add some notes about when to use these classmethods
diff --git a/docs/x509/reference.rst b/docs/x509/reference.rst
index 1e8aeba..399d693 100644
--- a/docs/x509/reference.rst
+++ b/docs/x509/reference.rst
@@ -1541,6 +1541,13 @@
.. versionadded:: 1.0
+ .. note::
+
+ This method should be used if the issuer certificate does not
+ contain a :class:`~cryptography.x509.SubjectKeyIdentifier`.
+ Otherwise, use
+ :meth:`~cryptography.x509.AuthorityKeyIdentifier.from_issuer_subject_key_identifier`.
+
Creates a new AuthorityKeyIdentifier instance using the public key
provided to generate the appropriate digest. This should be the
**issuer's public key**. The resulting object will contain
@@ -1572,6 +1579,11 @@
.. versionadded:: 1.3
+ .. note::
+ This method should be used if the issuer certificate contains a
+ :class:`~cryptography.x509.SubjectKeyIdentifier`. Otherwise, use
+ :meth:`~cryptography.x509.AuthorityKeyIdentifier.from_issuer_public_key`.
+
Creates a new AuthorityKeyIdentifier instance using the
SubjectKeyIdentifier from the issuer certificate. The resulting object
will contain