80 lines
2.2 KiB
Go
80 lines
2.2 KiB
Go
// Copyright 2019 Drone IO, 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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package encrypt
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import (
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"crypto/cipher"
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"crypto/rand"
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"errors"
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"io"
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)
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// Aesgcm provides an encrypter that uses the aesgcm encryption
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// algorithm.
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type Aesgcm struct {
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block cipher.Block
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Compat bool
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}
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// Encrypt encrypts the plaintext using aesgcm.
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func (e *Aesgcm) Encrypt(plaintext string) ([]byte, error) {
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gcm, err := cipher.NewGCM(e.block)
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if err != nil {
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return nil, err
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}
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nonce := make([]byte, gcm.NonceSize())
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_, err = io.ReadFull(rand.Reader, nonce)
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if err != nil {
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return nil, err
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}
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return gcm.Seal(nonce, nonce, []byte(plaintext), nil), nil
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}
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// Decrypt decrypts the ciphertext using aesgcm.
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func (e *Aesgcm) Decrypt(ciphertext []byte) (string, error) {
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gcm, err := cipher.NewGCM(e.block)
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if err != nil {
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return "", err
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}
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if len(ciphertext) < gcm.NonceSize() {
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// if the decryption utility is running in compatibility
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// mode, it will return the ciphertext as plain text if
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// decryption fails. This should be used when running the
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// database in mixed-mode, where there is a mix of encrypted
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// and unencrypted content.
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if e.Compat {
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return string(ciphertext), nil
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}
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return "", errors.New("malformed ciphertext")
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}
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plaintext, err := gcm.Open(nil,
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ciphertext[:gcm.NonceSize()],
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ciphertext[gcm.NonceSize():],
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nil,
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)
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// if the decryption utility is running in compatibility
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// mode, it will return the ciphertext as plain text if
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// decryption fails. This should be used when running the
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// database in mixed-mode, where there is a mix of encrypted
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// and unencrypted content.
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if err != nil && e.Compat {
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return string(ciphertext), nil
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}
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return string(plaintext), err
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}
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