(Go) How to Generate an Elliptic Curve Shared Secret

Demonstrates how to generate an ECC (Elliptic Curve Cryptography) shared secret. Imagine a cilent has one ECC private key, the server has another. A shared secret is computed by each side providing it's public key to the other. The private keys are kept private.

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    // This example requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    // This example includes both client-side and server-side code.
    // Each code segment is marked as client-side or server-side.
    // Imagine these segments are running on separate computers...

    var success bool

    // -----------------------------------------------------------------
    // (Client-Side) Generate an ECC key, save the public part to a file.
    // -----------------------------------------------------------------
    prngClient := chilkat.NewPrng()
    eccClient := chilkat.NewEcc()
    privKeyClient := eccClient.GenEccKey("secp256r1",prngClient)
    if eccClient.LastMethodSuccess() != true {
        fmt.Println(eccClient.LastErrorText())
        prngClient.DisposePrng()
        eccClient.DisposeEcc()
        return
    }

    pubKeyClient := privKeyClient.GetPublicKey()
    pubKeyClient.SavePemFile(false,"qa_output/eccClientPub.pem")
    pubKeyClient.DisposePublicKey()

    // -----------------------------------------------------------------
    // (Server-Side) Generate an ECC key, save the public part to a file.
    // -----------------------------------------------------------------
    prngServer := chilkat.NewPrng()
    eccServer := chilkat.NewEcc()
    privKeyServer := eccServer.GenEccKey("secp256r1",prngServer)
    if eccServer.LastMethodSuccess() != true {
        fmt.Println(eccServer.LastErrorText())
        prngClient.DisposePrng()
        eccClient.DisposeEcc()
        prngServer.DisposePrng()
        eccServer.DisposeEcc()
        return
    }

    pubKeyServer := privKeyServer.GetPublicKey()
    pubKeyServer.SavePemFile(false,"qa_output/eccServerPub.pem")
    pubKeyServer.DisposePublicKey()

    // -----------------------------------------------------------------
    // (Client-Side) Generate the shared secret using our private key, and the other's public key.
    // -----------------------------------------------------------------

    // Imagine that the server sent the public key PEM to the client.
    // (This is simulated by loading the server's public key from the file.
    pubKeyFromServer := chilkat.NewPublicKey()
    pubKeyFromServer.LoadFromFile("qa_output/eccServerPub.pem")
    sharedSecret1 := eccClient.SharedSecretENC(privKeyClient,pubKeyFromServer,"base64")
    privKeyClient.DisposePrivateKey()

    // -----------------------------------------------------------------
    // (Server-Side) Generate the shared secret using our private key, and the other's public key.
    // -----------------------------------------------------------------

    // Imagine that the client sent the public key PEM to the server.
    // (This is simulated by loading the client's public key from the file.
    pubKeyFromClient := chilkat.NewPublicKey()
    pubKeyFromClient.LoadFromFile("qa_output/eccClientPub.pem")
    sharedSecret2 := eccServer.SharedSecretENC(privKeyServer,pubKeyFromClient,"base64")
    privKeyServer.DisposePrivateKey()

    // ---------------------------------------------------------
    // Examine the shared secrets.  They should be the same.
    // Both sides now have a secret that only they know.
    // ---------------------------------------------------------
    fmt.Println(*sharedSecret1)
    fmt.Println(*sharedSecret2)

    prngClient.DisposePrng()
    eccClient.DisposeEcc()
    prngServer.DisposePrng()
    eccServer.DisposeEcc()
    pubKeyFromServer.DisposePublicKey()
    pubKeyFromClient.DisposePublicKey()