将 rsa 私钥分成两半

Question

我想把rsa私钥分成两半分别存放在两个不同的地方，怎么办？

public GenerateKeys(int keylength) throws NoSuchAlgorithmException, NoSuchProviderException {
    keylength=512;
    this.keyGen = KeyPairGenerator.getInstance("RSA");
    SecureRandom random = SecureRandom.getInstance("SHA1PRNG");
    this.keyGen.initialize(keylength, random);
}

Answer 1

这是一个示例，它将您的私钥分成两部分，D1 和 D2。类似于讨论 here

import java.security.KeyPair;
import java.security.KeyFactory;
import java.security.KeyPairGenerator;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.security.spec.EncodedKeySpec;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;

public class OnetimePad{

    public static byte[] xor(byte[] key, byte[] rand){
        if(key.length != rand.length){
            return null;
        }
        byte[] ret = new byte[key.length];
        for(int i =0; i < key.length; i++){
            ret[i] = (byte)((key[i] ^ rand[i]) );
        }

        return ret;
    }

     public static void main(String []args) throws Exception{
        SecureRandom random = new SecureRandom();  


        KeyPairGenerator keyGen = KeyPairGenerator.getInstance("RSA");
        keyGen.initialize(1024);
        KeyPair keypair = keyGen.genKeyPair();
        PrivateKey privateKey = keypair.getPrivate();  
        byte[] privateKeyBytes = privateKey.getEncoded();

        //Private Key Part 1
        byte[] D1 = new byte[privateKeyBytes.length];
        random.nextBytes(D1);

        //Private Key Part 2
        byte[] D2 = xor(privateKeyBytes, D1);

        //now D1 and D2 are split parts of private keys..

        //Let's verify if we could reproduce them back 
        byte[] privateKeyByesTmp = xor(D2, D1);
        KeyFactory keyFactory = KeyFactory.getInstance("RSA");
        EncodedKeySpec privateKeySpec = new PKCS8EncodedKeySpec(privateKeyByesTmp);
        PrivateKey privateKey2 = keyFactory.generatePrivate(privateKeySpec);
        boolean same = privateKey.equals(privateKey2); 
        if(same){
            System.out.println("Key loaded successfully");
        }else{
            System.out.println("Ooops");
        }

     }
}

注：请在 random seed 上查看 SecureRandom 的以下文档。特别是突出显示的部分

Many SecureRandom implementations are in the form of a pseudo-random number generator (PRNG), which means they use a deterministic algorithm to produce a pseudo-random sequence from a true random seed. Other implementations may produce true random numbers, and yet others may use a combination of both techniques.

将 rsa 私钥分成两半

divide rsa private key in two halves

java

rsa

key