diff --git a/src/util/module.zig b/src/util/module.zig
index 788d4ca6db8f4a1e4d618e0f52232273ca579155..4ada8eb30780538c4c37f5f871c89c63b6442f4f 100644
--- a/src/util/module.zig
+++ b/src/util/module.zig
@@ -71,7 +71,7 @@ pub const Module = struct {
         }
         var out: [32]u8 = undefined;
         h.final(&out);
-        const hex = try std.fmt.allocPrint(gpa, "{x}", .{out});
+        const hex = try std.fmt.allocPrint(gpa, "blake3-{x}", .{out});
         return hex;
     }