JSON Web Token para Java y Android

<dependency>
    <groupId>io.jsonwebtoken</groupId>
    <artifactId>jjwt-api</artifactId>
    <version>0.10.5</version>
</dependency>
<dependency>
    <groupId>io.jsonwebtoken</groupId>
    <artifactId>jjwt-impl</artifactId>
    <version>0.10.5</version>
    <scope>runtime</scope>
</dependency>
<dependency>
    <groupId>io.jsonwebtoken</groupId>
    <artifactId>jjwt-jackson</artifactId>
    <version>0.10.5</version>
    <scope>runtime</scope>
</dependency>
<!-- Uncomment this next dependency if you want to use RSASSA-PSS (PS256, PS384, PS512) algorithms:
<dependency>
    <groupId>org.bouncycastle</groupId>
    <artifactId>bcprov-jdk15on</artifactId>
    <version>1.60</version>
    <scope>runtime</scope>
</dependency>
-->

dependencies {
    compile 'io.jsonwebtoken:jjwt-api:0.10.5'
    runtime 'io.jsonwebtoken:jjwt-impl:0.10.5',
            // Uncomment the next line if you want to use RSASSA-PSS (PS256, PS384, PS512) algorithms:
            //'org.bouncycastle:bcprov-jdk15on:1.60',
            'io.jsonwebtoken:jjwt-jackson:0.10.5'
}

dependencies {
    api 'io.jsonwebtoken:jjwt-api:0.10.5'
    runtimeOnly 'io.jsonwebtoken:jjwt-impl:0.10.5' 
    runtimeOnly('io.jsonwebtoken:jjwt-orgjson:0.10.5') {
        exclude group: 'org.json', module: 'json' //provided by Android natively
    }
    // Uncomment the next line if you want to use RSASSA-PSS (PS256, PS384, PS512) algorithms:
    //runtimeOnly 'org.bouncycastle:bcprov-jdk15on:1.60'
}

-keepattributes InnerClasses

-keep class io.jsonwebtoken.** { *; }
-keepnames class io.jsonwebtoken.* { *; }
-keepnames interface io.jsonwebtoken.* { *; }

-keep class org.bouncycastle.** { *; }
-keepnames class org.bouncycastle.** { *; }
-dontwarn org.bouncycastle.**

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;

import java.security.Key;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;

import javax.crypto.spec.SecretKeySpec;

import io.jsonwebtoken.Claims;
import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.SignatureAlgorithm;

public class MainActivity extends AppCompatActivity {

    private String SECRET = "DelapatriaelaltonombreengloriosoesplendorconservemosyensusarasdenuevojuremosmMorirantesqueesclavosvivir";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        //Generacion de JSOn Web Token
        String jwt = crearJWT("mouse","JC", "cliente",300000);
        Log.d("JWT", jwt);

        leerJWT(jwt);
    }

    private void leerJWT(String jwt){
        Key key = new SecretKeySpec(SECRET.getBytes(), SignatureAlgorithm.HS512.getJcaName());
        Claims claims = Jwts.parser().setSigningKey(key).parseClaimsJws(jwt).getBody();
        Log.d("JWT", "Subject: " + claims.getSubject());
        Log.d("JWT", "Issuer: " + claims.getIssuer());
        Log.d("JWT", "Level: " + claims.get("lvl"));
        Log.d("JWT", "Exp: " + claims.getExpiration());
    }

    /**
     * @param issuer Proveedor que emitio el JWT
     * @param subject Usuario en nombre del cual fue emitido el JWT
     * @param level Nivel del usuario
     * @param ttlMillis Tiempo de vida del token en milisegundos
     * @return String JWT
     */
    public String crearJWT(String issuer, String subject, String level, long ttlMillis) {

        Key key = new SecretKeySpec(SECRET.getBytes(), SignatureAlgorithm.HS512.getJcaName());

        //Momento de creación del token
        long nowMillis = System.currentTimeMillis();
        Date now = new Date(nowMillis);
        //Tiempo de expiración
        long expMillis = nowMillis + ttlMillis;
        Date exp = new Date(expMillis);

        //header
        Map<String,Object> header = new HashMap();
        header.put("typ", "JWT");

        String jws = Jwts.builder()
                    .setHeaderParams(header)
                    //claim personalizado
                    .claim("lvl",level)
                    //claim standar
                    .setIssuer(issuer)
                    .setSubject(subject)
                    .setExpiration(exp)
                    .setIssuedAt(now)
                     //firma
                    .signWith(key,SignatureAlgorithm.HS512)
                    .compact();
        return jws;
    }
}