Convert PEM certificates to PKCS7 bundle (.p7b)

pem-to-p7b.go

package main

import (
	"crypto/x509"
	"encoding/pem"
	"fmt"
	"log"

	"go.mozilla.org/pkcs7"
)

var pemCertificates = ``

func main() {
	p7b, err := pkcs7.NewSignedData(nil)
	if err != nil {
		log.Fatal(err)
	}

	for block, rest := pem.Decode([]byte(pemCertificates)); block != nil; block, rest = pem.Decode(rest) {
		switch block.Type {
		case "CERTIFICATE":
			cert, err := x509.ParseCertificate(block.Bytes)
			if err != nil {
				log.Fatal(err)
			}

			p7b.AddCertificate(cert)
		}
	}

	p7bBytes, err := p7b.Finish()
	if err != nil {
		log.Fatal(err)
	}

	fmt.Println(string(pem.EncodeToMemory(&pem.Block{Type: "PKCS7", Bytes: p7bBytes})))
}