rclone/vendor/github.com/youmark/pkcs8/kdf_pbkdf2.go
2019-11-14 21:51:34 +00:00

92 lines
2.2 KiB
Go

package pkcs8
import (
"crypto"
"crypto/sha1"
"crypto/sha256"
"crypto/x509/pkix"
"encoding/asn1"
"errors"
"hash"
"golang.org/x/crypto/pbkdf2"
)
var (
oidPKCS5PBKDF2 = asn1.ObjectIdentifier{1, 2, 840, 113549, 1, 5, 12}
oidHMACWithSHA1 = asn1.ObjectIdentifier{1, 2, 840, 113549, 2, 7}
oidHMACWithSHA256 = asn1.ObjectIdentifier{1, 2, 840, 113549, 2, 9}
)
func init() {
RegisterKDF(oidPKCS5PBKDF2, func() KDFParameters {
return new(pbkdf2Params)
})
}
func newHashFromPRF(ai pkix.AlgorithmIdentifier) (func() hash.Hash, error) {
switch {
case len(ai.Algorithm) == 0 || ai.Algorithm.Equal(oidHMACWithSHA1):
return sha1.New, nil
case ai.Algorithm.Equal(oidHMACWithSHA256):
return sha256.New, nil
default:
return nil, errors.New("pkcs8: unsupported hash function")
}
}
func newPRFParamFromHash(h crypto.Hash) (pkix.AlgorithmIdentifier, error) {
switch h {
case crypto.SHA1:
return pkix.AlgorithmIdentifier{
Algorithm: oidHMACWithSHA1,
Parameters: asn1.RawValue{Tag: asn1.TagNull}}, nil
case crypto.SHA256:
return pkix.AlgorithmIdentifier{
Algorithm: oidHMACWithSHA256,
Parameters: asn1.RawValue{Tag: asn1.TagNull}}, nil
}
return pkix.AlgorithmIdentifier{}, errors.New("pkcs8: unsupported hash function")
}
type pbkdf2Params struct {
Salt []byte
IterationCount int
PRF pkix.AlgorithmIdentifier `asn1:"optional"`
}
func (p pbkdf2Params) DeriveKey(password []byte, size int) (key []byte, err error) {
h, err := newHashFromPRF(p.PRF)
if err != nil {
return nil, err
}
return pbkdf2.Key(password, p.Salt, p.IterationCount, size, h), nil
}
// PBKDF2Opts contains options for the PBKDF2 key derivation function.
type PBKDF2Opts struct {
SaltSize int
IterationCount int
HMACHash crypto.Hash
}
func (p PBKDF2Opts) DeriveKey(password, salt []byte, size int) (
key []byte, params KDFParameters, err error) {
key = pbkdf2.Key(password, salt, p.IterationCount, size, p.HMACHash.New)
prfParam, err := newPRFParamFromHash(p.HMACHash)
if err != nil {
return nil, nil, err
}
params = pbkdf2Params{salt, p.IterationCount, prfParam}
return key, params, nil
}
func (p PBKDF2Opts) GetSaltSize() int {
return p.SaltSize
}
func (p PBKDF2Opts) OID() asn1.ObjectIdentifier {
return oidPKCS5PBKDF2
}