Describe unavailable key types

Sources/Packages/Resources/Localizable.xcstrings

@@ -17031,6 +17031,9 @@
           }
         }
       }
+    },
+    "macOS Tahoe or Later Required" : {
+
     },
     "no_secure_storage_description" : {
       "extractionState" : "manual",

Sources/Packages/Sources/SecretKit/Erasers/AnySecretStore.swift

@@ -64,7 +64,7 @@ public final class AnySecretStoreModifiable: AnySecretStore, SecretStoreModifiab
     private let _create: @Sendable (String, Attributes) async throws -> AnySecret
     private let _delete: @Sendable (AnySecret) async throws -> Void
     private let _update: @Sendable (AnySecret, String, Attributes) async throws -> Void
-    private let _supportedKeyTypes: @Sendable () -> [KeyType]
+    private let _supportedKeyTypes: @Sendable () -> KeyAvailability
 
     public init<SecretStoreType>(_ secretStore: SecretStoreType) where SecretStoreType: SecretStoreModifiable {
         _create = { AnySecret(try await secretStore.create(name: $0, attributes: $1)) }
@@ -87,7 +87,7 @@ public final class AnySecretStoreModifiable: AnySecretStore, SecretStoreModifiab
         try await _update(secret, name, attributes)
     }
 
-    public var supportedKeyTypes: [KeyType] {
+    public var supportedKeyTypes: KeyAvailability {
         _supportedKeyTypes()
     }
 

Sources/Packages/Sources/SecretKit/Types/SecretStore.swift

@@ -62,10 +62,33 @@ public protocol SecretStoreModifiable<SecretType>: SecretStore {
     ///   - attributes: The new attributes for the secret.
     func update(secret: SecretType, name: String, attributes: Attributes) async throws
 
-    var supportedKeyTypes: [KeyType] { get }
+    var supportedKeyTypes: KeyAvailability { get }
 
 }
 
+public struct KeyAvailability: Sendable {
+
+    public let available: [KeyType]
+    public let unavailable: [UnavailableKeyType]
+
+    public init(available: [KeyType], unavailable: [UnavailableKeyType]) {
+        self.available = available
+        self.unavailable = unavailable
+    }
+
+    public struct UnavailableKeyType: Sendable {
+        public let keyType: KeyType
+        public let reason: LocalizedStringResource
+
+        public init(keyType: KeyType, reason: LocalizedStringResource) {
+            self.keyType = keyType
+            self.reason = reason
+        }
+    }
+
+}
+
+
 extension NSNotification.Name {
 
     // Distributed notification that keys were modified out of process (ie, that the management tool added/removed secrets)

Sources/Packages/Sources/SecureEnclaveSecretKit/SecureEnclaveStore.swift

@@ -186,17 +186,22 @@ extension SecureEnclave {
             await reloadSecrets()
         }
         
-        public var supportedKeyTypes: [KeyType] {
+        public let supportedKeyTypes: KeyAvailability = {
-            if #available(macOS 26, *) {
+            let macOS26Keys: [KeyType] = [.mldsa65, .mldsa87]
-                [
+            let isAtLeastMacOS26 = if #available(macOS 26, *) {
-                    .ecdsa256,
+                true
-                    .mldsa65,
-                    .mldsa87,
-                ]
             } else {
-                [.ecdsa256]
+                false
             }
-        }
+            return KeyAvailability(
+                available: [
+                    .ecdsa256,
+                ] + (isAtLeastMacOS26 ? macOS26Keys : []),
+                unavailable: (isAtLeastMacOS26 ? [] : macOS26Keys).map {
+                    KeyAvailability.UnavailableKeyType(keyType: $0, reason: "macOS Tahoe or Later Required")
+                }
+            )
+        }()
     }
 
 }

Sources/Secretive/Preview Content/PreviewStore.swift

@@ -60,16 +60,21 @@ extension Preview {
         let id = UUID()
         var name: String { "Modifiable Preview Store" }
         let secrets: [Secret]
-        var supportedKeyTypes: [KeyType] {
+        var supportedKeyTypes: KeyAvailability {
-            if #available(macOS 26, *) {
+            let macOS26Keys: [KeyType] = [.mldsa65, .mldsa87]
-                [
+            let isAtLeastMacOS26 = if #available(macOS 26, *) {
-                    .ecdsa256,
+                true
-                    .mldsa65,
-                    .mldsa87,
-                ]
             } else {
-                [.ecdsa256]
+                false
             }
+            return KeyAvailability(
+                available: [
+                    .ecdsa256,
+                ] + (isAtLeastMacOS26 ? macOS26Keys : []),
+                unavailable: (isAtLeastMacOS26 ? [] : macOS26Keys).map {
+                    KeyAvailability.UnavailableKeyType(keyType: $0, reason: "macOS Tahoe or Later Required")
+                }
+            )
         }
         
         init(secrets: [Secret]) {

Sources/Secretive/Views/Secrets/CreateSecretView.swift

@@ -75,11 +75,21 @@ struct CreateSecretView<StoreType: SecretStoreModifiable>: View {
                     Section {
                         VStack {
                             Picker(.createSecretKeyTypeLabel, selection: $keyType) {
-                                ForEach(store.supportedKeyTypes, id: \.self) { option in
+                                ForEach(store.supportedKeyTypes.available, id: \.self) { option in
                                     Text(String(describing: option))
                                         .tag(option)
                                         .font(.caption)
                                 }
+                                Divider()
+                                ForEach(store.supportedKeyTypes.unavailable, id: \.keyType) { option in
+                                    VStack {
+                                        Text(String(describing: option.keyType))
+                                            .font(.caption)
+                                        Text(option.reason)
+                                            .font(.caption)
+                                    }
+                                    .disabled(true)
+                                }
                             }
                             if keyType?.algorithm == .mldsa {
                                 Text(.createSecretMldsaWarning)
@@ -119,7 +129,7 @@ struct CreateSecretView<StoreType: SecretStoreModifiable>: View {
             .padding()
         }
         .onAppear {
-            keyType = store.supportedKeyTypes.first
+            keyType = store.supportedKeyTypes.available.first
         }
         .formStyle(.grouped)
     }
@@ -146,6 +156,6 @@ struct CreateSecretView<StoreType: SecretStoreModifiable>: View {
 
 }
 
-//#Preview {
+#Preview {
-//    CreateSecretView(store: Preview.StoreModifiable()) { _ in }
+    CreateSecretView(store: Preview.StoreModifiable()) { _ in }
-//}
+}