从私钥中提取公钥

1. openssl genrsa -out signing.pem 2048
2. openssl rsa -in signing.pem -outform PEM -pubout -out signing.pub.pem

下面是一个简单的函数,它读取私钥并尝试提取公钥。

谢谢

   func main() {
    priv, err := ioutil.ReadFile("signing.pem")

    block, _ := pem.Decode([]byte(priv))
    if block == nil || block.Type != "RSA PRIVATE KEY" {
        log.Fatal("failed to decode PEM block containing public key")
    }
    key, err := x509.ParsePKCS1PrivateKey(block.Bytes)
    if err != nil {
        log.Fatal(err)
    }

    publicKeyDer := x509.MarshalPKCS1PublicKey(&pub.PublicKey)
    pubKeyBlock := pem.Block{
        Type:    "PUBLIC KEY",
        Headers: nil,
        Bytes:   publicKeyDer,
    }
    pubKeyPem := string(pem.EncodeToMemory(&pubKeyBlock))
    fmt.Println(pubKeyPem)
}

如果有人想查看代码并四处玩,请点击以下链接:

https://play.golang.org/p/rKerkh-31KI