What is Diffie-Hellman Group 24?
If you are using encryption or authentication algorithms with a 128-bit key, use Diffie-Hellman groups 19, 20. RFC 5114 Sec 4 states DH Group 24 strength is about equal to a modular key that is 2048-bits long, that is not strong enough to protect 128 or 256-bit AES, so I also mark that as AVOID.
What are Diffie-Hellman groups?
Diffie-Hellman Groups are used to determine the strength of the key used in the Diffie-Hellman key exchange process. Higher Diffie-Hellman Group numbers are more secure, but Higher Diffie-Hellman Groups require additional processing resources to compute the key.
What is Diffie-Hellman group exchange?
Diffie–Hellman key exchange is a method of securely exchanging cryptographic keys over a public channel and was one of the first public-key protocols as conceived by Ralph Merkle and named after Whitfield Diffie and Martin Hellman. Diffie–Hellman is used to secure a variety of Internet services.
What is diffie-hellman group1 sha1?
The “diffie-hellman-group1-sha1” method specifies the Diffie-Hellman key exchange with SHA-1 as HASH, and Oakley Group 2 [RFC2409] (1024- bit MODP Group). This method MUST be supported for interoperability as all of the known implementations currently support it.
What is diffie-hellman used for?
The Diffie-Hellman algorithm will be used to establish a secure communication channel. This channel is used by the systems to exchange a private key. This private key is then used to do symmetric encryption between the two systems.
What DH Group 19?
group19 —256-bit random Elliptic Curve Groups modulo a Prime (ECP groups) algorithm. group20 —384-bit random ECP groups algorithm. group21 —521-bit random ECP groups algorithm. group24 —2048-bit MODP Group with 256-bit prime order subgroup.
What is a generator in Diffie Hellman?
Diffie-Hellman-Key-Exchange In the beginning we need to choose a group \mathbb{G} . The naive and insecure DH-KX now takes a generator g from that group (a generator is an element that generates the entire group, meaning that it’s powers are all the group-elements).
What is KexAlgorithms in SSH?
KexAlgorithms : the key exchange methods that are used to generate per-connection keys. HostkeyAlgorithms : the public key algorithms accepted for an SSH server to authenticate itself to an SSH client. Ciphers : the ciphers to encrypt the connection.
When to use Diffie Hellman ( DH ) Group?
AES should use a stronger DH Group. If you are using encryption or authentication algorithms with a 128-bit key, use Diffie-Hellman groups 19, 20. If you are using encryption or authentication algorithms with a 256-bit key or higher, use Diffie-Hellman group 21.
Which is more secure MoDP or Diffie Hellman?
Diffie-Hellman (DH) groups determine the strength of the key used in the key exchange process. Within a group type (MODP or ECP), higher Diffie-Hellman group numbers are usually more secure.
What are the Diffie Hellman groups for encryption?
Diffie Hellman Groups. If you are using encryption or authentication algorithms with a 128-bit key, use Diffie-Hellman groups 5, 14, 19, 20 or 24. If you are using encryption or authentication algorithms with a 256-bit key or higher, use Diffie-Hellman group 21 or 24.
How is Diffie Hellman used in a VPN?
Diffie-Hellman (DH) allows two devices to establish a shared secret over an unsecure network. In terms of VPN it is used in the in IKE or Phase1 part of setting up the VPN tunnel. There are multiple Diffie-Hellman Groups that can be configured in an IKEv2 policy on a Cisco ASA running 9.1(3).