diff --git a/src/fingerprint/error.rs b/src/fingerprint/error.rs
index 2b08cd9..8149a75 100644
--- a/src/fingerprint/error.rs
+++ b/src/fingerprint/error.rs
@@ -4,6 +4,7 @@ use {std::fmt, x509_parser::prelude::X509Error};
 /// Errors which can occur when fingerprinting a certificate
 pub enum Error {
     Fmt,
+    InvalidForDate,
     X509(X509Error),
 }
 
@@ -11,6 +12,7 @@ impl fmt::Display for Error {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match self {
             Self::Fmt => write!(f, "FingerPrint: format error"),
+            Self::InvalidForDate => write!(f, "FingerPrint: invalid for date"),
             Self::X509(e) => write!(f, "FingerPrint: {e}"),
         }
     }
@@ -19,8 +21,8 @@ impl fmt::Display for Error {
 impl std::error::Error for Error {
     fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
         match self {
-            Self::Fmt => None,
             Self::X509(e) => Some(e),
+            _ => None,
         }
     }
 }
diff --git a/src/fingerprint/mod.rs b/src/fingerprint/mod.rs
index d25c7c8..7fc4fe4 100644
--- a/src/fingerprint/mod.rs
+++ b/src/fingerprint/mod.rs
@@ -1,21 +1,37 @@
-use {digest::Digest, rustls::Certificate, sha2::Sha256, std::fmt::Write, x509_parser::prelude::*};
+use {digest::Digest, rustls::Certificate, sha2::Sha256, std::{io::Read, fmt::Write}, x509_parser::prelude::*};
 
 mod error;
 pub use error::Error;
 
 /// Creates an sha256 fingerprint for a certificate
-pub trait Fingerprint {
+pub trait GetFingerprint {
     type Error;
 
-    fn fingerprint(&self) -> Result<(String, String), Self::Error>;
+    fn fingerprint(&self) -> Result<Fingerprint, Self::Error>;
 }
 
-impl Fingerprint for Certificate {
+pub struct Fingerprint {
+    pub names: Vec<String>,
+    pub fingerprint: String,
+}
+
+impl GetFingerprint for Certificate {
     type Error = Error;
 
-    fn fingerprint(&self) -> Result<(String, String), Self::Error> {
+    fn fingerprint(&self) -> Result<Fingerprint, Self::Error> {
         let (_, pk) = X509Certificate::from_der(self.as_ref())?;
-        let subject = pk.subject().to_string();
+        let subject = pk.subject();
+        let mut names = vec![];
+        subject.iter_common_name().for_each(|n| {
+            let mut val = n.attr_value().data;
+            let mut name = String::new();
+            if let Ok(_) = val.read_to_string(&mut name) {
+                names.push(name);
+            }
+        });
+        if !pk.validity().is_valid() {
+            return Err(Error::InvalidForDate);
+        }
         let key = pk.public_key().subject_public_key.as_ref();
         let mut hasher = Sha256::new();
         hasher.update(key);
@@ -24,6 +40,6 @@ impl Fingerprint for Certificate {
         for c in res {
             write!(s, "{c:02x}")?;
         }
-        Ok((subject[3..].to_string(), s))
+        Ok(Fingerprint { names, fingerprint: s })
     }
 }
diff --git a/src/prelude.rs b/src/prelude.rs
index 3b93bf8..8f57e98 100644
--- a/src/prelude.rs
+++ b/src/prelude.rs
@@ -1,6 +1,6 @@
 pub use super::{
     certificate_store::CertificateStore,
-    fingerprint::{Error as FingerprintError, Fingerprint},
+    fingerprint::{Error as FingerprintError, Fingerprint, GetFingerprint},
     host::{Error as ParseHostError, Host},
     //receiver,
     request::{Error as ParseRequestError, Request},
diff --git a/src/sender/verifier.rs b/src/sender/verifier.rs
index f1893b4..a0bda39 100644
--- a/src/sender/verifier.rs
+++ b/src/sender/verifier.rs
@@ -1,5 +1,5 @@
 use {
-    crate::prelude::{CertificateStore, Fingerprint},
+    crate::prelude::{CertificateStore, Fingerprint, GetFingerprint},
     rustls::{
         client::{ServerCertVerified, ServerCertVerifier},
         Certificate,
@@ -40,17 +40,22 @@ impl<S: CertificateStore> ServerCertVerifier for Verifier<S> {
         let mut store = self.store.lock().unwrap();
         if let Some(fingerprint) = store.get_certificate(&name) {
             // TODO: needs a lot more checking for certificate validity
-            if fingerprint == fp.1 && name == fp.0 {
-                return Ok(ServerCertVerified::assertion());
+            if fingerprint == fp.fingerprint {
+                for n in fp.names {
+                    if n == name {
+                        return Ok(ServerCertVerified::assertion());
+                    }
+                }
+                Err(rustls::Error::InvalidCertificate(rustls::CertificateError::NotValidForName))
+            } else {
+                Err(rustls::Error::InvalidCertificate(rustls::CertificateError::NotValidForName))
             }
         } else {
             if !store.contains_certificate(&name) {
-                let _key = store.borrow_mut().insert_certificate(&name, &fp.1);
+                let _key = store.borrow_mut().insert_certificate(&name, &fp.fingerprint);
             }
+            return Ok(ServerCertVerified::assertion());
         }
-        Err(rustls::Error::General(
-            "Unrecognized certificate".to_string(),
-        ))
     }
 }