forked from vulcand/vulcand
/
secret.go
107 lines (93 loc) · 2.19 KB
/
secret.go
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package secret
import (
"crypto/rand"
"encoding/hex"
"fmt"
"io"
"github.com/mailgun/vulcand/Godeps/_workspace/src/code.google.com/p/go.crypto/nacl/secretbox"
)
func NewKeyString() (string, error) {
k, err := newKey()
if err != nil {
return "", err
}
return hex.EncodeToString(k), nil
}
func KeyFromString(key string) (*[keyLength]byte, error) {
bytes, err := hex.DecodeString(key)
if err != nil {
return nil, err
}
return decodeKey(bytes)
}
type Box struct {
key *[32]byte
}
type SealedBytes struct {
Val []byte
Nonce []byte
}
func NewBoxFromKeyString(keyS string) (*Box, error) {
key, err := KeyFromString(keyS)
if err != nil {
return nil, err
}
return NewBox(key)
}
func NewBox(bytes *[keyLength]byte) (*Box, error) {
return &Box{key: bytes}, nil
}
func (b *Box) Seal(value []byte) (*SealedBytes, error) {
var nonce [nonceLength]byte
_, err := io.ReadFull(rand.Reader, nonce[:])
if err != nil {
return nil, fmt.Errorf("unable to generate random string: %v", err)
}
var encrypted []byte
encrypted = secretbox.Seal(encrypted[:0], value, &nonce, b.key)
return &SealedBytes{
Val: encrypted,
Nonce: nonce[:],
}, nil
}
func (b *Box) Open(e *SealedBytes) ([]byte, error) {
nonce, err := decodeNonce(e.Nonce)
if err != nil {
return nil, err
}
var decrypted []byte
var ok bool
decrypted, ok = secretbox.Open(decrypted[:0], e.Val, nonce, b.key)
if !ok {
return nil, fmt.Errorf("unable to decrypt message")
}
return decrypted, nil
}
func decodeNonce(bytes []byte) (*[nonceLength]byte, error) {
if len(bytes) != nonceLength {
return nil, fmt.Errorf("wrong nonce length: %d", len(bytes))
}
var nonceBytes [nonceLength]byte
copy(nonceBytes[:], bytes)
return &nonceBytes, nil
}
func decodeKey(bytes []byte) (*[keyLength]byte, error) {
if len(bytes) != keyLength {
return nil, fmt.Errorf("wrong key length: %d", len(bytes))
}
var keyBytes [keyLength]byte
copy(keyBytes[:], bytes)
return &keyBytes, nil
}
func newKey() ([]byte, error) {
var bytes [keyLength]byte
_, err := io.ReadFull(rand.Reader, bytes[:])
if err != nil {
return nil, fmt.Errorf("unable to generate random string: %v", err)
}
return bytes[:], nil
}
const (
nonceLength = 24
keyLength = 32
)