1// Copyright 2015 The Go Authors. All rights reserved.
 2// Use of this source code is governed by a BSD-style
 3// license that can be found in the LICENSE file.
 4
 5package pkcs12
 6
 7import (
 8	"crypto/hmac"
 9	"crypto/sha1"
10	"crypto/x509/pkix"
11	"encoding/asn1"
12)
13
14type macData struct {
15	Mac        digestInfo
16	MacSalt    []byte
17	Iterations int `asn1:"optional,default:1"`
18}
19
20// from PKCS#7:
21type digestInfo struct {
22	Algorithm pkix.AlgorithmIdentifier
23	Digest    []byte
24}
25
26var (
27	oidSHA1 = asn1.ObjectIdentifier([]int{1, 3, 14, 3, 2, 26})
28)
29
30func verifyMac(macData *macData, message, password []byte) error {
31	if !macData.Mac.Algorithm.Algorithm.Equal(oidSHA1) {
32		return NotImplementedError("unknown digest algorithm: " + macData.Mac.Algorithm.Algorithm.String())
33	}
34
35	key := pbkdf(sha1Sum, 20, 64, macData.MacSalt, password, macData.Iterations, 3, 20)
36
37	mac := hmac.New(sha1.New, key)
38	mac.Write(message)
39	expectedMAC := mac.Sum(nil)
40
41	if !hmac.Equal(macData.Mac.Digest, expectedMAC) {
42		return ErrIncorrectPassword
43	}
44	return nil
45}