diff --git a/Cargo.lock b/Cargo.lock
index 91199e2..46b6d5c 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -825,6 +825,7 @@ dependencies = [
 name = "ctss"
 version = "0.1.0"
 dependencies = [
+ "hex",
  "tss-lib",
 ]
 
diff --git a/ctss/Cargo.toml b/ctss/Cargo.toml
index 696984b..1511896 100644
--- a/ctss/Cargo.toml
+++ b/ctss/Cargo.toml
@@ -4,6 +4,7 @@ version = "0.1.0"
 edition = "2021"
 
 [dependencies]
+hex = "0.4.3"
 tss-lib = { path = "../tss" }
 
 [lib]
diff --git a/ctss/src/lib.rs b/ctss/src/lib.rs
index ac25977..c449450 100644
--- a/ctss/src/lib.rs
+++ b/ctss/src/lib.rs
@@ -1,9 +1,8 @@
-
-use std::os::raw::c_char;
 use std::ffi::CStr;
 use std::ffi::CString;
+use std::os::raw::c_char;
 
-use tss_lib::keygen;
+use tss_lib::{keygen, sign};
 
 pub fn parse_string(s: *const c_char) -> &'static str {
     let s = unsafe {
@@ -27,8 +26,42 @@ pub extern "C" fn keygen(
         index,
         threshold,
         number_of_parties,
-    ).unwrap();
+    )
+    .unwrap();
 
     let data = CString::new(data).unwrap();
     data.into_raw()
 }
+
+#[no_mangle]
+pub extern "C" fn sign(
+    server_url: *const c_char,
+    room: *const c_char,
+    local_share: *const c_char,
+    parties: *const c_char,
+    data: *const c_char,
+) -> *const c_char {
+    let parties = parse_string(parties)
+        .split(",")
+        .map(|c| c.trim().parse::<u16>().unwrap())
+        .collect();
+
+    let signature = sign::run(
+        parse_string(server_url),
+        parse_string(room),
+        parse_string(local_share),
+        parties,
+        parse_string(data).as_bytes(),
+    )
+    .unwrap();
+
+    let signature = format!(
+        r#"{{ "r":"0x{}", "s":"0x{}", "v":"{}" }}"#,
+        hex::encode(signature.r.to_bytes().as_ref()),
+        hex::encode(signature.s.to_bytes().as_ref()),
+        signature.recid,
+    );
+
+    let signature = CString::new(signature).unwrap();
+    signature.into_raw()
+}
diff --git a/examples/README.md b/examples/README.md
index cbe216c..fc5d984 100644
--- a/examples/README.md
+++ b/examples/README.md
@@ -5,4 +5,5 @@ ctss bind examples
 
 ```
 go build -ldflags="-r lib" keygen.go
+go build -ldflags="-r lib" sign.go
 ```
diff --git a/examples/golang/.gitignore b/examples/golang/.gitignore
index f75d948..7c43b85 100644
--- a/examples/golang/.gitignore
+++ b/examples/golang/.gitignore
@@ -1,2 +1,3 @@
 /keygen
+/sign
 /local-share*.json
diff --git a/examples/golang/lib/ctss.h b/examples/golang/lib/ctss.h
index fdddbc5..dc16d24 100644
--- a/examples/golang/lib/ctss.h
+++ b/examples/golang/lib/ctss.h
@@ -5,3 +5,9 @@ const char *keygen(const char *server_url,
                    uint16_t index,
                    uint16_t threshold,
                    uint16_t number_of_parties);
+
+const char *sign(const char *server_url,
+                 const char *room,
+                 const char *local_share,
+                 const char *parties,
+                 const char *data);
diff --git a/examples/golang/lib/libctss.dylib b/examples/golang/lib/libctss.dylib
index 0b9d88f..94c1541 100755
Binary files a/examples/golang/lib/libctss.dylib and b/examples/golang/lib/libctss.dylib differ
diff --git a/examples/golang/sign.go b/examples/golang/sign.go
new file mode 100644
index 0000000..4e8e7f0
--- /dev/null
+++ b/examples/golang/sign.go
@@ -0,0 +1,35 @@
+package main
+
+/*
+#cgo LDFLAGS: -L./lib -lctss
+#include "./lib/ctss.h"
+*/
+import "C"
+import (
+	"fmt"
+	"log"
+	"strconv"
+)
+
+func main() {
+	fmt.Println("input index:")
+	var indexStr string
+	_, err := fmt.Scanln(&indexStr)
+	if err != nil {
+		log.Fatalln(err)
+	}
+
+	index, err := strconv.Atoi(indexStr)
+	if err != nil {
+		log.Fatalln(err)
+	}
+	signature := C.sign(
+		C.CString("http://localhost:8000/"),
+		C.CString("default-keygen"),
+		C.CString(fmt.Sprintf("local-share%d.json", index)),
+		C.CString("1,2"),
+		C.CString("hello"),
+	)
+
+	fmt.Println(C.GoString(signature))
+}