pkcs8格式证书转换pkcs1格式

package main

import (
	"encoding/base64"
	"fmt"
	"os"
	"os/exec"
	"strings"
	"time"

	l_file "github.com/lixu-any/go-tools/file"
)

//pkcs8格式，所以需要转为pkcs1格式，命令=>openssl rsa -in pks8.pem -out pks1.pem
//这里的私钥处理方式 1.以-----BEGIN RSA PRIVATE KEY----- +"换行" +原生字符串64位换行 +"换行" +-----END RSA PRIVATE KEY-----
//2.由于原生秘钥是pkcs8格式，所以需要转为pkcs1格式，命令=>openssl rsa -in pks8.pem -out pks1.pem
//3.openssl 下载地址 https://slproweb.com/products/Win32OpenSSL.html

func WriteToFile(fileName string, content string) error {
	f, err := os.OpenFile(fileName, os.O_WRONLY|os.O_TRUNC|os.O_CREATE, 0644)
	if err != nil {
		fmt.Println("file create failed. err: " + err.Error())
	} else {
		// offset
		//os.Truncate(filename, 0) //clear
		n, _ := f.Seek(0, os.SEEK_END)
		_, err = f.WriteAt([]byte(content), n)
		fmt.Println("write succeed!")
		defer f.Close()
	}
	return err
}

const (
	KEY_BEGIN = "-----BEGIN RSA PRIVATE KEY-----"
	KEY_END   = "-----END RSA PRIVATE KEY-----"
)

func main() {

	var (
		pemstr  string
		nowtime = int32(time.Now().Unix())
		bt      = fmt.Sprintf("1_%d.pem", nowtime)
		wt      = fmt.Sprintf("2_%d.pem", nowtime)
		pt      = fmt.Sprintf("private_%d.txt", nowtime)
	)

	args := os.Args
	if len(args) < 2 {
		fmt.Println("params error")
		return
	}

	pemstr = args[1]
	fomartpem := ""

	parr := strings.Split(pemstr, "")

	for k, v := range parr {
		if k != 0 && k%64 == 0 {
			fomartpem += "\n"
		}
		fomartpem += v
	}

	fomartpem = KEY_BEGIN + "\n" + fomartpem
	fomartpem = fomartpem + "\n" + KEY_END

	os.Create(bt)

	l_file.WriteTxt(bt, fomartpem)

	// command := exec.Command("openssl", "rsa", "-in", "/Users/lixu/code/git/tools/"+bt, "-out", "/Users/lixu/code/git/tools/"+wt, ">mmn.txt")

	cmd := fmt.Sprintf("openssl rsa -in %s -out %s", bt, wt)

	c := exec.Command("bash", "-c", cmd)
	// 此处是windows版本
	// c := exec.Command("cmd", "/C", cmd)
	output, _ := c.CombinedOutput()

	fmt.Println(string(output))

	sbt, _ := l_file.ReadFile(wt)

	signstr := base64.StdEncoding.EncodeToString(sbt)

	fmt.Println(signstr)

	os.Create(pt)

	l_file.WriteTxt(pt, signstr)

}

openssl rsa -in pks8.pem -out pks1.pem