Así que actualmente estoy trabajando en una implementación deKraken API paraJava. Estoy usando este código de muestra que encontré enhttp://pastebin.com/nHJDAbH8.

El uso general según lo descrito porKraken (https://www.kraken.com/help/api) es:

API-Key = Clave API

API-Sign = Firma del mensaje usando HMAC-SHA512 de
( URI path + SHA256( nonce + POST data ) ) ybase64 clave API API decodificada

y

nonce = siempre aumentando el entero de 64 bits sin signo
otp = contraseña de dos factores (si está habilitado para dos factores, de lo contrario no es necesario)

Sin embargo, me enfrento a la siguiente respuesta:

{"error":["EAPI:Invalid key"]}

Ya probé un par de maneras (obteniendo una nueva API, tratando de cambiar elsha256 métodos, porque pensé que algo anda mal con la forma en que se hace el hash)

Entonces este es el código:

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.UnsupportedEncodingException;
import java.net.HttpURLConnection;
import java.net.URL;
import java.security.InvalidKeyException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;

import org.apache.commons.codec.binary.Base64;

public class KrakenClient {

        protected static String key = "myAPIKey";     // API key
        protected static String secret = "MySecret====";  // API secret
        protected static String url = "api.kraken.com";     // API base URL
        protected static String version = "0"; // API version


        public static void main(String[] args) throws Exception {
                queryPrivateMethod("Balance");
        }

        public static void queryPrivateMethod(String method) throws NoSuchAlgorithmException, IOException{

                long nonce = System.currentTimeMillis();

                String path = "/" + version + "/private/" + method; // The path like "/0/private/Balance"

                String urlComp = "https://"+url+path; // The complete url like "https://api.kraken.com/0/private/Balance"

                String postdata = "nonce="+nonce;

                String sign = createSignature(nonce, path, postdata);

                postConnection(urlComp, sign, postdata);
        }

        /**
         * @param nonce
         * @param path
         * @param postdata
         * @return
         * @throws NoSuchAlgorithmException
         * @throws IOException
         */
        private static String createSignature(long nonce, String path,
                        String postdata) throws NoSuchAlgorithmException, IOException {

                return hmac(path+sha256(nonce + postdata),  new String(Base64.decodeBase64(secret)));
        }

        public static String sha256Hex(String text) throws NoSuchAlgorithmException, IOException{
                return org.apache.commons.codec.digest.DigestUtils.sha256Hex(text);
        }

        public static byte[] sha256(String text) throws NoSuchAlgorithmException, UnsupportedEncodingException{
                MessageDigest md = MessageDigest.getInstance("SHA-256");

                md.update(text.getBytes());
                byte[] digest = md.digest();

                return digest;
        }

        public static void postConnection(String url1, String sign, String postData) throws IOException{

                URL url = new URL( url1 );
                HttpURLConnection connection = (HttpURLConnection) url.openConnection();

                connection.addRequestProperty("API-Key", key);
                connection.addRequestProperty("API-Sign", Base64.encodeBase64String(sign.getBytes()));
                //              connection.addRequestProperty("API-Sign", sign);
                connection.addRequestProperty("User-Agent", "Mozilla/4.0");
                connection.setRequestMethod( "POST" );
                connection.setDoInput( true );
                connection.setDoOutput( true );
                connection.setUseCaches( false );
                //              connection.setRequestProperty( "Content-Type",
                //                              "application/x-www-form-urlencoded" );
                connection.setRequestProperty( "Content-Length", String.valueOf(postData.length()) );

                OutputStreamWriter writer = new OutputStreamWriter( connection.getOutputStream() );
                writer.write( postData );
                writer.flush();


                BufferedReader reader = new BufferedReader(
                                new InputStreamReader(connection.getInputStream()) );

                for ( String line; (line = reader.readLine()) != null; )
                {
                        System.out.println( line );
                }

                writer.close();
                reader.close();
        }


        public static String hmac(String text, String secret){

                Mac mac =null;
                SecretKeySpec key = null;

                // Create a new secret key
                try {
                        key = new SecretKeySpec( secret.getBytes( "UTF-8"), "HmacSHA512" );
                } catch( UnsupportedEncodingException uee) {
                        System.err.println( "Unsupported encoding exception: " + uee.toString());
                        return null;
                }
                // Create a new mac
                try {
                        mac = Mac.getInstance( "HmacSHA512" );
                } catch( NoSuchAlgorithmException nsae) {
                        System.err.println( "No such algorithm exception: " + nsae.toString());
                        return null;
                }

                // Init mac with key.
                try {
                        mac.init( key);
                } catch( InvalidKeyException ike) {
                        System.err.println( "Invalid key exception: " + ike.toString());
                        return null;
                }


                // Encode the text with the secret
                try {

                        return new String( mac.doFinal(text.getBytes( "UTF-8")));
                } catch( UnsupportedEncodingException uee) {
                        System.err.println( "Unsupported encoding exception: " + uee.toString());
                        return null;
                }
        }
}