不好意思 加密簽名我都要

私鑰加密得到的密文實(shí)際上就是數(shù)字簽名，要驗(yàn)證這個(gè)簽名是否正確，只能用私鑰持有者的公鑰進(jìn)行解密驗(yàn)證。使用數(shù)字簽名的目的是為了確認(rèn)某個(gè)信息確實(shí)是由某個(gè)發(fā)送方發(fā)送的，任何人都不可能偽造消息，并且，發(fā)送方也不能抵賴

防止抵賴

import javax.crypto.Cipher;
import java.math.BigInteger;
import java.nio.charset.StandardCharsets;
import java.security.*;

/**
 * RSA 公認(rèn)目前最優(yōu)秀的公鑰方案之一
 */
public class RsaEncrypt {
    public static void main(String[] args) throws Exception {
        // 明文:
        byte[] plain = "Hello, encrypt use RSA".getBytes(StandardCharsets.UTF_8);
        // 創(chuàng)建公鑰／私鑰對(duì):
        Partner alice = new Partner("Alice");
        // 用Alice的公鑰加密:
        byte[] pk = alice.getPublicKey();
        System.out.println(String.format("public key: %x", new BigInteger(1, pk)));
        byte[] encrypted = alice.encrypt(plain);
        System.out.println(String.format("encrypted: %x", new BigInteger(1, encrypted)));
        // 用Alice的私鑰解密:
        byte[] sk = alice.getPrivateKey();
        System.out.println(String.format("private key: %x", new BigInteger(1, sk)));
        byte[] decrypted = alice.decrypt(encrypted);
        System.out.println(new String(decrypted, StandardCharsets.UTF_8));
    }

    public static void sha1withRSA() throws GeneralSecurityException {
        // 生成RSA公鑰/私鑰:
        KeyPairGenerator kpGen = KeyPairGenerator.getInstance("RSA");
        kpGen.initialize(1024);
        KeyPair kp = kpGen.generateKeyPair();
        PrivateKey sk = kp.getPrivate();
        PublicKey pk = kp.getPublic();

        // 待簽名的消息:
        byte[] message = "Hello, I am Bob!".getBytes(StandardCharsets.UTF_8);

        // 用私鑰簽名:
        Signature s = Signature.getInstance("SHA1withRSA");
        s.initSign(sk);
        s.update(message);
        byte[] signed = s.sign();
        System.out.println(String.format("signature: %x", new BigInteger(1, signed)));

        // 用公鑰驗(yàn)證:
        Signature v = Signature.getInstance("SHA1withRSA");
        v.initVerify(pk);
        v.update(message);
        boolean valid = v.verify(signed);
        System.out.println("valid? " + valid);
    }
}

class Partner {
    String name;
    // 私鑰:
    PrivateKey sk;
    // 公鑰:
    PublicKey pk;

    public Partner(String name) throws GeneralSecurityException {
        this.name = name;
        // 生成公鑰／私鑰對(duì):
        KeyPairGenerator kpGen = KeyPairGenerator.getInstance("RSA");
        kpGen.initialize(1024);
        KeyPair kp = kpGen.generateKeyPair();
        this.sk = kp.getPrivate();
        this.pk = kp.getPublic();
    }

    // 把私鑰導(dǎo)出為字節(jié)
    public byte[] getPrivateKey() {
        return this.sk.getEncoded();
    }

    // 把公鑰導(dǎo)出為字節(jié)
    public byte[] getPublicKey() {
        return this.pk.getEncoded();
    }

    // 用公鑰加密:
    public byte[] encrypt(byte[] message) throws GeneralSecurityException {
        Cipher cipher = Cipher.getInstance("RSA");
        cipher.init(Cipher.ENCRYPT_MODE, this.pk);
        return cipher.doFinal(message);
    }

    // 用私鑰解密:
    public byte[] decrypt(byte[] input) throws GeneralSecurityException {
        Cipher cipher = Cipher.getInstance("RSA");
        cipher.init(Cipher.DECRYPT_MODE, this.sk);
        return cipher.doFinal(input);
    }
}

我方持有私鑰
我認(rèn)為
調(diào)用方調(diào)用之后 我方可用rsa進(jìn)行簽名加密后
返回調(diào)用方 告知調(diào)用方 調(diào)用方可做進(jìn)一步驗(yàn)證