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encrypter.go
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/
encrypter.go
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/*
* Copyright 2018 The Service Manager Authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package security
import (
"context"
"crypto/aes"
"crypto/cipher"
"crypto/rand"
"fmt"
"io"
)
// Encrypter provides functionality to encrypt and decrypt data
//go:generate counterfeiter . Encrypter
type Encrypter interface {
Encrypt(ctx context.Context, plaintext, key []byte) ([]byte, error)
Decrypt(ctx context.Context, ciphertext, key []byte) ([]byte, error)
}
// AESEncrypter is an encrypter that fetches the encryption key from a remote location
type AESEncrypter struct {
}
// Encrypt encrypts the plaintext with the provided key using AES
func (e *AESEncrypter) Encrypt(_ context.Context, plaintext []byte, key []byte) ([]byte, error) {
block, err := aes.NewCipher(key)
if err != nil {
return nil, err
}
gcm, err := cipher.NewGCM(block)
if err != nil {
return nil, err
}
nonce := make([]byte, gcm.NonceSize())
if _, err := io.ReadFull(rand.Reader, nonce); err != nil {
return nil, err
}
return gcm.Seal(nonce, nonce, plaintext, nil), nil
}
// Decrypt decrypts the cipher text with the provided key using AES
func (e *AESEncrypter) Decrypt(_ context.Context, ciphertext []byte, key []byte) ([]byte, error) {
block, err := aes.NewCipher(key)
if err != nil {
return nil, err
}
gcm, err := cipher.NewGCM(block)
if err != nil {
return nil, err
}
if len(ciphertext) < gcm.NonceSize() {
return nil, fmt.Errorf("malformed ciphertext")
}
return gcm.Open(nil,
ciphertext[:gcm.NonceSize()],
ciphertext[gcm.NonceSize():],
nil,
)
}