diff --git a/src/cert.rs b/src/cert.rs
index cf93e5c8..3450c894 100644
--- a/src/cert.rs
+++ b/src/cert.rs
@@ -116,7 +116,7 @@ impl<'a> Cert<'a> {
                             der::Tag::Sequence,
                             Error::BadDer,
                             |extension| {
-                                remember_cert_extension(&mut cert, &Extension::parse(extension)?)
+                                remember_cert_extension(&mut cert, &Extension::from_der(extension)?)
                             },
                         )
                     },
diff --git a/src/crl.rs b/src/crl.rs
index 9616a414..1d4c2948 100644
--- a/src/crl.rs
+++ b/src/crl.rs
@@ -351,7 +351,7 @@ impl<'a> FromDer<'a> for BorrowedCertRevocationList<'a> {
                             //   that the application cannot process, then the application MUST NOT
                             //   use that CRL to determine the status of certificates.  However,
                             //   applications may ignore unrecognized non-critical extensions.
-                            crl.remember_extension(&Extension::parse(extension)?)
+                            crl.remember_extension(&Extension::from_der(extension)?)
                         },
                     )
                 },
@@ -537,7 +537,7 @@ impl<'a> FromDer<'a> for BorrowedRevokedCert<'a> {
                     //   process, then the application MUST NOT use that CRL to determine the
                     //   status of any certificates.  However, applications may ignore
                     //   unrecognized non-critical CRL entry extensions.
-                    revoked_cert.remember_extension(&Extension::parse(ext_der)?)
+                    revoked_cert.remember_extension(&Extension::from_der(ext_der)?)
                 })?;
                 if reader.at_end() {
                     break;
diff --git a/src/x509.rs b/src/x509.rs
index 853d2056..7944dce9 100644
--- a/src/x509.rs
+++ b/src/x509.rs
@@ -23,17 +23,6 @@ pub(crate) struct Extension<'a> {
 }
 
 impl<'a> Extension<'a> {
-    pub(crate) fn parse(der: &mut untrusted::Reader<'a>) -> Result<Extension<'a>, Error> {
-        let id = der::expect_tag_and_get_value(der, der::Tag::OID)?;
-        let critical = bool::from_der(der)?;
-        let value = der::expect_tag_and_get_value(der, der::Tag::OctetString)?;
-        Ok(Extension {
-            id,
-            critical,
-            value,
-        })
-    }
-
     pub(crate) fn unsupported(&self) -> Result<(), Error> {
         match self.critical {
             true => Err(Error::UnsupportedCriticalExtension),
@@ -42,6 +31,19 @@ impl<'a> Extension<'a> {
     }
 }
 
+impl<'a> FromDer<'a> for Extension<'a> {
+    fn from_der(reader: &mut untrusted::Reader<'a>) -> Result<Self, Error> {
+        let id = der::expect_tag_and_get_value(reader, der::Tag::OID)?;
+        let critical = bool::from_der(reader)?;
+        let value = der::expect_tag_and_get_value(reader, der::Tag::OctetString)?;
+        Ok(Extension {
+            id,
+            critical,
+            value,
+        })
+    }
+}
+
 pub(crate) fn set_extension_once<T>(
     destination: &mut Option<T>,
     parser: impl Fn() -> Result<T, Error>,