generate stir/shaken csr ATIS-1000080

csr.go

package main

import (
    "encoding/asn1"
    "crypto/elliptic"
    "crypto/ecdsa"
    "crypto/rand"
    "crypto/x509"
    "crypto/x509/pkix"
    "encoding/pem"
    "os"
)

func encodeTNAuthList(spc string) []byte {
    str, _ := asn1.Marshal(asn1.RawValue {
        Class: 0,
        IsCompound: false,
        Tag: asn1.TagIA5String,
        Bytes: []byte(spc),
    })
    av := asn1.RawValue {
        Class: 2,
        IsCompound: true,
        Tag: 0,
        Bytes: str,
    }
    avo, _ := asn1.Marshal(av)
    a0 := asn1.RawValue {
        Class: 0,
        IsCompound: true,
        Tag: asn1.TagSequence,
        Bytes: avo,
    }
    by, _ := asn1.Marshal(a0)
    return by
}

func main() {
    ecKey, err := ecdsa.GenerateKey(elliptic.P256(), rand.Reader)

    template := x509.CertificateRequest{
        Subject: pkix.Name {
            Country:      []string {"US"},
            Province:     []string {"VA"},
            Locality:     []string {"la"},
            Organization: []string {"telecom ltd"},
            OrganizationalUnit: []string {"VOIP"},
        },
        SignatureAlgorithm: x509.ECDSAWithSHA256,
        ExtraExtensions: []pkix.Extension{
            pkix.Extension{
                Id:[]int{1,3,6,1,5,5,7,1,26},
                Value:encodeTNAuthList("1234"),
            },
        },
    }

    csrBytes, err := x509.CreateCertificateRequest(rand.Reader, &template, ecKey)
    if err != nil {
        panic(err)
    }
    pem.Encode(os.Stdout, &pem.Block{Type: "CERTIFICATE REQUEST", Bytes: csrBytes})
}