diff --git a/src/x509.rs b/src/x509.rs
index 0c8f03c..fe4b2da 100644
--- a/src/x509.rs
+++ b/src/x509.rs
@@ -2,6 +2,12 @@ use x509_parser::parse_x509_certificate;
 use x509_parser::pem::parse_x509_pem;
 use x509_parser::extensions::ParsedExtension;
 use x509_parser::der_parser::oid::Oid;
+use std::str::FromStr;
+
+lazy_static! {
+    static ref OID_COMMON_NAME: Oid<'static> = Oid::from_str("2.5.4.3").unwrap();
+    static ref OID_RSA_WITH_SHA256: Oid<'static> = Oid::from_str("1.2.840.113549.1.1.11").unwrap();
+}
 
 #[test]
 fn test_x509() {
@@ -11,8 +17,7 @@ fn test_x509() {
     // println!("{:?}", cert);
     // println!("{:#?}", cert.subject().iter_common_name());
     cert.subject().iter_common_name().for_each(|c| {
-        use std::str::FromStr;
-        if c.attr_type == Oid::from_str("2.5.4.3").unwrap() {
+        if c.attr_type == *OID_COMMON_NAME {
             println!("{:?}", c.attr_value.content.as_str().unwrap());
         }
     });
@@ -25,4 +30,6 @@ fn test_x509() {
             _ => {}
         }
     }
+    println!("{:?}", cert.signature_algorithm.algorithm);
+    println!("{:?}", cert.signature_algorithm.algorithm.bytes());
 }
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