diff --git a/src/cmd_rsa_decrypt.rs b/src/cmd_rsa_decrypt.rs
index 01d859a..fa8a0a4 100644
--- a/src/cmd_rsa_decrypt.rs
+++ b/src/cmd_rsa_decrypt.rs
@@ -38,8 +38,6 @@ impl Command for CommandImpl {
         let padding = crate::rsautil::parse_padding(padding_opt)?;
         let padding_str = crate::rsautil::padding_to_string(padding);
 
-        let mut json = BTreeMap::new();
-
         let keypair = opt_result!(Rsa::private_key_from_pem(&pri_key_bytes), "Parse RSA failed: {}");
         let keypair = opt_result!(PKey::from_rsa(keypair), "RSA to PKey failed: {}");
 
@@ -80,12 +78,11 @@ impl Command for CommandImpl {
         success!("Message HEX: {}", hex::encode(&data));
         success!("Message: {}", String::from_utf8_lossy(&data));
         if json_output {
+            let mut json = BTreeMap::new();
             json.insert("data", hex::encode(&data));
             json.insert("padding", padding_str.to_string());
             json.insert("encrypted", encrypted_hex);
-        }
 
-        if json_output {
             util::print_pretty_json(&json);
         }
 
diff --git a/src/cmd_rsa_encrypt.rs b/src/cmd_rsa_encrypt.rs
index 3156793..1143170 100644
--- a/src/cmd_rsa_encrypt.rs
+++ b/src/cmd_rsa_encrypt.rs
@@ -35,8 +35,6 @@ impl Command for CommandImpl {
         let padding = crate::rsautil::parse_padding(padding_opt)?;
         let padding_str = crate::rsautil::padding_to_string(padding);
 
-        let mut json = BTreeMap::new();
-
         let keypair = opt_result!(Rsa::public_key_from_pem(&pub_key_bytes), "Parse RSA failed: {}");
         let pub_key_der = opt_result!(keypair.public_key_to_der(), "RSA public key to der failed: {}");
         let pub_key_fingerprint = hex::encode(sha256_bytes(&pub_key_der));
@@ -64,13 +62,12 @@ impl Command for CommandImpl {
         information!("Public key fingerprint: {}", pub_key_fingerprint);
         success!("Encrypted message: {}", encrypted_hex);
         if json_output {
+            let mut json = BTreeMap::new();
             json.insert("data", hex::encode(&data));
             json.insert("public_key_fingerprint", pub_key_fingerprint);
             json.insert("padding", padding_str.to_string());
             json.insert("encrypted", encrypted_hex);
-        }
 
-        if json_output {
             util::print_pretty_json(&json);
         }
 
diff --git a/src/cmd_se.rs b/src/cmd_se.rs
index a2331d2..33c0903 100644
--- a/src/cmd_se.rs
+++ b/src/cmd_se.rs
@@ -19,9 +19,8 @@ impl Command for CommandImpl {
     fn run(&self, _arg_matches: &ArgMatches, sub_arg_matches: &ArgMatches) -> CommandError {
         let json_output = cmdutil::check_json_output(sub_arg_matches);
 
-        let mut json = BTreeMap::new();
-
         if json_output {
+            let mut json = BTreeMap::new();
             json.insert("se_supported", seutil::is_support_se());
 
             util::print_pretty_json(&json);
diff --git a/src/cmd_se_recover.rs b/src/cmd_se_recover.rs
index f87b34f..8f3dc08 100644
--- a/src/cmd_se_recover.rs
+++ b/src/cmd_se_recover.rs
@@ -27,9 +27,7 @@ impl Command for CommandImpl {
     fn run(&self, _arg_matches: &ArgMatches, sub_arg_matches: &ArgMatches) -> CommandError {
         let json_output = cmdutil::check_json_output(sub_arg_matches);
 
-        if !seutil::is_support_se() {
-            return simple_error!("Secure Enclave is NOT supported.");
-        }
+        seutil::check_se_supported()?;
         let key_uri = sub_arg_matches.value_of("key").unwrap();
 
         let KeyUri::SecureEnclaveKey(se_key_uri) = parse_key_uri(key_uri)?;
diff --git a/src/cmd_u2f_register.rs b/src/cmd_u2f_register.rs
index 5ca36c8..8d77a92 100644
--- a/src/cmd_u2f_register.rs
+++ b/src/cmd_u2f_register.rs
@@ -96,8 +96,8 @@ impl Command for CommandImpl {
             + u2f_registration_data.attestation_cert.as_ref().map(|c| c.len()).unwrap_or(0);
         let sign = &register_result.0[sign_prefix_len..];
 
-        let mut json = BTreeMap::new();
         if json_output {
+            let mut json = BTreeMap::new();
             // println!("{}", serde_json::to_string_pretty(&u2f_registration_data).unwrap());
             if let Some(device_name) = u2f_registration_data.device_name {
                 json.insert("device_name", device_name);
@@ -115,6 +115,8 @@ impl Command for CommandImpl {
             json.insert("app_id_hash", hex::encode(&app_id_hash));
             json.insert("challenge", u2fv2_challenge_str);
             json.insert("challenge_hash", hex::encode(&challenge_hash));
+
+            util::print_pretty_json(&json);
         } else {
             success!("Device info: {}", u2f_registration_data.device_info);
             information!("Register challenge: {}", u2fv2_challenge_str);
@@ -147,9 +149,6 @@ impl Command for CommandImpl {
                 warning!("Cannot find attestation cert!");
             }
         }
-        if json_output {
-            util::print_pretty_json(&json);
-        }
         Ok(None)
     }
 }