mirror of
https://github.com/octoleo/restic.git
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167 lines
4.2 KiB
Go
167 lines
4.2 KiB
Go
/*
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* Minio Go Library for Amazon S3 Compatible Cloud Storage
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* Copyright 2017 Minio, Inc.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package encrypt
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import (
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"crypto/aes"
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"crypto/rand"
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"crypto/rsa"
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"crypto/x509"
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"errors"
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)
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// Key - generic interface to encrypt/decrypt a key.
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// We use it to encrypt/decrypt content key which is the key
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// that encrypt/decrypt object data.
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type Key interface {
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// Encrypt data using to the set encryption key
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Encrypt([]byte) ([]byte, error)
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// Decrypt data using to the set encryption key
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Decrypt([]byte) ([]byte, error)
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}
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// SymmetricKey - encrypts data with a symmetric master key
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type SymmetricKey struct {
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masterKey []byte
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}
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// Encrypt passed bytes
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func (s *SymmetricKey) Encrypt(plain []byte) ([]byte, error) {
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// Initialize an AES encryptor using a master key
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keyBlock, err := aes.NewCipher(s.masterKey)
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if err != nil {
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return []byte{}, err
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}
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// Pad the key before encryption
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plain, _ = pkcs5Pad(plain, aes.BlockSize)
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encKey := []byte{}
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encPart := make([]byte, aes.BlockSize)
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// Encrypt the passed key by block
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for {
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if len(plain) < aes.BlockSize {
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break
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}
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// Encrypt the passed key
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keyBlock.Encrypt(encPart, plain[:aes.BlockSize])
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// Add the encrypted block to the total encrypted key
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encKey = append(encKey, encPart...)
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// Pass to the next plain block
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plain = plain[aes.BlockSize:]
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}
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return encKey, nil
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}
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// Decrypt passed bytes
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func (s *SymmetricKey) Decrypt(cipher []byte) ([]byte, error) {
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// Initialize AES decrypter
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keyBlock, err := aes.NewCipher(s.masterKey)
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if err != nil {
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return nil, err
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}
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var plain []byte
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plainPart := make([]byte, aes.BlockSize)
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// Decrypt the encrypted data block by block
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for {
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if len(cipher) < aes.BlockSize {
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break
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}
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keyBlock.Decrypt(plainPart, cipher[:aes.BlockSize])
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// Add the decrypted block to the total result
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plain = append(plain, plainPart...)
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// Pass to the next cipher block
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cipher = cipher[aes.BlockSize:]
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}
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// Unpad the resulted plain data
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plain, err = pkcs5Unpad(plain, aes.BlockSize)
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if err != nil {
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return nil, err
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}
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return plain, nil
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}
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// NewSymmetricKey generates a new encrypt/decrypt crypto using
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// an AES master key password
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func NewSymmetricKey(b []byte) *SymmetricKey {
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return &SymmetricKey{masterKey: b}
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}
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// AsymmetricKey - struct which encrypts/decrypts data
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// using RSA public/private certificates
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type AsymmetricKey struct {
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publicKey *rsa.PublicKey
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privateKey *rsa.PrivateKey
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}
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// Encrypt data using public key
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func (a *AsymmetricKey) Encrypt(plain []byte) ([]byte, error) {
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cipher, err := rsa.EncryptPKCS1v15(rand.Reader, a.publicKey, plain)
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if err != nil {
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return nil, err
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}
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return cipher, nil
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}
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// Decrypt data using public key
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func (a *AsymmetricKey) Decrypt(cipher []byte) ([]byte, error) {
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cipher, err := rsa.DecryptPKCS1v15(rand.Reader, a.privateKey, cipher)
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if err != nil {
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return nil, err
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}
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return cipher, nil
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}
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// NewAsymmetricKey - generates a crypto module able to encrypt/decrypt
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// data using a pair for private and public key
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func NewAsymmetricKey(privData []byte, pubData []byte) (*AsymmetricKey, error) {
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// Parse private key from passed data
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priv, err := x509.ParsePKCS8PrivateKey(privData)
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if err != nil {
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return nil, err
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}
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privKey, ok := priv.(*rsa.PrivateKey)
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if !ok {
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return nil, errors.New("not a valid private key")
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}
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// Parse public key from passed data
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pub, err := x509.ParsePKIXPublicKey(pubData)
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if err != nil {
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return nil, err
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}
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pubKey, ok := pub.(*rsa.PublicKey)
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if !ok {
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return nil, errors.New("not a valid public key")
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}
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// Associate the private key with the passed public key
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privKey.PublicKey = *pubKey
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return &AsymmetricKey{
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publicKey: pubKey,
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privateKey: privKey,
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}, nil
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}
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