8. Protocol Numbers
The protocol number tables from Section 8 are preserved below.
8. Protocol Numbers
8.1. Message Type Numbers
The following numbers are used as message types for requests from the
client to the agent.
+------------------------------------------+----+
| SSH_AGENTC_REQUEST_IDENTITIES | 11 |
+------------------------------------------+----+
| SSH_AGENTC_SIGN_REQUEST | 13 |
+------------------------------------------+----+
| SSH_AGENTC_ADD_IDENTITY | 17 |
+------------------------------------------+----+
| SSH_AGENTC_REMOVE_IDENTITY | 18 |
+------------------------------------------+----+
| SSH_AGENTC_REMOVE_ALL_IDENTITIES | 19 |
+------------------------------------------+----+
| SSH_AGENTC_ADD_SMARTCARD_KEY | 20 |
+------------------------------------------+----+
| SSH_AGENTC_REMOVE_SMARTCARD_KEY | 21 |
+------------------------------------------+----+
| SSH_AGENTC_LOCK | 22 |
+------------------------------------------+----+
| SSH_AGENTC_UNLOCK | 23 |
+------------------------------------------+----+
| SSH_AGENTC_ADD_ID_CONSTRAINED | 25 |
+------------------------------------------+----+
| SSH_AGENTC_ADD_SMARTCARD_KEY_CONSTRAINED | 26 |
+------------------------------------------+----+
| SSH_AGENTC_EXTENSION | 27 |
+------------------------------------------+----+
Table 1
The following numbers are used as message types for replies from the
agent to the client.
+------------------------------+----+
| SSH_AGENT_FAILURE | 5 |
+------------------------------+----+
| SSH_AGENT_SUCCESS | 6 |
+------------------------------+----+
| SSH_AGENT_IDENTITIES_ANSWER | 12 |
+------------------------------+----+
| SSH_AGENT_SIGN_RESPONSE | 14 |
+------------------------------+----+
| SSH_AGENT_EXTENSION_FAILURE | 28 |
+------------------------------+----+
| SSH_AGENT_EXTENSION_RESPONSE | 29 |
+------------------------------+----+
Table 2
8.1.1. Reserved Message Type Numbers
The following message type numbers are reserved for implementations
that implement support for the legacy SSH protocol version 1: 1-4,
7-10, 15-16, and 24 (inclusive). These message numbers MAY be used
by an implementation supporting the legacy protocol but MUST NOT be
reused otherwise.
Message number 0 is also reserved and MUST NOT be used.
The range of message numbers 240-255 is reserved for Private Use
extensions to the agent protocol and MUST NOT be used by generic
implementations (see [RFC8126] for more information on Private Use).
8.2. Constraint Identifiers
The following numbers are used to identify key constraints. These
are only used in key constraints and are not sent as message numbers.
+-------------------------------+-----+
| SSH_AGENT_CONSTRAIN_LIFETIME | 1 |
+-------------------------------+-----+
| SSH_AGENT_CONSTRAIN_CONFIRM | 2 |
+-------------------------------+-----+
| SSH_AGENT_CONSTRAIN_EXTENSION | 255 |
+-------------------------------+-----+
Table 3
The constraint identifier 0 is reserved.
8.3. Signature Flags
The following numbers may be present in signature request
(SSH_AGENTC_SIGN_REQUEST) messages. These flags form a bit field by
taking the logical OR of zero or more flags.
+------------------------+------------+
| SSH_AGENT_RSA_SHA2_256 | 0x00000002 |
+------------------------+------------+
| SSH_AGENT_RSA_SHA2_512 | 0x00000004 |
+------------------------+------------+
Table 4
The flag value 1 is reserved for historical implementations.