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Copy pathencryption.go
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69 lines (63 loc) · 2.08 KB
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// Copyright © 2020 The Things Network Foundation, The Things Industries B.V.
//
// 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 crypto
import (
"crypto/aes"
"crypto/cipher"
"crypto/rand"
"io"
"go.thethings.network/lorawan-stack/v3/pkg/errors"
"go.thethings.network/lorawan-stack/v3/pkg/types"
)
var errMalformedCipherText = errors.DefineInvalidArgument("malformed_cipher_text", "malformed cipher text")
// Encrypt encrypts a plain text message.
// Uses AES128 keys in GCM (Galois/Counter Mode).
// Since GCM uses a nonce, the encrypted message will be different each time the operation is run for the same set of inputs.
// The returned cipher is in the format |nonce(12)|tag(16)|encrypted(plaintextLen)|.
func Encrypt(key types.AES128Key, plaintext []byte) ([]byte, error) {
cipherBlock, err := aes.NewCipher(key[:])
if err != nil {
return nil, err
}
gcm, err := cipher.NewGCM(cipherBlock)
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 an encrypted message.
// Uses AES128 keys in GCM (Galois/Counter Mode).
func Decrypt(key types.AES128Key, encrypted []byte) ([]byte, error) {
cipherBlock, err := aes.NewCipher(key[:])
if err != nil {
return nil, err
}
gcm, err := cipher.NewGCM(cipherBlock)
if err != nil {
return nil, err
}
if len(encrypted) < gcm.NonceSize() {
return nil, errMalformedCipherText
}
return gcm.Open(nil,
encrypted[:gcm.NonceSize()],
encrypted[gcm.NonceSize():],
nil,
)
}