Java Last öffentlichen Schlüssel

Question

Ich habe einen öffentlichen Schlüssel zurückgegeben wie

"kty" : "RSA", 
"alg" : "RS256", 
"ext" : false, 
"n": "vswzzDmrqLSHUu61YDxUhM87hjcVjg42NwpFOyLQK8CyW5YRcr1YUkFRNDbb92MTNW3CsSWJX3DSuilnxf8n3_JW-A9R5JAqwmEygYIXuFcoJ_pb923bph0-ayWPBfD-qwYrELvpiEHBf1QSLJYkRb1wzAlwhCeYJorifu2WhCZoOVVYQAEyNqYF7AVhNImioT8-lhFWGqHp2Jt7-oXtCjVVyyShRHUMYyCRzGj1VGI6AU5DgVebXYD2GJawUhX -AD2CzsX8lMXeaVu88sBU9XLL1Zb_cOvAC7wTXxcls0taKx-8PiWUWKjSg0-O2ZXbfFROyQpQYHQH0BkO8XRh8w" 
"e" : "AQAB" 

Und ich möchte Java verwenden, um es zu laden, und mein Code wie

package key; 

import java.security.KeyFactory; 
import java.security.PublicKey; 
import java.security.spec.X509EncodedKeySpec; 
import java.util.Base64; 

public class PublicKeyReader { 

    public static PublicKey get() throws Exception { 
     String key = "vswzzDmrqLSHUu61YDxUhM87hjcVjg42NwpFOyLQK8CyW5YRcr1YUkFRNDbb92MTNW3CsSWJX3DSuilnxf8n3_JW-A9R5JAqwmEygYIXuFcoJ_pb923bph0-ayWPBfD-qwYrELvpiEHBf1QSLJYkRb1wzAlwhCeYJorifu2WhCZoOVVYQAEyNqYF7AVhNImioT8-lhFWGqHp2Jt7-oXtCjVVyyShRHUMYyCRzGj1VGI6AU5DgVebXYD2GJawUhX-AD2CzsX8lMXeaVu88sBU9XLL1Zb_cOvAC7wTXxcls0taKx-8PiWUWKjSg0-O2ZXbfFROyQpQYHQH0BkO8XRh8w"; 

     X509EncodedKeySpec spec = new X509EncodedKeySpec(key.getBytes()); 
     KeyFactory kf = KeyFactory.getInstance("RSA"); 
     return kf.generatePublic(spec); 
    } 

    public static void main(String[] args) { 
     try { 
      new PublicKeyReader().get(); 
     } catch (Exception e) { 
      e.printStackTrace(); 
     } 

    } 
} 

und ich habe Ausnahme geworfen, sagt java.security.spec.InvalidKeySpecException: java.security.InvalidKeyException: invalid key format

Wie man es richtig lädt?

Answer 1

Java nur Ansatz (Look ma, keine Bibliotheken):

package nl.owlstead.stackoverflow; 

import java.io.File; 
import java.math.BigInteger; 
import java.nio.file.Files; 
import java.security.KeyFactory; 
import java.security.PublicKey; 
import java.security.interfaces.RSAPublicKey; 
import java.security.spec.RSAPublicKeySpec; 
import java.util.Base64; 
import java.util.Base64.Decoder; 
import java.util.List; 
import java.util.regex.Matcher; 
import java.util.regex.Pattern; 

public class LoadRSAKeyFromText { 

    public static void main(String[] args) throws Exception { 
     // parse the lines to find the modulus n and public exponent e 
     List<String> all = Files.readAllLines(new File(args[0]).toPath()); 
     String nString = null, eString = null; 
     for (String line : all) { 
      Pattern nPattern = Pattern.compile("\"n\"\\s*:\\s*\"(.*?)\",?"); 
      Matcher nMatcher = nPattern.matcher(line); 
      if (nMatcher.matches()) { 
       nString = nMatcher.group(1).replaceAll("\\s+", ""); 
      } 

      Pattern ePattern = Pattern.compile("\"e\"\\s*:\\s*\"(.*?)\",?"); 
      Matcher eMatcher = ePattern.matcher(line); 
      if (eMatcher.matches()) { 
       eString = eMatcher.group(1); 
      } 
     } 

     // decode base 64 (with _ and -, so URL safe) 
     Decoder urlDecoder = Base64.getUrlDecoder(); 
     byte[] nData = urlDecoder.decode(nString); 
     byte[] eData = urlDecoder.decode(eString); 

     // convert to *positive* integers 
     BigInteger n = new BigInteger(1, nData); 
     BigInteger e = new BigInteger(1, eData); 

     // create RSA specification and convert to key 
     RSAPublicKeySpec keySpec = new RSAPublicKeySpec(n, e); 
     KeyFactory kf = KeyFactory.getInstance("RSA"); 
     RSAPublicKey pk = (RSAPublicKey) kf.generatePublic(keySpec); 
     System.out.println(pk.getAlgorithm()); 
    } 
} 

Java nicht weiß, diese Art von Format, so dass Sie es selbst zu analysieren haben, oder einen Decoder zu finden. Ich war faul und programmierte es.