diff --git a/archive/src/main/kotlin/org/openrs2/archive/key/JsonKeyReader.kt b/archive/src/main/kotlin/org/openrs2/archive/key/JsonKeyReader.kt
index ffa8de3d..eea14fc8 100644
--- a/archive/src/main/kotlin/org/openrs2/archive/key/JsonKeyReader.kt
+++ b/archive/src/main/kotlin/org/openrs2/archive/key/JsonKeyReader.kt
@@ -14,7 +14,7 @@ public class JsonKeyReader @Inject constructor(
     @Json private val mapper: ObjectMapper
 ) : KeyReader {
     override fun read(input: InputStream): Sequence<XteaKey> {
-        val keys = mutableListOf<XteaKey>()
+        val keys = mutableSetOf<XteaKey>()
         val root = mapper.readTree(input)
 
         when {