Cisco diffie-hellman

Which Diffie-Hellman group to use Cisco?
What is Diffie-Hellman used for in IPsec?
What is the difference between DH Group 2 and DH Group 5?
Which Diffie-Hellman group is the minimally acceptable for Cisco ASA devices?
What is the difference between DH Group 14 and 5?
Does SSH always use Diffie-Hellman?
Does IKEv2 use Diffie-Hellman?
Where is Diffie-Hellman used today?
Why do we need Diffie-Hellman?
Which DH groups to avoid?
Why is DH group used?
How does DH algorithm work?
What Diffie-Hellman DH group is being used for the DMZ Tunnel VPN?
What is Diffie-Hellman Group 20?
Why is RSA preferred over Diffie-Hellman if they are both used to establish shared key?
What is the most common use of the Diffie?
Which DH group is most secure?
Does TLS use Diffie-Hellman key exchange?
Where is Diffie-Hellman used today?
What is DH Group 14 key size?
Which DH groups to avoid?
How does DH algorithm work?

Which Diffie-Hellman group to use Cisco?

The Cisco ASA must be configured to use a Diffie-Hellman (DH) Group of 14 or greater for Internet Key Exchange (IKE) Phase 1.

What is Diffie-Hellman used for in IPsec?

Diffie-Hellman (D-H) is a public-key cryptography protocol. It allows two parties to establish a shared secret key used by encryption algorithms (DES or MD5, for example) over an insecure communications channel. D-H is used within IKE (described later in this article) to establish session keys.

What is the difference between DH Group 2 and DH Group 5?

DH group 1 consists of a 768 bit key, group 2 consists of 1024 bit key, group 5 is 1536 bit key length and group 14 is 2048 bit key length. Group 14 is the strongest and most secure of the ones just mentioned, but there are other key lengths as well.

Which Diffie-Hellman group is the minimally acceptable for Cisco ASA devices?

Cisco no longer recommends using DES, 3DES, MD5 (including HMAC variant), and Diffie-Hellman (DH) groups 1, 2 and 5; instead, you should use AES, SHA-256 and DH Groups 14 or higher. For more information about the latest Cisco cryptographic recommendations, see the Next Generation Encryption (NGE) white paper.

What is the difference between DH Group 14 and 5?

DH with 1536 bits (group 5) has 89 bits of security. DH with 2048 bits (group 14) has 103 bits of security.

Does SSH always use Diffie-Hellman?

The SSH protocol provides perfect forward secrecy by using Diffie-Hellman or elliptic curve Diffie-Hellman for every session. This differs from SSL/TLS, that is usually configured without perfect forward secrecy, even though the standard does support it.

Does IKEv2 use Diffie-Hellman?

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).

Where is Diffie-Hellman used today?

Diffie-Hellman key exchange is commonly found in security protocols, such as Transport Layer Security (TLS), Secure Shell (SSH) and IP Security (IPsec). For example, in IPsec, the encryption method is used for key generation and key rotation.

Why do we need Diffie-Hellman?

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.

Which DH groups to avoid?

DH (Diffie-Hellman) algorithms, used for key exchange, should not be used for groups with a bit value of 1024 or less.

Why is DH group used?

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.

How does DH algorithm work?

The Diffie–Hellman (DH) Algorithm is a key-exchange protocol that enables two parties communicating over public channel to establish a mutual secret without it being transmitted over the Internet. DH enables the two to use a public key to encrypt and decrypt their conversation or data using symmetric cryptography.

What Diffie-Hellman DH group is being used for the DMZ Tunnel VPN?

For branch office VPN tunnels and BOVPN virtual interfaces, the default DH group for both Phase 1 and Phase 2 is Diffie-Hellman Group 14. If the speed for tunnel initialization and rekey is not a concern, you can use a higher DH group.

What is Diffie-Hellman Group 20?

Group 20 = 384-bit EC = 192 bits of security

That is, both groups offer a higher security level than the Diffie-Hellman groups 14 (103 bits) or 5 (89 bits).

Why is RSA preferred over Diffie-Hellman if they are both used to establish shared key?

RSA keys are substantially larger than ECDH (Elliptic Curve Diffie-Hellman) keys.

What is the most common use of the Diffie?

The main purpose of the Diffie-Hellman key exchange is to securely develop shared secrets that can be used to derive keys. These keys can then be used with symmetric-key algorithms to transmit information in a protected manner.

Which DH group is most secure?

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.

Does TLS use Diffie-Hellman key exchange?

One family of encryption cipher suites used in TLS uses Diffie-Hellman key exchange.

Where is Diffie-Hellman used today?

What is DH Group 14 key size?

DH public key cryptography is used by all major VPN gateways. DH group 1 consists of a 768 bit modulus, group 2 consists of 1024 bit modulus, group 5 uses a 1536 bit modulus, and group 14 uses a 2048 bit modulus.

Which DH groups to avoid?

DH (Diffie-Hellman) algorithms, used for key exchange, should not be used for groups with a bit value of 1024 or less.