• The Diffie-Hellman method works best if p = 2q+1 where q is also a prime. (For example, 5 and 11 are prime and 11 = 2 x 5 + 1.) Then half the integers 1,2.,p-1 are generators, and it is possible to check whether g is a.
• The Diffie-Hellman key exchange algorithm was first published in 1976 by Whitfield Diffie and Martin Hellman, although the algorithm had been invented a few years earlier by the British government intelligence agency GCHQ but was kept classified.

String Hash Calculator String HMAC Calculator One-Time Password Calculator. Base64 Converter Bitcoin Address Generator. Diffie-Hellman Key Exchange. Diffie-Hellman key exchange allows two parties to generate a shared secret over an insecure channel.

Diffie-Hellman key exchange allows two parties to generate a shared secret over an insecure channel.

You

Partner

Description

This tool will generate a key pair for you, of which you can send the public key to a partner. Once your partner sends you their public key, paste it into their public key box. If done successfully, you two should have an identical shared secret. You may use the shared secret to encrypt messages to each other, possibly by using the AES String Encryption and Decryption tool.

Do It Yourself

OpenSSL can help you perform a Diffie-Hellman key exchange, but it is not directly compatible with this tool. The principle, however, is the same.

During this process, we will need to generate 5 elements before deriving a shared secret:

• A common base
• Partner 1's private key
• Partner 1's public key
• Partner 2's private key
• Partner 2's public key

Generate a Common Base

Use this command to generate a common base, dhp.pem. This DH Parameters key can be shared in a public manner between the two parties. It is not a secret. The library used by CryptoTools.net uses a constant value for its base.

Partner 1's Key Pair

Partner 1 should be in possession of the dhp.pem file, then they can generate their private and public keys, dhpriv1.pem and dhpub1.pem, respectively.

Partner 2's Key Pair

Likewise, Partner 2 should be in posession of the same dhp.pem file and generate their own private and public keys.

Derive Shared Secret

Partner 1 should share dhpub1.pem with Partner 2, and Partner 2 should share dhpub2.pem with Partner 1. Once they have exchanged public keys, they may derive the shared secret. Partner 1's copy of the shared secret will be named shared1.bin, and Partner 2's will be named shared2.bin.

The content of files shared1.bin and shared2.bin should be exactly the same. Since they are binary files and not easily readable by humans, you may verify that they are the same like so:

[Back] Diffie-Hellman is a standard method of Alice and Bob being able to communicate, and end up with the same secret encryption key. It is used in many applications, and uses two numbers (G and N) for the first part of the calculation (of which N must be a prime number):

Diffie-hellman Key Agreement Calculator

[Related Lecture] [Tutorial] [Software Tutorial][Software Lecture] [Theory][Blog] [Picking G value]

Next Bob and Alice will generate two random numbers (X and Y), calculate an X value and a Y value, respectively:

Diffie-hellman Calculator

Bob's X Value	Alice's Y value
Bob's random value	Alice's random value
Bob's A value	Alice's B value
A=G^x mod N	B=G^y mod N

Diffie Hellman Merkle Key Exchange Calculator

and Bob will send his A value to Alice, and Alice will send her B value to Bob, and they now re-calculate the values to generate the same shared key:

Diffie Hellman Key Exchange Calculator

Bob's Key	Alice's Key
Key=B^x mod N	Key=A^y mod N