1、甲方构建密钥对(公钥和私钥,公钥给对方,私钥留给自己)
2、甲方使用私钥加密数据,然后用私钥对加密后的数据签名,并把这些发送给乙方;乙方使用公钥、签名来验证待解密数据是否有效,如果有效使用公钥对数据解密。
3、乙方使用公钥加密数据,向甲方发送经过加密后的数据;甲方获得加密数据,通过私钥解密。
package com.rsa.core; import java.security.Key; import java.security.KeyFactory; import java.security.KeyPair; import java.security.KeyPairGenerator; import java.security.PrivateKey; import java.security.PublicKey; import java.security.interfaces.RSAPrivateKey; import java.security.interfaces.RSAPublicKey; import java.security.spec.PKCS8EncodedKeySpec; import java.security.spec.X509EncodedKeySpec; import javax.crypto.Cipher; import sun.misc.BASE64Decoder; import sun.misc.BASE64Encoder; public class RSACoder { public static PublicKey getPublicKey(String key) throws Exception { byte[] keyBytes; keyBytes = (new BASE64Decoder()).decodeBuffer(key); X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes); KeyFactory keyFactory = KeyFactory.getInstance("RSA"); PublicKey publicKey = keyFactory.generatePublic(keySpec); return publicKey; } public static PrivateKey getPrivateKey(String key) throws Exception { byte[] keyBytes; keyBytes = (new BASE64Decoder()).decodeBuffer(key); PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(keyBytes); KeyFactory keyFactory = KeyFactory.getInstance("RSA"); PrivateKey privateKey = keyFactory.generatePrivate(keySpec); return privateKey; } /** * 得到密钥字符串(经过base64编码) * @return */ public static String getKeyString(Key key) throws Exception { byte[] keyBytes = key.getEncoded(); String s = (new BASE64Encoder()).encode(keyBytes); return s; } public static void main(String[] args) throws Exception { KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance("RSA"); //密钥位数 keyPairGen.initialize(1024); //密钥对 KeyPair keyPair = keyPairGen.generateKeyPair(); // 公钥 PublicKey publicKey = (RSAPublicKey) keyPair.getPublic(); // 私钥 PrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate(); String publicKeyString = getKeyString(publicKey); System.out.println("public:\n" + publicKeyString); String privateKeyString = getKeyString(privateKey); System.out.println("private:\n" + privateKeyString); //加解密类 Cipher cipher = Cipher.getInstance("RSA");//Cipher.getInstance("RSA/ECB/PKCS1Padding"); //明文 byte[] plainText = "91686280721609".getBytes(); //加密 cipher.init(Cipher.ENCRYPT_MODE, publicKey); byte[] enBytes = cipher.doFinal(plainText); String s1 = new String(enBytes); System.out.println("加密后的密文:" + s1); //通过密钥字符串得到密钥 publicKey = getPublicKey(publicKeyString); privateKey = getPrivateKey(privateKeyString); //解密 cipher.init(Cipher.DECRYPT_MODE, privateKey); byte[]deBytes = cipher.doFinal(enBytes); publicKeyString = getKeyString(publicKey); System.out.println("public:\n" +publicKeyString); privateKeyString = getKeyString(privateKey); System.out.println("private:\n" + privateKeyString); String s = new String(deBytes); System.out.println(s); } }