quic/core/crypto/quic_random.h

// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef QUICHE_QUIC_CORE_CRYPTO_QUIC_RANDOM_H_
#define QUICHE_QUIC_CORE_CRYPTO_QUIC_RANDOM_H_

#include <cstddef>
#include <cstdint>

#include "quic/platform/api/quic_export.h"

namespace quic {

// The interface for a random number generator.
class QUIC_EXPORT_PRIVATE QuicRandom {
 public:
  virtual ~QuicRandom() {}

  // Returns the default random number generator, which is cryptographically
  // secure and thread-safe.
  static QuicRandom* GetInstance();

  // Generates |len| random bytes in the |data| buffer.
  virtual void RandBytes(void* data, size_t len) = 0;

  // Returns a random number in the range [0, kuint64max].
  virtual uint64_t RandUint64() = 0;

  // Generates |len| random bytes in the |data| buffer. This MUST NOT be used
  // for any application that requires cryptographically-secure randomness.
  virtual void InsecureRandBytes(void* data, size_t len) = 0;

  // Returns a random number in the range [0, kuint64max]. This MUST NOT be used
  // for any application that requires cryptographically-secure randomness.
  virtual uint64_t InsecureRandUint64() = 0;
};

// A class that generates non-cryptographically-secure random numbers. It uses
// a QuicRandom instance to seed its initial randomness. This MUST NOT be used
// for any application that requires cryptographically-secure randomness.
class QUIC_EXPORT_PRIVATE QuicInsecureRandom {
 public:
  // |random| is only used during construction of the QuicInsecureRandom to seed
  // its inital state.
  explicit QuicInsecureRandom(QuicRandom* random);

  // Generates |len| random bytes in the |data| buffer. This MUST NOT be used
  // for any application that requires cryptographically-secure randomness.
  void InsecureRandBytes(void* data, size_t len);

  // Returns a random number in the range [0, kuint64max]. This MUST NOT be used
  // for any application that requires cryptographically-secure randomness.
  uint64_t InsecureRandUint64();

 private:
  uint64_t rng_state_[4];
};

}  // namespace quic

#endif  // QUICHE_QUIC_CORE_CRYPTO_QUIC_RANDOM_H_