diff --git a/src/libcmd/include/nix/cmd/command.hh b/src/libcmd/include/nix/cmd/command.hh
index 20cd1abc1..2bff11dc1 100644
--- a/src/libcmd/include/nix/cmd/command.hh
+++ b/src/libcmd/include/nix/cmd/command.hh
@@ -350,6 +350,20 @@ struct MixEnvironment : virtual Args
     void setEnviron();
 };
 
+struct MixNoCheckSigs : virtual Args
+{
+    CheckSigsFlag checkSigs = CheckSigs;
+
+    MixNoCheckSigs()
+    {
+        addFlag({
+            .longName = "no-check-sigs",
+            .description = "Do not require that paths are signed by trusted keys.",
+            .handler = {&checkSigs, NoCheckSigs},
+        });
+    }
+};
+
 void completeFlakeInputAttrPath(
     AddCompletions & completions,
     ref<EvalState> evalState,
diff --git a/src/nix/copy.cc b/src/nix/copy.cc
index 62e8b64f5..706edc6c9 100644
--- a/src/nix/copy.cc
+++ b/src/nix/copy.cc
@@ -5,10 +5,9 @@
 
 using namespace nix;
 
-struct CmdCopy : virtual CopyCommand, virtual BuiltPathsCommand, MixProfile
+struct CmdCopy : virtual CopyCommand, virtual BuiltPathsCommand, MixProfile, MixNoCheckSigs
 {
     std::optional<std::filesystem::path> outLink;
-    CheckSigsFlag checkSigs = CheckSigs;
 
     SubstituteFlag substitute = NoSubstitute;
 
@@ -24,13 +23,6 @@ struct CmdCopy : virtual CopyCommand, virtual BuiltPathsCommand, MixProfile
             .handler = {&outLink},
             .completer = completePath,
         });
-
-        addFlag({
-            .longName = "no-check-sigs",
-            .description = "Do not require that paths are signed by trusted keys.",
-            .handler = {&checkSigs, NoCheckSigs},
-        });
-
         addFlag({
             .longName = "substitute-on-destination",
             .shortName = 's',
diff --git a/src/nix/flake.cc b/src/nix/flake.cc
index cf05f6943..04d4ec8eb 100644
--- a/src/nix/flake.cc
+++ b/src/nix/flake.cc
@@ -1032,12 +1032,10 @@ struct CmdFlakeClone : FlakeCommand
     }
 };
 
-struct CmdFlakeArchive : FlakeCommand, MixJSON, MixDryRun
+struct CmdFlakeArchive : FlakeCommand, MixJSON, MixDryRun, MixNoCheckSigs
 {
     std::string dstUri;
 
-    CheckSigsFlag checkSigs = CheckSigs;
-
     SubstituteFlag substitute = NoSubstitute;
 
     CmdFlakeArchive()
@@ -1048,11 +1046,6 @@ struct CmdFlakeArchive : FlakeCommand, MixJSON, MixDryRun
             .labels = {"store-uri"},
             .handler = {&dstUri},
         });
-        addFlag({
-            .longName = "no-check-sigs",
-            .description = "Do not require that paths are signed by trusted keys.",
-            .handler = {&checkSigs, NoCheckSigs},
-        });
     }
 
     std::string description() override
diff --git a/src/nix/sigs.cc b/src/nix/sigs.cc
index 470cd3951..142421e9c 100644
--- a/src/nix/sigs.cc
+++ b/src/nix/sigs.cc
@@ -104,6 +104,7 @@ struct CmdSign : StorePathsCommand
             .labels = {"file"},
             .handler = {&secretKeyFile},
             .completer = completePath,
+            .required = true,
         });
     }
 
@@ -114,9 +115,6 @@ struct CmdSign : StorePathsCommand
 
     void run(ref<Store> store, StorePaths && storePaths) override
     {
-        if (secretKeyFile.empty())
-            throw UsageError("you must specify a secret key file using '-k'");
-
         SecretKey secretKey(readFile(secretKeyFile));
         LocalSigner signer(std::move(secretKey));