// Copyright 2014 The Go Authors. All rights reserved.

// Use of this source code is governed by a BSD-style

// license that can be found in the LICENSE file.

package internal

import (

	"crypto/rsa"

	"crypto/x509"

	"encoding/pem"

	"errors"

	"fmt"

)

// ParseKey converts the binary contents of a private key file

// to an *rsa.PrivateKey. It detects whether the private key is in a

// PEM container or not. If so, it extracts the the private key

// from PEM container before conversion. It only supports PEM

// containers with no passphrase.

func ParseKey(key []byte) (*rsa.PrivateKey, error) {

	block, _ := pem.Decode(key)

	if block != nil {

		key = block.Bytes

	}

	parsedKey, err := x509.ParsePKCS8PrivateKey(key)

	if err != nil {

		parsedKey, err = x509.ParsePKCS1PrivateKey(key)

		if err != nil {

		}

	}

	parsed, ok := parsedKey.(*rsa.PrivateKey)

	if !ok {

		return nil, errors.New("private key is invalid")

	}

	return parsed, nil

}