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matterbridge/vendor/go.mau.fi/whatsmeow/util/gcmutil/gcm.go

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2022-11-26 23:42:16 +00:00
// Copyright (c) 2022 Tulir Asokan
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.
package gcmutil
import (
"crypto/aes"
"crypto/cipher"
"fmt"
)
func Prepare(secretKey []byte) (gcm cipher.AEAD, err error) {
var block cipher.Block
if block, err = aes.NewCipher(secretKey); err != nil {
err = fmt.Errorf("failed to initialize AES cipher: %w", err)
} else if gcm, err = cipher.NewGCM(block); err != nil {
err = fmt.Errorf("failed to initialize GCM: %w", err)
}
return
}
func Decrypt(secretKey, iv, ciphertext, additionalData []byte) ([]byte, error) {
if gcm, err := Prepare(secretKey); err != nil {
return nil, err
} else if plaintext, decryptErr := gcm.Open(nil, iv, ciphertext, additionalData); decryptErr != nil {
return nil, decryptErr
} else {
return plaintext, nil
}
}
func Encrypt(secretKey, iv, plaintext, additionalData []byte) ([]byte, error) {
if gcm, err := Prepare(secretKey); err != nil {
return nil, err
} else {
return gcm.Seal(nil, iv, plaintext, additionalData), nil
}
}