diff --git a/core/shared/src/main/scala/coursier/core/Repository.scala b/core/shared/src/main/scala/coursier/core/Repository.scala
index 955b35f7d..6afcfec04 100644
--- a/core/shared/src/main/scala/coursier/core/Repository.scala
+++ b/core/shared/src/main/scala/coursier/core/Repository.scala
@@ -1,8 +1,8 @@
 package coursier.core
 
 import coursier.Fetch
-
 import coursier.core.compatibility.encodeURIComponent
+import coursier.maven.MavenSource
 import coursier.util.{EitherT, Monad}
 
 trait Repository extends Product with Serializable {
@@ -24,19 +24,28 @@ object Repository {
         "SHA-1" -> (underlying.url + ".sha1"),
         "SHA-256" -> (underlying.url + ".sha256")
       ))
-    def withDefaultSignature: Artifact =
+    def withDefaultSignature: Artifact = {
+
+      val underlyingExt =
+        if (underlying.attributes.`type`.isEmpty)
+          "jar"
+        else
+          // TODO move MavenSource.typeExtension elsewhere
+          MavenSource.typeExtension(underlying.attributes.`type`)
+
       underlying.copy(extra = underlying.extra ++ Seq(
         "sig" ->
           Artifact(
             underlying.url + ".asc",
             Map.empty,
             Map.empty,
-            Attributes("asc", ""),
+            Attributes(s"$underlyingExt.asc", ""),
             changing = underlying.changing,
             authentication = underlying.authentication
           )
             .withDefaultChecksums
       ))
+    }
   }
 }
 
diff --git a/core/shared/src/main/scala/coursier/maven/MavenSource.scala b/core/shared/src/main/scala/coursier/maven/MavenSource.scala
index 2fcccfa10..1f6d9c53c 100644
--- a/core/shared/src/main/scala/coursier/maven/MavenSource.scala
+++ b/core/shared/src/main/scala/coursier/maven/MavenSource.scala
@@ -46,22 +46,17 @@ final case class MavenSource(
       )
 
       val changing0 = changing.getOrElse(isSnapshot(project.actualVersion))
-      var artifact =
-        Artifact(
-          root + path.mkString("/"),
-          Map.empty,
-          Map.empty,
-          publication.attributes,
-          changing = changing0,
-          authentication = authentication
-        )
-          .withDefaultChecksums
-          .withDefaultSignature
 
-      if (publication.ext == "jar")
-        artifact = artifact.withDefaultSignature
-
-      artifact
+      Artifact(
+        root + path.mkString("/"),
+        Map.empty,
+        Map.empty,
+        publication.attributes,
+        changing = changing0,
+        authentication = authentication
+      )
+        .withDefaultChecksums
+        .withDefaultSignature
     }
 
     val metadataArtifact = artifactOf(Publication(dependency.module.name, "pom", "pom", ""))