update prose for from_issuer_public_key
diff --git a/docs/x509/reference.rst b/docs/x509/reference.rst
index a05be16..930c7f9 100644
--- a/docs/x509/reference.rst
+++ b/docs/x509/reference.rst
@@ -1166,10 +1166,14 @@
Creates a new AuthorityKeyIdentifier instance using the public key
provided to generate the appropriate digest. This should be the
- **issuer public key**. The resulting object will contain a
- :attr:`~cryptography.x509.AuthorityKeyIdentifier.key_identifier`.
- The generated digest is the SHA1 hash of the ``subjectPublicKey`` A
- SN.1 bit string. This is the first recommendation in :rfc:`5280`
+ **issuer's public key**. The resulting object will contain
+ :attr:`~cryptography.x509.AuthorityKeyIdentifier.key_identifier`, but
+ :attr:`~cryptography.x509.AuthorityKeyIdentifier.authority_cert_issuer`
+ and
+ :attr:`~cryptography.x509.AuthorityKeyIdentifier.authority_cert_serial_number`
+ will be None.
+ The generated ``key_identifier`` is the SHA1 hash of the ``subjectPublicKey``
+ ASN.1 bit string. This is the first recommendation in :rfc:`5280`
section 4.2.1.2.
:param certificate: The issuing :class:`~cryptography.x509.Certificate`.