diff --git a/.gitignore b/.gitignore
index ea8c4bf..48ee9ee 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,2 @@
 /target
+checksum.json
diff --git a/Cargo.lock b/Cargo.lock
index d26e51f..d07c24e 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2,6 +2,15 @@
 # It is not intended for manual editing.
 version = 4
 
+[[package]]
+name = "aho-corasick"
+version = "1.1.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ddd31a130427c27518df266943a5308ed92d4b226cc639f5a8f1002816174301"
+dependencies = [
+ "memchr",
+]
+
 [[package]]
 name = "crossbeam-deque"
 version = "0.8.6"
@@ -38,7 +47,9 @@ name = "hash-gen"
 version = "0.1.0"
 dependencies = [
  "memmap2",
+ "once_cell",
  "rayon",
+ "regex",
  "serde",
  "serde_json",
  "walkdir",
@@ -72,6 +83,12 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "once_cell"
+version = "1.21.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "42f5e15c9953c5e4ccceeb2e7382a716482c34515315f7b03532b8b4e8393d2d"
+
 [[package]]
 name = "proc-macro2"
 version = "1.0.103"
@@ -110,6 +127,35 @@ dependencies = [
  "crossbeam-utils",
 ]
 
+[[package]]
+name = "regex"
+version = "1.12.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "843bc0191f75f3e22651ae5f1e72939ab2f72a4bc30fa80a066bd66edefc24d4"
+dependencies = [
+ "aho-corasick",
+ "memchr",
+ "regex-automata",
+ "regex-syntax",
+]
+
+[[package]]
+name = "regex-automata"
+version = "0.4.13"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5276caf25ac86c8d810222b3dbb938e512c55c6831a10f3e6ed1c93b84041f1c"
+dependencies = [
+ "aho-corasick",
+ "memchr",
+ "regex-syntax",
+]
+
+[[package]]
+name = "regex-syntax"
+version = "0.8.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7a2d987857b319362043e95f5353c0535c1f58eec5336fdfcf626430af7def58"
+
 [[package]]
 name = "ryu"
 version = "1.0.20"
diff --git a/Cargo.toml b/Cargo.toml
index 1f26d03..32abd20 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -10,3 +10,5 @@ xxhash-rust = { version = "0.8.15", features = ["xxh3"] }
 rayon = "1.10"
 memmap2 = "0.9"
 walkdir = "2.3"
+regex = "1.12.2"
+once_cell = "*"
diff --git a/src/main.rs b/src/main.rs
index 6b10a06..68f1a30 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,23 +1,29 @@
 use memmap2::Mmap;
+use once_cell::sync::Lazy;
 use rayon::prelude::*;
+use regex::Regex;
 use serde_json::json;
 use std::{
     collections::BTreeMap,
     env, fs,
     fs::File,
     path::{Path, PathBuf},
-    sync::Mutex,
 };
 use walkdir::WalkDir;
 use xxhash_rust::xxh3::xxh3_64;
 
-fn hash_file(path: &Path) -> (String, String) {
+static RE: Lazy<Regex> = Lazy::new(|| {
+    Regex::new(r"(metin2\.exe|granny2\.dll|SpeedTreeRT\.dll|BGM[/\\].*|lib[/\\].*|pack[/\\].*)")
+        .unwrap()
+});
+
+fn hash_file(path: &Path, base_path: &String) -> (String, String) {
     let file = File::open(path).expect("Failed to open file");
     let mmap = unsafe { Mmap::map(&file).expect("Failed to mmap file") };
     let hash = xxh3_64(&mmap);
     let hash_str = hash.to_string();
 
-    let filename = path.file_name().unwrap().to_string_lossy().to_string();
+    let filename = path.to_str().unwrap().to_string().replace(base_path, "");
     (filename, hash_str)
 }
 
@@ -25,12 +31,15 @@ fn collect_files(folder: &Path) -> Vec<PathBuf> {
     WalkDir::new(folder)
         .into_iter()
         .filter_map(|e| e.ok())
-        .filter(|e| e.path().is_file())
+        .filter(|e| e.path().is_file() && RE.is_match(e.path().to_str().unwrap()))
         .map(|e| e.path().to_path_buf())
         .collect()
 }
 
 fn main() -> std::io::Result<()> {
+    use std::time::Instant;
+    let now = Instant::now();
+
     let args: Vec<String> = env::args().collect();
     if args.len() != 2 {
         eprintln!("Usage: {} <folder>", args[0]);
@@ -45,11 +54,13 @@ fn main() -> std::io::Result<()> {
 
     let files = collect_files(folder);
 
-    let results: BTreeMap<String, String> = files.par_iter().map(|f| hash_file(f)).collect();
+    let results: BTreeMap<String, String> =
+        files.par_iter().map(|f| hash_file(f, &args[1])).collect();
 
     let json_output = json!({ "checksums": results });
 
-    fs::write("checksum", serde_json::to_string_pretty(&json_output)?)?;
-    println!("Done! JSON saved to 'checksum'");
+    fs::write("checksum.json", serde_json::to_string_pretty(&json_output)?)?;
+    let elapsed = now.elapsed();
+    println!("Generated 'checksum', elapsed {:.2?}", elapsed);
     Ok(())
 }