1 files changed, 59 insertions, 1 deletions
diff --git a/src/macros.rs b/src/macros.rs
index 638d516..0333ef7 100644
--- a/src/macros.rs
+++ b/src/macros.rs
@@ -61,7 +61,7 @@ macro_rules! impl_newtype {
 
         #[allow(unused_lifetimes)]
         impl<'a> ::der::EncodeValue for $newtype {
-            fn encode_value(&self, encoder: &mut dyn ::der::Writer) -> ::der::Result<()> {
+            fn encode_value(&self, encoder: &mut impl ::der::Writer) -> ::der::Result<()> {
                 self.0.encode_value(encoder)
             }
 
@@ -78,3 +78,61 @@ macro_rules! impl_newtype {
         }
     };
 }
+
+/// Implements the AsExtension traits for every defined Extension paylooad
+macro_rules! impl_extension {
+    ($newtype:ty) => {
+        impl_extension!($newtype, critical = false);
+    };
+    ($newtype:ty, critical = $critical:expr) => {
+        impl crate::ext::AsExtension for $newtype {
+            fn critical(
+                &self,
+                _subject: &crate::name::Name,
+                _extensions: &[crate::ext::Extension],
+            ) -> bool {
+                $critical
+            }
+        }
+    };
+}
+
+/// Implements conversions between [`spki::SubjectPublicKeyInfo`] and [`SubjectKeyIdentifier`] or [`AuthorityKeyIdentifier`]
+macro_rules! impl_key_identifier {
+    ($newtype:ty, $out:expr) => {
+        #[cfg(feature = "builder")]
+        mod builder_key_identifier {
+            use super::*;
+            use der::asn1::OctetString;
+            use sha1::{Digest, Sha1};
+            use spki::SubjectPublicKeyInfoRef;
+
+            impl<'a> TryFrom<SubjectPublicKeyInfoRef<'a>> for $newtype {
+                type Error = der::Error;
+
+                fn try_from(issuer: SubjectPublicKeyInfoRef<'a>) -> Result<Self, Self::Error> {
+                    // https://datatracker.ietf.org/doc/html/rfc5280#section-4.2.1.2
+                    //
+                    //  For CA certificates, subject key identifiers SHOULD be derived from
+                    //  the public key or a method that generates unique values.  Two common
+                    //  methods for generating key identifiers from the public key are:
+
+                    //     (1) The keyIdentifier is composed of the 160-bit SHA-1 hash of the
+                    //          value of the BIT STRING subjectPublicKey (excluding the tag,
+                    //          length, and number of unused bits).
+
+                    //     (2) The keyIdentifier is composed of a four-bit type field with
+                    //          the value 0100 followed by the least significant 60 bits of
+                    //          the SHA-1 hash of the value of the BIT STRING
+                    //          subjectPublicKey (excluding the tag, length, and number of
+                    //          unused bits).
+
+                    // Here we're using the first method
+
+                    let result = Sha1::digest(issuer.subject_public_key.raw_bytes());
+                    $out(result.as_slice())
+                }
+            }
+        }
+    };
+}