RSA加密与密钥和指数在android中

Question

我有一个私钥和指数，我需要在android应用程序中实现字符串的RSA加密。 我该怎么做？有没有RSA加密的默认类？

Answer 1

public void saveToFile(String fileName, BigInteger mod, BigInteger exp) 
     throws IOException { 
    ObjectOutputStream oout = new ObjectOutputStream(
      new BufferedOutputStream(new FileOutputStream(fileName))); 
    try { 
     oout.writeObject(mod); 
     oout.writeObject(exp); 
    } catch (Exception e) { 
     throw new IOException("Unexpected error", e); 
    } finally { 
     oout.close(); 
    } 
} 

PublicKey ReadPublicKeyFromFile(String keyFileName) throws IOException { 
    InputStream in = RSACrypt.class.getClassLoader().getResourceAsStream(keyFileName); 
    ObjectInputStream oin = new ObjectInputStream(new BufferedInputStream(
      in)); 
    try { 
     BigInteger m = (BigInteger) oin.readObject(); 
     BigInteger e = (BigInteger) oin.readObject(); 
     RSAPublicKeySpec keySpec = new RSAPublicKeySpec(m, e); 
     KeyFactory fact = KeyFactory.getInstance("RSA"); 
     PublicKey pubKey = fact.generatePublic(keySpec); 
     return pubKey; 
    } catch (Exception e) { 
     throw new RuntimeException("Spurious serialisation error", e); 
    } finally { 
     oin.close(); 
    } 
} 

从http://www.developpez.net/forums/d1001867/java/developpement-web-java/besoin-daide-rsa/