diff --git a/src/sample_cert2.pem b/src/sample_cert2.pem
new file mode 100644
index 0000000..e1ab52a
--- /dev/null
+++ b/src/sample_cert2.pem
@@ -0,0 +1,14 @@
+-----BEGIN CERTIFICATE-----
+MIICFDCCAXWgAwIBAgIUVHKGvbVXHNU88FnAjfsrXQdGDDMwCgYIKoZIzj0EAwIw
+ITEfMB0GA1UEAwwWSGF0dGVyIFRlc3QgQ0EgRUMgUm9vdDAeFw0xOTA2MDcwMDAw
+MDBaFw0zOTA2MDcwMDAwMDBaMCkxJzAlBgNVBAMMHkhhdHRlciBUZXN0IEludGVy
+bWVkaWF0ZSBFQyBDQTB2MBAGByqGSM49AgEGBSuBBAAiA2IABPoKGtj8lGhDKb+l
+p2LBIJ7C+UmxiLqg1F0n5w3041lLDq28688HLx6yzFuOnQo6UrbPvjvjifgqukq8
+upIBlfe6MYh5s8HJytwcutaWFrNMXtW+1jTTno9y0LM8cTPA2KNmMGQwDgYDVR0P
+AQH/BAQDAgEGMBIGA1UdEwEB/wQIMAYBAf8CAQAwHQYDVR0OBBYEFHMGwhbHXYJn
+eh0XlzTk9zSv+jhVMB8GA1UdIwQYMBaAFLshgqxgJX87yP8C1wIFFoSMtQZuMAoG
+CCqGSM49BAMCA4GMADCBiAJCAcHOv7ETFyrc7dyVBllqC/CPX1SggQ92Zwn8Mzya
+EW1Y55uJaR/02Q2F+4h4dUtBSLjchyYhWuWC7QD79hFZD6v6AkIAhWZcyoN2n2dG
+LPoQrggrN+nP/zhUIlqrkwQLni8Jj2FRc1bUnzP4s5t9W6la7q3c6f8Lj+c5lRvW
+DH970YSv9fA=
+-----END CERTIFICATE-----
\ No newline at end of file
diff --git a/src/x509.rs b/src/x509.rs
index fe4b2da..2ea9f54 100644
--- a/src/x509.rs
+++ b/src/x509.rs
@@ -1,35 +1,107 @@
 use x509_parser::parse_x509_certificate;
 use x509_parser::pem::parse_x509_pem;
-use x509_parser::extensions::ParsedExtension;
+use x509_parser::extensions::{ParsedExtension, GeneralName};
 use x509_parser::der_parser::oid::Oid;
 use std::str::FromStr;
+use rust_util::XResult;
+use x509_parser::der_parser::der::parse_der_bitstring;
+use x509_parser::der_parser::parse_der;
 
 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();
+    static ref OID_ECDSA_WITH_SHA256: Oid<'static> = Oid::from_str("1.2.840.10045.4.3.2").unwrap();
+
+    static ref OID_EC_PUBLIC_KEY: Oid<'static> = Oid::from_str("1.2.840.10045.2.1").unwrap();
+
+    static ref OID_SECP256R1: Oid<'static> = Oid::from_str("1.2.840.10045.3.1.7").unwrap();
+    static ref OID_SECP384R1: Oid<'static> = Oid::from_str("1.3.132.0.34").unwrap();
+    static ref OID_SECP521R1: Oid<'static> = Oid::from_str("1.3.132.0.35").unwrap();
+}
+
+#[derive(Debug, Clone, Copy)]
+pub enum X509IssuerAlgo {
+    RsaWithSha256,
+    EcdsaWithSha256,
+}
+
+pub enum X509EcPublicKeyAlgo {
+    Secp256r1,
+    Secp384r1,
+    Secp521r1,
+}
+
+pub enum X509PublicKeyAlgo {
+    EcKey(X509EcPublicKeyAlgo)
+}
+
+#[derive(Debug, Clone)]
+pub struct X509Certificate {
+    pub issuer_algo: X509IssuerAlgo,
+    pub common_name: String,
+    pub alt_names: Vec<String>,
+}
+
+pub fn parse_x500(pem_id: &str, pem: &str) -> XResult<X509Certificate> {
+    let (_, der) = opt_result!(parse_x509_pem(pem.as_bytes()), "Parse pem: {} to der failed: {}", pem_id);
+    let (_, cert) = opt_result!(parse_x509_certificate(der.contents.as_slice()), "Parse cert: {} failed: {}", pem_id);
+
+    let mut common_name = None;
+    cert.subject().iter_common_name().for_each(|c| {
+        if c.attr_type == *OID_COMMON_NAME {
+            common_name = c.attr_value.content.as_str().ok();
+        }
+    });
+    let cert_algorithm_oid = &cert.signature_algorithm.algorithm;
+    let issuer_algo = if cert_algorithm_oid == &*OID_RSA_WITH_SHA256 {
+        X509IssuerAlgo::RsaWithSha256
+    } else if cert_algorithm_oid == &*OID_ECDSA_WITH_SHA256 {
+        X509IssuerAlgo::EcdsaWithSha256
+    } else {
+        return simple_error!("Unknown x509 algorithm oid: {:?}", cert_algorithm_oid);
+    };
+    let common_name = match common_name {
+        None => return simple_error!("Cannot find common name from: {}", pem_id),
+        Some(common_name) => common_name.to_string(),
+    };
+    let mut alt_names = vec![];
+    for (oid, ext) in cert.extensions().iter() {
+        if let ParsedExtension::SubjectAlternativeName(san) = ext.parsed_extension() {
+            for name in &san.general_names {
+                match name {
+                    GeneralName::DNSName(dns_name) => alt_names.push(dns_name.to_string()),
+                    n => warning!("Unknown general name from: {}, name: {:?}", pem_id, n),
+                }
+            }
+        }
+    }
+    let public_key_algo_oid = &cert.tbs_certificate.subject_pki.algorithm.algorithm;
+    let public_key_algo = if public_key_algo_oid == &*OID_EC_PUBLIC_KEY {
+        // TODO ...
+        let ec_public_key_algo_oid = cert.tbs_certificate.subject_pki.algorithm.parameters.unwrap().content.as_oid().unwrap();
+    };
+
+
+    Ok(X509Certificate {
+        issuer_algo,
+        common_name,
+        alt_names,
+    })
 }
 
 #[test]
 fn test_x509() {
-    let pem = include_str!("sample_cert.pem");
+    let pem = include_str!("sample_cert2.pem");
     let (_, parsed_pem) = parse_x509_pem(pem.as_bytes()).unwrap();
     let (_, cert) = parse_x509_certificate(parsed_pem.contents.as_slice()).unwrap();
-    // println!("{:?}", cert);
-    // println!("{:#?}", cert.subject().iter_common_name());
-    cert.subject().iter_common_name().for_each(|c| {
-        if c.attr_type == *OID_COMMON_NAME {
-            println!("{:?}", c.attr_value.content.as_str().unwrap());
-        }
-    });
-    // println!("{:#?}", cert.extensions());
-    for (oid, ext) in cert.extensions().iter() {
-        match ext.parsed_extension() {
-            ParsedExtension::SubjectAlternativeName(san) => {
-                println!("{:?}", san);
-            }
-            _ => {}
-        }
-    }
-    println!("{:?}", cert.signature_algorithm.algorithm);
-    println!("{:?}", cert.signature_algorithm.algorithm.bytes());
+
+    println!("{:#?}", parse_x500("id", pem));
+
+    println!("{:?}", cert.tbs_certificate.signature);
+    println!("{:?}", cert.tbs_certificate.subject_pki);
+    println!("{:?}", cert.tbs_certificate.subject_pki.algorithm.algorithm);
+    println!("{:?}", cert.tbs_certificate.subject_pki.algorithm.parameters.unwrap().content.as_oid().unwrap());
+
+    let a = parse_der(cert.tbs_certificate.subject_pki.subject_public_key.data);
+    println!("{:?}", a);
 }
\ No newline at end of file