package rsa

import (
	"crypto"
	"crypto/rsa"
	"encoding/base64"
	"log"
)

func main() {
	// 1、对base64编码的签名内容进行解码，返回签名字节
	a := "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCbtzmEy7zEUDsskOHI8TFGBG/slgXIvzzO7bcejLyEiSMbTtZMNgGFewpYGaAb1fCMTUuc5HQrKx4T/qr2C2nkw0WjroE5UrykYag6qgpx2WXc68+cn0mODgaeczWnt0gjCqRn+lE1O9wxPbJwL85ZH58cWFjha1AMedeh5lg9iQIDAQAB"
	bytes, err := base64.StdEncoding.DecodeString(a)
	if err != nil {
		log.Fatal(err)
	}
	// 2、选择hash算法，对需要签名的数据进行hash运算
	myhash := crypto.SHA256
	hashInstance := myhash.New()
	hashInstance.Write(data)
	hashed := hashInstance.Sum(nil)
	// 3、读取公钥文件，解析出公钥对象
	publicKey, err := ReadParsePublicKey(filename)
	if err != nil {
		return err
	}
	// 4、RSA验证数字签名（参数是公钥对象、哈希类型、签名文件的哈希串、签名后的字节）
	return rsa.VerifyPKCS1v15(publicKey, myhash, hashed, bytes)
}