[PATCH] Document transfer of ed25519 secret keys to the ssh-agent

[Daniel Kahn Gillmor]

This documentation is based on sshkey_private_serialize() in sshkey.c,
which is eventually called by ssh-add.
---
 PROTOCOL.agent | 25 +++++++++++++++++++++++--
 1 file changed, 23 insertions(+), 2 deletions(-)

diff --git a/PROTOCOL.agent b/PROTOCOL.agent
index c386d16..5188225 100644
--- a/PROTOCOL.agent
+++ b/PROTOCOL.agent
@@ -252,13 +252,34 @@ RSA certificates may be added with this request:
 	string			key_comment
 	constraint[]		key_constraints
 
+ED25519 keys may be added with this request:
+
+	byte			SSH2_AGENTC_ADD_IDENTITY or
+				SSH2_AGENTC_ADD_ID_CONSTRAINED
+	string			"ssh-ed25519"
+	mpint			ed25519_pk
+	mpint			ed25519_sk
+	string			key_comment
+	constraint[]		key_constraints
+
+ED25519 certificates may be added with this request:
+
+	byte			SSH2_AGENTC_ADD_IDENTITY or
+				SSH2_AGENTC_ADD_ID_CONSTRAINED
+	string			"ssh-ed25519-cert-v01 at openssh.com"
+	string			certificate
+	mpint			ed25519_pk
+	mpint			ed25519_sk
+	string			key_comment
+	constraint[]		key_constraints
+
 Note that the 'rsa_p' and 'rsa_q' parameters are sent in the reverse
 order to the protocol 1 add keys message. As with the corresponding
 protocol 1 "add key" request, the private key is overspecified to avoid
 redundant processing.
 
-For DSA, ECDSA and RSA key add requests, "key_constraints" may only be
-present if the request type is SSH2_AGENTC_ADD_ID_CONSTRAINED.
+For DSA, ECDSA, RSA, and ED25519 key add requests, "key_constraints" may
+only be present if the request type is SSH2_AGENTC_ADD_ID_CONSTRAINED.
 
 The agent will reply with a SSH_AGENT_SUCCESS if the key has been
 successfully added or a SSH_AGENT_FAILURE if an error occurred.
-- 
2.8.1