108 lines
2.7 KiB
Go
108 lines
2.7 KiB
Go
|
// Copyright (C) 2018 Storj Labs, Inc.
|
||
|
|
// See LICENSE for copying information.
|
||
|
|
|
||
|
|
package paths
|
||
|
|
|
||
|
|
import (
|
||
|
|
"crypto/aes"
|
||
|
|
"crypto/cipher"
|
||
|
|
"crypto/hmac"
|
||
|
|
"crypto/sha512"
|
||
|
|
"encoding/base64"
|
||
|
|
)
|
||
|
|
|
||
|
|
// Encrypt the given path with the given key
|
||
|
|
func Encrypt(path []string, key []byte) (encryptedPath []string, err error) {
|
||
|
|
encryptedPath = make([]string, len(path))
|
||
|
|
for i, seg := range path {
|
||
|
|
encryptedPath[i], err = encrypt(seg, key)
|
||
|
|
if err != nil {
|
||
|
|
return nil, err
|
||
|
|
}
|
||
|
|
key = deriveSecret(key, seg)
|
||
|
|
}
|
||
|
|
return encryptedPath, nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// Decrypt the given encrypted path with the given key
|
||
|
|
func Decrypt(encryptedPath []string, key []byte) (path []string, err error) {
|
||
|
|
path = make([]string, len(encryptedPath))
|
||
|
|
for i, seg := range encryptedPath {
|
||
|
|
path[i], err = decrypt(seg, key)
|
||
|
|
if err != nil {
|
||
|
|
return nil, err
|
||
|
|
}
|
||
|
|
key = deriveSecret(key, path[i])
|
||
|
|
}
|
||
|
|
return path, nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// DeriveKey derives the key for the given path from the given root key
|
||
|
|
func DeriveKey(key []byte, path []string) (derivedKey []byte) {
|
||
|
|
derivedKey = key
|
||
|
|
for _, seg := range path {
|
||
|
|
derivedKey = deriveSecret(derivedKey, seg)
|
||
|
|
}
|
||
|
|
return derivedKey
|
||
|
|
}
|
||
|
|
|
||
|
|
func encrypt(text string, secret []byte) (cipherText string, err error) {
|
||
|
|
key, nonce := getAESGCMKeyAndNonce(secret)
|
||
|
|
block, err := aes.NewCipher(key)
|
||
|
|
if err != nil {
|
||
|
|
return "", Error.Wrap(err)
|
||
|
|
}
|
||
|
|
aesgcm, err := cipher.NewGCM(block)
|
||
|
|
if err != nil {
|
||
|
|
return "", Error.Wrap(err)
|
||
|
|
}
|
||
|
|
data := aesgcm.Seal(nil, nonce, []byte(text), nil)
|
||
|
|
cipherText = base64.RawURLEncoding.EncodeToString(data)
|
||
|
|
// prepend version number to the cipher text
|
||
|
|
return "1" + cipherText, nil
|
||
|
|
}
|
||
|
|
|
||
|
|
func decrypt(cipherText string, secret []byte) (text string, err error) {
|
||
|
|
if cipherText == "" {
|
||
|
|
return "", Error.New("empty cipher text")
|
||
|
|
}
|
||
|
|
// check the version number, only "1" is supported for now
|
||
|
|
if cipherText[0] != '1' {
|
||
|
|
return "", Error.New("invalid version number")
|
||
|
|
}
|
||
|
|
data, err := base64.RawURLEncoding.DecodeString(cipherText[1:])
|
||
|
|
if err != nil {
|
||
|
|
return "", Error.Wrap(err)
|
||
|
|
}
|
||
|
|
key, nonce := getAESGCMKeyAndNonce(secret)
|
||
|
|
block, err := aes.NewCipher(key)
|
||
|
|
if err != nil {
|
||
|
|
return "", Error.Wrap(err)
|
||
|
|
}
|
||
|
|
aesgcm, err := cipher.NewGCM(block)
|
||
|
|
if err != nil {
|
||
|
|
return "", Error.Wrap(err)
|
||
|
|
}
|
||
|
|
decrypted, err := aesgcm.Open(nil, nonce, data, nil)
|
||
|
|
if err != nil {
|
||
|
|
return "", Error.Wrap(err)
|
||
|
|
}
|
||
|
|
return string(decrypted), nil
|
||
|
|
}
|
||
|
|
|
||
|
|
func getAESGCMKeyAndNonce(secret []byte) (key, nonce []byte) {
|
||
|
|
mac := hmac.New(sha512.New, secret)
|
||
|
|
mac.Write([]byte("enc"))
|
||
|
|
key = mac.Sum(nil)[:32]
|
||
|
|
mac.Reset()
|
||
|
|
mac.Write([]byte("nonce"))
|
||
|
|
nonce = mac.Sum(nil)[:12]
|
||
|
|
return key, nonce
|
||
|
|
}
|
||
|
|
|
||
|
|
func deriveSecret(secret []byte, child string) []byte {
|
||
|
|
mac := hmac.New(sha512.New, secret)
|
||
|
|
mac.Write([]byte(child))
|
||
|
|
return mac.Sum(nil)
|
||
|
|
}
|