diff --git a/src/main.rs b/src/main.rs
index a175ce2..de1088b 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -7,6 +7,7 @@ mod digest;
 mod register;
 mod sign;
 mod pgp;
+mod pgpcardutil;
 mod pgpcardlist;
 mod pgpcardsign;
 
diff --git a/src/pgpcardsign.rs b/src/pgpcardsign.rs
index 1a53e72..2c8721e 100644
--- a/src/pgpcardsign.rs
+++ b/src/pgpcardsign.rs
@@ -1,6 +1,6 @@
 use clap::{ArgMatches, SubCommand, App, Arg};
 use crate::cmd::{Command, CommandError};
-use openpgp_card::{OpenPGPCard, Hash, OpenPGPCardUser};
+use openpgp_card::Hash;
 use rust_util::XResult;
 use std::collections::BTreeMap;
 
@@ -38,7 +38,7 @@ impl Command for CommandImpl {
 
         let mut json = BTreeMap::new();
         if let Some(sha256) = sha256 {
-            let user = get_card_user_sw1_81(pass)?;
+            let user = crate::pgpcardutil::get_card_user_sw1_81(pass)?;
             let sha256_hex = opt_result!(hex::decode(sha256), "Decode sha256 failed: {}");
             let sha256_hex = copy_sha256(&sha256_hex)?;
             let sig = user.signature_for_hash(Hash::SHA256(sha256_hex))?;
@@ -52,7 +52,7 @@ impl Command for CommandImpl {
             }
         }
         if let Some(sha384) = sha384 {
-            let user = get_card_user_sw1_81(pass)?;
+            let user = crate::pgpcardutil::get_card_user_sw1_81(pass)?;
             let sha384_hex = opt_result!(hex::decode(sha384), "Decode sha384 failed: {}");
             let sha384_hex = copy_sha384(&sha384_hex)?;
             let sig = user.signature_for_hash(Hash::SHA384(sha384_hex))?;
@@ -66,7 +66,7 @@ impl Command for CommandImpl {
             }
         }
         if let Some(sha512) = sha512 {
-            let user = get_card_user_sw1_81(pass)?;
+            let user = crate::pgpcardutil::get_card_user_sw1_81(pass)?;
             let sha512_hex = opt_result!(hex::decode(sha512), "Decode sha512 failed: {}");
             let sha512_hex = copy_sha512(&sha512_hex)?;
             let sig = user.signature_for_hash(Hash::SHA512(sha512_hex))?;
@@ -106,20 +106,3 @@ macro_rules! define_copy_array {
 define_copy_array!(copy_sha256, 0x20);
 define_copy_array!(copy_sha384, 0x30);
 define_copy_array!(copy_sha512, 0x40);
-
-fn get_card_user_sw1_81(pass: &str) -> XResult<OpenPGPCardUser> {
-    match OpenPGPCard::list_cards() {
-        Ok(list) => {
-            // pw1_81 for signature
-            // openssl dgst -sha256 -verify aa -signature sig LICENSE
-            if list.is_empty() {
-                return simple_error!("Cannot find any card");
-            }
-            match list.into_iter().next().unwrap().verify_pw1_81(pass) {
-                Result::Ok(user) => Ok(user),
-                Result::Err(_) => simple_error!("Verify pw1_81 OpenPGP card failed"),
-            }
-        }
-        Err(e) => simple_error!("Read OpenPGP card failed: {}", e),
-    }
-}
diff --git a/src/pgpcardutil.rs b/src/pgpcardutil.rs
new file mode 100644
index 0000000..12cc831
--- /dev/null
+++ b/src/pgpcardutil.rs
@@ -0,0 +1,20 @@
+use rust_util::XResult;
+use openpgp_card::{OpenPGPCardUser, OpenPGPCard};
+
+pub fn get_card_user_sw1_81(pass: &str) -> XResult<OpenPGPCardUser> {
+    match OpenPGPCard::list_cards() {
+        Ok(list) => {
+            // pw1_81 for signature
+            // openssl dgst -sha256 -verify aa -signature sig LICENSE
+            if list.is_empty() {
+                return simple_error!("Cannot find any card");
+            }
+            match list.into_iter().next().unwrap().verify_pw1_81(pass) {
+                Result::Ok(user) => Ok(user),
+                Result::Err(_) => simple_error!("Verify pw1_81 OpenPGP card failed"),
+            }
+        }
+        Err(e) => simple_error!("Read OpenPGP card failed: {}", e),
+    }
+}
+