DavidBenko / DBDiffieHellmanAndroid

Elliptic Curve Diffie Hellman Key Exchange over HTTP on Android

DBDiffieHellmanAndroid

Elliptic Curve Diffie Hellman Key Exchange over HTTP on Android

Example Use

public class MainActivity extends ActionBarActivity implements DiffieHellmanProvider {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        /*
         * Do ECDH Exchange Here
         */

        DiffieHellman dh = new DiffieHellman(this); // Create DiffieHellman, passing in a provider
        dh.keyExchange(new DHCallback() {
            @Override
            public void onComplete(String key, String salt) throws GeneralSecurityException {
                // Exchange is complete - do something with key and salt
                // Server can compute the same key using this salt and same number of rounds
                // Default is PBKDF2, 20000 rounds, using Hmac SHA-1
                
                Log.d("DH", "Final Key: " + key + "\nSalt: "+salt);
            }
        });
    }
    
    /*
     * Conform to DiffieHellmanProvider interface
     */

    public HttpHost keyExchangeHost(){
        return new HttpHost("http://sample.com",8080);
    }
    public HttpRequest keyExchangeRequest(String ourPublicKey){
    
        // Example request, replace with your implementation
    
        try {
            HttpPost request = new HttpPost();
            request.setURI(new URI("http://sample.com:8080"));
            request.addHeader("Content-Type", "application/json");
            request.addHeader("Accept", "application/json");
            Map<String, Object> map = new HashMap<String, Object>();
            map.put("public_key", ourPublicKey);
            String payload = new JSONObject(map).toString();
            StringEntity params = new StringEntity(payload);
            request.setEntity(params);
            return request;
        }
        catch (Exception e){
            e.printStackTrace();
            return null;
        }
    }
    public String parseKeyExchangeResponse(HttpResponse response){
        
        // Example response parsing, replace with your implementation
        
        try {
            BufferedReader reader = new BufferedReader(new InputStreamReader(response.getEntity().getContent(), "UTF-8"));
            StringBuilder builder = new StringBuilder();
            for (String line = null; (line = reader.readLine()) != null; ) {
                builder.append(line).append("\n");
            }
            JSONTokener tokener = new JSONTokener(builder.toString());
            JSONObject finalResult = new JSONObject(tokener);
            String key = (String)finalResult.get("public_key");
            return key;
        }
        catch (Exception e){
            e.printStackTrace();
            return null;
        }
    }
    public void handleError(GeneralSecurityException e){
        // Handle errors
        e.printStackTrace();
    }
}