Table of Contents

## Is Diffie-Hellman Group 24 safe?

If you are using encryption or authentication algorithms with a 256-bit key or higher, use Diffie-Hellman group 21. 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, you should stay away from 24.

## How do I choose a Diffie-Hellman group?

IBM “Guideline: 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 key length of 256 bits or greater, use Diffie-Hellman group 21.”

## Is Diffie-Hellman Group 2 secure?

Using Diffie-Hellman alongside authentication algorithms is a secure and approved solution. Diffie-Hellman public key cryptography is used by all major VPN gateway’s today, supporting Diffie-Hellman groups 1,2, 5, 14 as well as others.

## What is Diffie-Hellman groups?

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. Diffie-Hellman performance can vary by WatchGuard hardware model.

## Which DH group should I use?

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.

## How does Diffie-Hellman key exchange work?

In the Diffieâ€“Hellman key exchange scheme, each party generates a public/private key pair and distributes the public key. After obtaining an authentic copy of each other’s public keys, Alice and Bob can compute a shared secret offline. The shared secret can be used, for instance, as the key for a symmetric cipher.

## What is Diffie-Hellman group used for?

Diffie-Hellman (DH) is a key exchange algorithm that allows two devices to establish a shared secret over an unsecured network without having shared anything beforehand. Diffie-Hellman is used in IKE, TLS, SSH, SMIME, and likely other protocols.

## What is the best Diffie-Hellman group?

## Where is Diffie-Hellman used?

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 is Diffie-Hellman used for?

## How do you decrypt Diffie-Hellman?

Encrypt and decrypt a number

- Select the shared numbers. select a large prime number P.
- Select the private key and share the public key. Let’s look at two users, Alice and Bob.
- Compute the super key for encoding and decoding. Alice computes her super key as X = B^a mod P.
- Use the superkey to encrypt and decrypt.

## How do I make my Diffie-Hellman key exchange protocol secure?

There are two methods commonly used to agree on shared secrets: have one party use some long-term asymmetric key to encrypt the secret and send it to the owner of the key (like in an RSA key exchange), or have both parties exchange messages that contribute to the computed shared secret (what we call Diffie-Hellman key …