(storeList: SecretStoreList, witness: SigningWitness? = nil) {
         os_log(.debug, "Agent is running")
         self.storeList = storeList
-//        self.notifier = notifier
+        self.witness = witness
     }
     
 }
 
 extension Agent {
 
-    public tfunc handle(fileHandle: FileHandle) {
+    public func handle(fileHandle: FileHandle) {
         os_log(.debug, "Agent handling new data")
         let data = fileHandle.availableData
         guard !data.isEmpty else { return }
@@ -78,12 +78,17 @@ extension Agent {
         let reader = OpenSSHReader(data: data)
         let hash = try reader.readNextChunk()
         guard let (store, secret) = secret(matching: hash) else {
+            os_log(.debug, "Agent did not have a key matching %@", hash as NSData)
             throw AgentError.noMatchingKey
         }
+
+        if let witness = witness {
+            try witness.witness(accessTo: secret)
+        }
+
         let dataToSign = try reader.readNextChunk()
         let derSignature = try store.sign(data: dataToSign, with: secret)
-        // TODO: Move this
-//        notifier.notify(accessTo: secret)
+
         let curveData = writer.curveType(for: secret.algorithm, length: secret.keySize).data(using: .utf8)!
 
         // Convert from DER formatted rep to raw (r||s)
diff --git a/SecretAgentKit/SigningWitness.swift b/SecretAgentKit/SigningWitness.swift
new file mode 100644
index 0000000..67577c3
--- /dev/null
+++ b/SecretAgentKit/SigningWitness.swift
@@ -0,0 +1,8 @@
+import Foundation
+import SecretKit
+
+public protocol SigningWitness {
+
+    func witness(accessTo secret: AnySecret) throws
+
+}
diff --git a/Secretive.xcodeproj/project.pbxproj b/Secretive.xcodeproj/project.pbxproj
index 447a66b..d6261ef 100644
--- a/Secretive.xcodeproj/project.pbxproj
+++ b/Secretive.xcodeproj/project.pbxproj
@@ -34,6 +34,7 @@
 		50731669241E00C20023809E /* NoticeView.swift in Sources */ = {isa = PBXBuildFile; fileRef = 50731668241E00C20023809E /* NoticeView.swift */; };
 		507CE4ED2420A3C70029F750 /* Agent.swift in Sources */ = {isa = PBXBuildFile; fileRef = 50A3B79F24026B9900D209EA /* Agent.swift */; };
 		507CE4EE2420A3CA0029F750 /* SocketController.swift in Sources */ = {isa = PBXBuildFile; fileRef = 50A3B79D24026B9900D209EA /* SocketController.swift */; };
+		507CE4F02420A4C50029F750 /* SigningWitness.swift in Sources */ = {isa = PBXBuildFile; fileRef = 507CE4EF2420A4C50029F750 /* SigningWitness.swift */; };
 		508A58AA241E06B40069DC07 /* PreviewUpdater.swift in Sources */ = {isa = PBXBuildFile; fileRef = 508A58A9241E06B40069DC07 /* PreviewUpdater.swift */; };
 		508A58B3241ED2180069DC07 /* AgentStatusChecker.swift in Sources */ = {isa = PBXBuildFile; fileRef = 508A58B2241ED2180069DC07 /* AgentStatusChecker.swift */; };
 		508A58B5241ED48F0069DC07 /* PreviewAgentStatusChecker.swift in Sources */ = {isa = PBXBuildFile; fileRef = 508A58B4241ED48F0069DC07 /* PreviewAgentStatusChecker.swift */; };
@@ -98,6 +99,13 @@
 			remoteGlobalIDString = 50617DA723FCE4AB0099B055;
 			remoteInfo = SecretKit;
 		};
+		507CE4F12420A6B50029F750 /* PBXContainerItemProxy */ = {
+			isa = PBXContainerItemProxy;
+			containerPortal = 50617D7723FCE48D0099B055 /* Project object */;
+			proxyType = 1;
+			remoteGlobalIDString = 50617DA723FCE4AB0099B055;
+			remoteInfo = SecretKit;
+		};
 		5099A076240242BA0062B6F2 /* PBXContainerItemProxy */ = {
 			isa = PBXContainerItemProxy;
 			containerPortal = 50617D7723FCE48D0099B055 /* Project object */;
@@ -194,6 +202,7 @@
 		506838A22415EA5D00F55094 /* AnySecretStore.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AnySecretStore.swift; sourceTree = "<group>"; };
 		50731665241DF8660023809E /* Updater.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Updater.swift; sourceTree = "<group>"; };
 		50731668241E00C20023809E /* NoticeView.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = NoticeView.swift; sourceTree = "<group>"; };
+		507CE4EF2420A4C50029F750 /* SigningWitness.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = SigningWitness.swift; sourceTree = "<group>"; };
 		508A58A9241E06B40069DC07 /* PreviewUpdater.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PreviewUpdater.swift; sourceTree = "<group>"; };
 		508A58AB241E121B0069DC07 /* Config.xcconfig */ = {isa = PBXFileReference; lastKnownFileType = text.xcconfig; path = Config.xcconfig; sourceTree = "<group>"; };
 		508A58B2241ED2180069DC07 /* AgentStatusChecker.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = AgentStatusChecker.swift; sourceTree = "<group>"; };
@@ -458,6 +467,7 @@
 				5099A06E240242BA0062B6F2 /* SecretAgentKit.h */,
 				5099A089240242C20062B6F2 /* SSHAgentProtocol.swift */,
 				50A3B79D24026B9900D209EA /* SocketController.swift */,
+				507CE4EF2420A4C50029F750 /* SigningWitness.swift */,
 				50A3B79F24026B9900D209EA /* Agent.swift */,
 				5099A06F240242BA0062B6F2 /* Info.plist */,
 			);
@@ -611,6 +621,7 @@
 			buildRules = (
 			);
 			dependencies = (
+				507CE4F22420A6B50029F750 /* PBXTargetDependency */,
 			);
 			name = SecretAgentKit;
 			productName = SecretAgentKit;
@@ -838,6 +849,7 @@
 				507CE4EE2420A3CA0029F750 /* SocketController.swift in Sources */,
 				5099A08A240242C20062B6F2 /* SSHAgentProtocol.swift in Sources */,
 				507CE4ED2420A3C70029F750 /* Agent.swift in Sources */,
+				507CE4F02420A4C50029F750 /* SigningWitness.swift in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};
@@ -886,6 +898,11 @@
 			target = 50617DA723FCE4AB0099B055 /* SecretKit */;
 			targetProxy = 50617DBB23FCE4AB0099B055 /* PBXContainerItemProxy */;
 		};
+		507CE4F22420A6B50029F750 /* PBXTargetDependency */ = {
+			isa = PBXTargetDependency;
+			target = 50617DA723FCE4AB0099B055 /* SecretKit */;
+			targetProxy = 507CE4F12420A6B50029F750 /* PBXContainerItemProxy */;
+		};
 		5099A077240242BA0062B6F2 /* PBXTargetDependency */ = {
 			isa = PBXTargetDependency;
 			target = 5099A06B240242BA0062B6F2 /* SecretAgentKit */;