AES and Diffie-Hellman

[José Manuel Romero Ximil]

I am using Crypto++ 4.2. My program uses DH and I don't know how to generate a symmetric key (AES) from Diffie-Hellman

 

Could you help me?

 

Jose Manuel Romero

[Andrew Finkenstadt]

Let us suppose that you've used DH to exchange a secret key.

 

You now want both sides to come to some agreement on a specific AES "session" key.

 

To my mind, you could do something as simple as take the MD5 or SHA-1 hash of the secret key to come up with the session key.

 

If you need to generate a schedule of AES keys, you could do something as simple as taking the MD5 or SHA-1 hash of the secret key concatenated with a counter starting at an agreed-upon initial value to come up with the schedule of session keys.

 

Does that help?

 

Andy

[José Manuel Romero Ximil]

Thank you.