rsa.go

/*
RSA私匙和公匙的生成
*/
package main

import (
	"crypto/rand"
	"crypto/rsa"
	"crypto/x509"
	"encoding/gob"
	"encoding/pem"
	"fmt"
	"os"
)

func main() {
	reader := rand.Reader
	bitSize := 512
	privateKey, err := rsa.GenerateKey(reader, bitSize)
	checkError(err)

	fmt.Println("Private key primes", privateKey.Primes[0].String(), privateKey.Primes[1].String())
	fmt.Println("Private key exponent", privateKey.D.String())

	publicKey := privateKey.PublicKey
	fmt.Println("Public key modulus", publicKey.N.String())
	fmt.Println("Public key exponent", publicKey.E)

	saveGobKey("./ca/private.key", privateKey)
	saveGobKey("./ca/public.key", publicKey)

	savePemKey("./ca/private.pem", privateKey)
}

func saveGobKey(fileName string, key interface{}) {
	outFile, err := os.Create(fileName)
	checkError(err)
	encoder := gob.NewEncoder(outFile)
	err = encoder.Encode(key)
	checkError(err)
	outFile.Close()
}

func savePemKey(fileName string, key *rsa.PrivateKey) {
	outFile, err := os.Create(fileName)
	checkError(err)
	var privateKey = &pem.Block{
		Type:    "RSA PRIVATE KEY",
		Headers: nil,
		Bytes:   x509.MarshalPKCS1PrivateKey(key),
	}
	pem.Encode(outFile, privateKey)
	outFile.Close()
}

func checkError(err error) {
	if err != nil {
		fmt.Println("Fatal error ", err.Error())
		os.Exit(1)
	}
}