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drone-go/plugin/internal/aesgcm/aesgcm.go

83 lines
2.0 KiB
Go

// Copyright 2018 Drone.IO Inc.
//
// 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 aesgcm
import (
"crypto/aes"
"crypto/cipher"
"crypto/rand"
"errors"
"io"
)
// error returned when the key length is less than the
// required size of 32 bytes.
var errInvalidKeyLength = errors.New("aesgcm: invalid key length")
// Encrypt encrypts the plaintext with the provided key and
// returns the raw, unencoded bytes.
func Encrypt(plaintext []byte, key *[32]byte) (ciphertext []byte, err 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())
_, err = io.ReadFull(rand.Reader, nonce)
if err != nil {
return nil, err
}
return gcm.Seal(nonce, nonce, plaintext, nil), nil
}
// Decrypt decrypts the raw, unencoded cihpertext with the provided key.
func Decrypt(ciphertext []byte, key *[32]byte) (plaintext []byte, err 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, errors.New("malformed ciphertext")
}
return gcm.Open(nil,
ciphertext[:gcm.NonceSize()],
ciphertext[gcm.NonceSize():],
nil,
)
}
// Key returns an encryption key.
func Key(s string) (*[32]byte, error) {
if len(s) < 32 {
return nil, errInvalidKeyLength
}
var key [32]byte
copy(key[:], s)
return &key, nil
}