chromium/components/reporting/encryption/encryption.h

// Copyright 2020 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef COMPONENTS_REPORTING_ENCRYPTION_ENCRYPTION_H_
#define COMPONENTS_REPORTING_ENCRYPTION_ENCRYPTION_H_

#include <optional>
#include <string>
#include <string_view>
#include <utility>

#include "base/functional/callback.h"
#include "base/memory/ref_counted.h"
#include "base/memory/scoped_refptr.h"
#include "base/task/sequenced_task_runner.h"
#include "components/reporting/proto/synced/record.pb.h"
#include "components/reporting/util/status.h"
#include "components/reporting/util/statusor.h"

namespace reporting {

// Full implementation of Encryptor, intended for use in reporting client.
// ChaCha20_Poly1305 AEAD encryption of a record in place with symmetric key.
// Curve25519 encryption of the symmetric key with asymmetric public key.
//
// We generate new Curve25519 public/private keys pair for each record.
// Then we produce Curve25519 shared secret from our private key and peer's
// public key, and use it for ChaCha20_Poly1305 AEAD encryption of the record.
// We send out our public value (calling it encrypted symmetric key) together
// with encrypted record.
//
// Upon receiving the encrypted message the peer will produce the same shared
// secret by combining their private key and our public key, and use it as
// a symmetric key for ChaCha20_Poly1305 decryption and validation of the
// record.
//
// Instantiated by a factory:
//   StatusOr<scoped_refptr<Encryptor>> Create();
// The implementation class should never be used directly by the client code.
class Encryptor : public base::RefCountedThreadSafe<Encryptor> { … };

}  // namespace reporting

#endif  // COMPONENTS_REPORTING_ENCRYPTION_ENCRYPTION_H_