===================================================================
RCS file: /cvsrepo/anoncvs/cvs/src/usr.bin/ssh/PROTOCOL.certkeys,v
retrieving revision 1.10
retrieving revision 1.15
diff -u -r1.10 -r1.15
--- src/usr.bin/ssh/PROTOCOL.certkeys	2016/05/03 10:27:59	1.10
+++ src/usr.bin/ssh/PROTOCOL.certkeys	2018/07/03 11:39:54	1.15
@@ -25,6 +25,10 @@
 acceptance of certified host keys, by adding a similar ability to
 specify CA keys in ~/.ssh/known_hosts.
 
+All certificate types include certification information along with the
+public key that is used to sign challenges. In OpenSSH, ssh-keygen
+performs the CA signing operation.
+
 Certified keys are represented using new key types:
 
     ssh-rsa-cert-v01@openssh.com
@@ -33,10 +37,18 @@
     ecdsa-sha2-nistp384-cert-v01@openssh.com
     ecdsa-sha2-nistp521-cert-v01@openssh.com
 
-These include certification information along with the public key
-that is used to sign challenges. ssh-keygen performs the CA signing
-operation.
+Two additional types exist for RSA certificates to force use of
+SHA-2 signatures (SHA-256 and SHA-512 respectively):
 
+    rsa-sha2-256-cert-v01@openssh.com
+    rsa-sha2-512-cert-v01@openssh.com
+
+These RSA/SHA-2 types should not appear in keys at rest or transmitted
+on their wire, but do appear in a SSH_MSG_KEXINIT's host-key algorithms
+field or in the "public key algorithm name" field of a "publickey"
+SSH_USERAUTH_REQUEST to indicate that the signature will use the
+specified algorithm.
+
 Protocol extensions
 -------------------
 
@@ -100,9 +112,9 @@
 
 ECDSA certificate
 
-    string    "ecdsa-sha2-nistp256-v01@openssh.com" |
-              "ecdsa-sha2-nistp384-v01@openssh.com" |
-              "ecdsa-sha2-nistp521-v01@openssh.com"
+    string    "ecdsa-sha2-nistp256-cert-v01@openssh.com" |
+              "ecdsa-sha2-nistp384-cert-v01@openssh.com" |
+              "ecdsa-sha2-nistp521-cert-v01@openssh.com"
     string    nonce
     string    curve
     string    public_key
@@ -174,7 +186,7 @@
 
     valid after <= current time < valid before
 
-criticial options is a set of zero or more key options encoded as
+critical options is a set of zero or more key options encoded as
 below. All such options are "critical" in the sense that an implementation
 must refuse to authorise a key that has an unrecognised option.
 
@@ -192,12 +204,13 @@
 The reserved field is currently unused and is ignored in this version of
 the protocol.
 
-signature key contains the CA key used to sign the certificate.
-The valid key types for CA keys are ssh-rsa, ssh-dss and the ECDSA types
-ecdsa-sha2-nistp256, ecdsa-sha2-nistp384, ecdsa-sha2-nistp521. "Chained"
-certificates, where the signature key type is a certificate type itself
-are NOT supported. Note that it is possible for a RSA certificate key to
-be signed by a DSS or ECDSA CA key and vice-versa.
+The signature key field contains the CA key used to sign the
+certificate. The valid key types for CA keys are ssh-rsa,
+ssh-dss, ssh-ed25519 and the ECDSA types ecdsa-sha2-nistp256,
+ecdsa-sha2-nistp384, ecdsa-sha2-nistp521. "Chained" certificates, where
+the signature key type is a certificate type itself are NOT supported.
+Note that it is possible for a RSA certificate key to be signed by a
+Ed25519 or ECDSA CA key and vice-versa.
 
 signature is computed over all preceding fields from the initial string
 up to, and including the signature key. Signatures are computed and
@@ -223,6 +236,9 @@
 "critical", if an implementation does not recognise a option
 then the validating party should refuse to accept the certificate.
 
+Custom options should append the originating author or organisation's
+domain name to the option name, e.g. "my-option@example.com".
+
 No critical options are defined for host certificates at present. The
 supported user certificate options and the contents and structure of
 their data fields are:
@@ -254,6 +270,9 @@
 If an implementation does not recognise an extension, then it should
 ignore it.
 
+Custom options should append the originating author or organisation's
+domain name to the option name, e.g. "my-option@example.com".
+
 No extensions are defined for host certificates at present. The
 supported user certificate extensions and the contents and structure of
 their data fields are:
@@ -284,4 +303,4 @@
                                       of this script will not be permitted if
                                       this option is not present.
 
-$OpenBSD: PROTOCOL.certkeys,v 1.10 2016/05/03 10:27:59 djm Exp $
+$OpenBSD: PROTOCOL.certkeys,v 1.15 2018/07/03 11:39:54 djm Exp $