Golang X509证书如何封送目标信息扩展

package main

import (
    "crypto/rand"
    "crypto/rsa"
    "crypto/x509"
    "crypto/x509/pkix"
    "encoding/pem"
    "fmt"
    "math/big"
    "os"
    "time"
)

func main() {
    // 创建一个X509证书对象
    cert := &x509.Certificate{
        SerialNumber: big.NewInt(1234),
        Subject: pkix.Name{
            CommonName:   "example.com",
            Organization: []string{"Example Organization"},
        },
        NotBefore:             time.Now(),
        NotAfter:              time.Now().Add(365 * 24 * time.Hour),
        BasicConstraintsValid: true,
        IsCA:                  true,
    }

    // 创建目标信息扩展字段
    targetExtension := pkix.Extension{
        Id:       []int{1, 2, 3, 4}, // 自定义的OID
        Value:    []byte("target information"),
        Critical: false,
    }

    // 将目标信息扩展字段添加到证书对象中
    cert.ExtraExtensions = append(cert.ExtraExtensions, targetExtension)

    // 生成RSA私钥
    privateKey, err := rsa.GenerateKey(rand.Reader, 2048)
    if err != nil {
        fmt.Println("Failed to generate private key:", err)
        return
    }

    // 生成证书
    derBytes, err := x509.CreateCertificate(rand.Reader, cert, cert, &privateKey.PublicKey, privateKey)
    if err != nil {
        fmt.Println("Failed to create certificate:", err)
        return
    }

    // 将证书保存到文件
    certFile, err := os.Create("certificate.crt")
    if err != nil {
        fmt.Println("Failed to create certificate file:", err)
        return
    }
    defer certFile.Close()

    pem.Encode(certFile, &pem.Block{Type: "CERTIFICATE", Bytes: derBytes})

    fmt.Println("Certificate generated successfully.")
}