rsa签名算法c语言,数字签名算法_RSA

public static void jdkRsa(String data) {

try {

// 初始化密钥

KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");

keyPairGenerator.initialize(512);

// 获取密钥

KeyPair keyPair = keyPairGenerator.generateKeyPair();//keypair将公钥和密钥联系起来了，如果不是同一个对象就会验证通不过

RSAPrivateKey rsaPrivateKey = (RSAPrivateKey) keyPair.getPrivate();

PKCS8EncodedKeySpec pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec(rsaPrivateKey.getEncoded());

KeyFactory keyFactory = KeyFactory.getInstance("RSA");

PrivateKey privateKey = keyFactory.generatePrivate(pkcs8EncodedKeySpec);

Signature signature = Signature.getInstance("MD5withRSA");

signature.initSign(privateKey);

signature.update(data.getBytes());

//加密之后的字节数组

byte[] result = signature.sign();

StringBuilder hexString = new StringBuilder();

for (int i = 0; i < result.length; i++) {

if ((result[i] & 0xff) < 0x10)

hexString.append("0");

hexString.append(Integer.toHexString(0xFF & result[i]));

}

System.out.println("加密后的数据：" + hexString.toString().toLowerCase());

//验证是否正确

//获取公钥keyPair一定要和获取私钥的是同一个对象

RSAPublicKey rsaPublicKey=(RSAPublicKey)keyPair.getPublic();

X509EncodedKeySpec x509EncodedKeySpec=new X509EncodedKeySpec(rsaPublicKey.getEncoded());

//keyFactory=keyFactory.getInstance("RSA");

PublicKey publicKey=keyFactory.generatePublic(x509EncodedKeySpec);

//signature=Signature.getInstance("MD5withRSA");

signature.initVerify(publicKey);

signature.update(data.getBytes());

boolean isOk=signature.verify(result);

System.out.println("验证结果："+isOk);

} catch (Exception e) {

e.printStackTrace();

}

}