本文实例讲述了Java编程实现非对称加密的方法。分享给大家供大家参考，具体如下：
对称加密算法在加密和解密时使用的是同一个秘钥；而非对称加密算法需要两个密钥来进行加密和解密，这两个秘钥是公开密钥（public key，简称公钥）和私有密钥（private key，简称私钥）。
是一种 高级的双保险加密方式，一般的实现加密方式有DH密钥交换算法，RSA基于因子分解算法，ElGamal离散对数算法及ECC椭圆曲线加密等。
DH加密解密
public class EncryptDH {
private static String dhStr = "encrypt test by DH";
public static void main(String[] args) {
jdkDh();
}
private static void jdkDh() {
try {
// 初始化发送方密钥
KeyPairGenerator senderKeyPairGenerator = KeyPairGenerator.getInstance("DH");
senderKeyPairGenerator.initialize(512);
KeyPair senderKeyPair = senderKeyPairGenerator.generateKeyPair();
byte[] senderPublicKeyEnc = senderKeyPair.getPublic().getEncoded();// 发送方的公钥，发送给接受方，发送方式多种，比如文件，网络等
// 初始化接受方密钥
KeyFactory receiverKeyFactory = KeyFactory.getInstance("DH");
X509EncodedKeySpec x509EncodedKeySpec = new X509EncodedKeySpec(senderPublicKeyEnc);
PublicKey receiverPublicKey = receiverKeyFactory.generatePublic(x509EncodedKeySpec);
DHParameterSpec dhParameterSpec = ((DHPublicKey) receiverPublicKey).getParams();
KeyPairGenerator receiverKeyPairGenerator = KeyPairGenerator.getInstance("DH");
receiverKeyPairGenerator.initialize(dhParameterSpec);
KeyPair receiveKeyPair = receiverKeyPairGenerator.generateKeyPair();
PrivateKey receiverPrivateKey = receiveKeyPair.getPrivate();
byte[] receiverPublicKeyEnc = receiveKeyPair.getPublic().getEncoded();
// 密钥构建
KeyAgreement receiverKeyAgreement = KeyAgreement.getInstance("DH");
receiverKeyAgreement.init(receiverPrivateKey);
receiverKeyAgreement.doPhase(receiverPublicKey, true);
SecretKey receiverSecretKey = receiverKeyAgreement.generateSecret("DES");
KeyFactory senderKeyFactory = KeyFactory.getInstance("DH");
x509EncodedKeySpec = new X509EncodedKeySpec(receiverPublicKeyEnc);
PublicKey senderPublicKey = senderKeyFactory.generatePublic(x509EncodedKeySpec);
KeyAgreement senderKeyAgreement = KeyAgreement.getInstance("DH");
senderKeyAgreement.init(senderKeyPair.getPrivate());
senderKeyAgreement.doPhase(senderPublicKey, true);
SecretKey snederSecretKey = senderKeyAgreement.generateSecret("DES");
if (Objects.equals(receiverSecretKey, snederSecretKey)) {
System.out.println("双方密钥相同");
}
// 加密
Cipher cipher = Cipher.getInstance("DES");
cipher.init(Cipher.ENCRYPT_MODE, snederSecretKey);
byte[] result = cipher.doFinal(dhStr.getBytes());
System.out.println("DH加密后为：" + base64.encode(result));
// 解密
cipher.init(Cipher.DECRYPT_MODE, receiverSecretKey);
result = cipher.doFinal(result);
System.out.println("DH解密后为：" + new String(result));
}
catch (Exception e) {
e.printStackTrace();
}
}
}
RSA加密解密
public class EncryptRSA {
private static String rsaStr = "encrypt test by ElGamal";
public static void main(String[] args) {
jdkRSA();
}
private static void jdkRSA() {
try {
// 初始化密钥
KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
keyPairGenerator.initialize(512);
KeyPair keyPair = keyPairGenerator.generateKeyPair();
RSAPublicKey rsaPublicKey = (RSAPublicKey) keyPair.getPublic();
RSAPrivateKey rsaPrivateKey = (RSAPrivateKey) keyPair.getPrivate();
System.out.println("RSA公钥：" + base64.encode(rsaPublicKey.getEncoded()));
System.out.println("RSA私钥：" + base64.encode(rsaPrivateKey.getEncoded()));
// 私钥加密，公钥解密--加密
PKCS8EncodedKeySpec pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec(rsaPrivateKey.getEncoded());
KeyFactory keyFactory = KeyFactory.getInstance("RSA");
PrivateKey privateKey = keyFactory.generatePrivate(pkcs8EncodedKeySpec);
Cipher cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.ENCRYPT_MODE, privateKey);
byte[] result = cipher.doFinal(rsaStr.getBytes());
System.out.println("RSA私钥加密，公钥解密--加密：" + base64.encode(result));
// 私钥加密，公钥解密--解密
X509EncodedKeySpec x509EncodedKeySpec = new X509EncodedKeySpec(rsaPublicKey.getEncoded());
keyFactory = KeyFactory.getInstance("RSA");
PublicKey publicKey = keyFactory.generatePublic(x509EncodedKeySpec);
cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.DECRYPT_MODE, publicKey);
result = cipher.doFinal(result);
System.out.println("RSA私钥加密，公钥解密--解密：" + new String(result));
// 公钥加密，私钥解密--加密
x509EncodedKeySpec = new X509EncodedKeySpec(rsaPublicKey.getEncoded());
keyFactory = KeyFactory.getInstance("RSA");
publicKey = keyFactory.generatePublic(x509EncodedKeySpec);
cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.ENCRYPT_MODE, publicKey);
result = cipher.doFinal(rsaStr.getBytes());
System.out.println("公钥加密，私钥解密--加密：" + base64.encode(result));
// 公钥加密，私钥解密--解密
pkcs8EncodedKeySpec=new PKCS8EncodedKeySpec(rsaPrivateKey.getEncoded());
keyFactory = KeyFactory.getInstance("RSA");
privateKey= keyFactory.generatePrivate(pkcs8EncodedKeySpec);
cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.DECRYPT_MODE, privateKey);
result = cipher.doFinal(result);
System.out.println("公钥加密，私钥解密--解密：" + new String(result));
}
catch (Exception e) {
e.printStackTrace();
}
}
}
ElGamal加密
public class EncrypElGamal {
private static String rsaStr = "encrypt test by ElGamal";
public static void main(String[] args) {
jdkRSA();
}
private static void jdkRSA() {
try {
// 公钥加密，私钥解密
// Security.addProvider(new BouncyCastleProvider());//需要添加bouncycastleprovider jar
//初始化密钥
AlgorithmParameterGenerator algorithmParameterGenerator=AlgorithmParameterGenerator.getInstance("ElGamal");
algorithmParameterGenerator.init(256);
AlgorithmParameters algorithmParameters=algorithmParameterGenerator.generateParameters();
DHParameterSpec dhParameterSpec=algorithmParameters.getParameterSpec(DHParameterSpec.class);
KeyPairGenerator keyPairGenerator=KeyPairGenerator.getInstance("ElGamal");
keyPairGenerator.initialize(dhParameterSpec,new SecureRandom());
KeyPair keyPair=keyPairGenerator.generateKeyPair();
PublicKey publicKey=keyPair.getPublic();
PrivateKey privateKey=keyPair.getPrivate();
System.out.println("ElGamal加密公钥："+base64.encode(publicKey.getEncoded()));
System.out.println("ElGamal加密私钥："+base64.encode(privateKey.getEncoded()));
//加密解密同Rsa是一样的
}
catch (Exception e) {
e.printStackTrace();
}
}
}
Ecc加密可以参考：http://www.pediy.com/kssd/pediy06/pediy6014.htm等。
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http://tools.jb51.net/password/sha_encode
更多关于java相关内容感兴趣的读者可查看本站专题：《Java数学运算技巧总结》、《Java数据结构与算法教程》、《Java字符与字符串操作技巧总结》、《java日期与时间操作技巧汇总》、《Java操作DOM节点技巧总结》和《Java缓存操作技巧汇总》
希望本文所述对大家java程序设计有所帮助。
