csr_generate.go

package main

import (
        "os"
        "fmt"

        "crypto/ecdsa"
        "crypto/rand"
        "crypto/elliptic"
        "crypto/x509"
        "crypto/x509/pkix"

        "encoding/pem"
)

func main() {
        if len(os.Args) != 2 {
                panic("Usage: <tool> [hostname]")
        }
        hostname := os.Args[1]

        newkey, err := ecdsa.GenerateKey(elliptic.P384(), rand.Reader)
        if err != nil {
                panic(err)
        }
        subj := pkix.Name {
                CommonName: hostname,
        }
        template := x509.CertificateRequest {
                PublicKey: newkey,
                Subject: subj,
                DNSNames: []string{hostname},
        }
        req, err := x509.CreateCertificateRequest(rand.Reader, &template, newkey)
        if err != nil {
                panic(err)
        }
        privkey, err := x509.MarshalPKCS8PrivateKey(newkey)
        if err != nil {
                panic(err)
        }

        privkeyB := pem.EncodeToMemory(&pem.Block {
                Type: "PRIVATE KEY",
                Bytes: privkey,
        })
        csrB := pem.EncodeToMemory(&pem.Block {
                Type: "CERTIFICATE REQUEST",
                Bytes: req,
        })

        fmt.Println(string(privkeyB))
        fmt.Println(string(csrB))
}