How to perform key exchange using Diffie-Hellman in Go?

To perform key exchange using Diffie-Hellman in Go, you can use the crypto/diffiehellman package available in the Go standard library. Here's an example of how to perform key exchange using Diffie-Hellman in Go:

package main

import (
	"crypto/diffiehellman"
	"crypto/rand"
	"fmt"
)

func main() {
	// Generate a random private key for Alice
	alicePrivateKey, _ := diffiehellman.GenerateKey(rand.Reader, 2048)

	// Generate a random private key for Bob
	bobPrivateKey, _ := diffiehellman.GenerateKey(rand.Reader, 2048)

	// Compute the public keys for Alice and Bob
	alicePublicKey := alicePrivateKey.PublicKey()
	bobPublicKey := bobPrivateKey.PublicKey()

	// Perform the key exchange between Alice and Bob
	aliceSharedKey, _ := diffiehellman.GenerateSharedSecret(alicePrivateKey, &bobPublicKey)
	bobSharedKey, _ := diffiehellman.GenerateSharedSecret(bobPrivateKey, &alicePublicKey)

	// Verify that Alice and Bob have the same shared secret
	fmt.Println("Alice shared key:", aliceSharedKey)
	fmt.Println("Bob shared key:", bobSharedKey)
	fmt.Println("Shared keys match:", aliceSharedKey.Cmp(bobSharedKey) == 0)
}

In this example, we first generate random private keys for both Alice and Bob using the diffiehellman.GenerateKey function. These private keys are then used to compute their respective public keys using the PublicKey method.

Next, we perform the key exchange by calling the diffiehellman.GenerateSharedSecret function with the private key of one party and the public key of the other party. This function returns the shared secret key for each party.

Finally, we verify that Alice and Bob have the same shared secret key by comparing their shared keys using the Cmp method.

Note: This example uses a 2048-bit key size, but you can choose a different key size based on your requirements.