6.5. Key Exchange Methods

6.5. Key Exchange Methods

The key exchange method specifies how one-time session keys are generated for encryption and for authentication, and how the server authentication is done.

Two REQUIRED key exchange methods have been defined:

diffie-hellman-group1-sha1 REQUIRED
diffie-hellman-group14-sha1 REQUIRED

These methods are described in Section 8.

Additional methods may be defined as specified in [SSH-NUMBERS]. The name "diffie-hellman-group1-sha1" is used for a key exchange method using an Oakley group, as defined in [RFC2409]. SSH maintains its own group identifier space that is logically distinct from Oakley [RFC2412] and IKE; however, for one additional group, the Working Group adopted the number assigned by [RFC3526], using diffie-hellman-group14-sha1 for the name of the second defined group. Implementations should treat these names as opaque identifiers and should not assume any relationship between the groups used by SSH and the groups defined for IKE.