Abseil Common Libraries (C++) (grcp 依赖)
https://abseil.io/
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
63 lines
2.3 KiB
63 lines
2.3 KiB
// Copyright 2017 The Abseil Authors. |
|
// |
|
// 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 |
|
// |
|
// https://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. |
|
|
|
#ifndef ABSL_RANDOM_INTERNAL_RANDEN_TRAITS_H_ |
|
#define ABSL_RANDOM_INTERNAL_RANDEN_TRAITS_H_ |
|
|
|
// HERMETIC NOTE: The randen_hwaes target must not introduce duplicate |
|
// symbols from arbitrary system and other headers, since it may be built |
|
// with different flags from other targets, using different levels of |
|
// optimization, potentially introducing ODR violations. |
|
|
|
#include <cstddef> |
|
|
|
#include "absl/base/config.h" |
|
|
|
namespace absl { |
|
ABSL_NAMESPACE_BEGIN |
|
namespace random_internal { |
|
|
|
// RANDen = RANDom generator or beetroots in Swiss German. |
|
// 'Strong' (well-distributed, unpredictable, backtracking-resistant) random |
|
// generator, faster in some benchmarks than std::mt19937_64 and pcg64_c32. |
|
// |
|
// RandenTraits contains the basic algorithm traits, such as the size of the |
|
// state, seed, sponge, etc. |
|
struct RandenTraits { |
|
// Size of the entire sponge / state for the randen PRNG. |
|
static constexpr size_t kStateBytes = 256; // 2048-bit |
|
|
|
// Size of the 'inner' (inaccessible) part of the sponge. Larger values would |
|
// require more frequent calls to RandenGenerate. |
|
static constexpr size_t kCapacityBytes = 16; // 128-bit |
|
|
|
// Size of the default seed consumed by the sponge. |
|
static constexpr size_t kSeedBytes = kStateBytes - kCapacityBytes; |
|
|
|
// Largest size for which security proofs are known. |
|
static constexpr size_t kFeistelBlocks = 16; |
|
|
|
// Type-2 generalized Feistel => one round function for every two blocks. |
|
static constexpr size_t kFeistelFunctions = kFeistelBlocks / 2; // = 8 |
|
|
|
// Ensures SPRP security and two full subblock diffusions. |
|
// Must be > 4 * log2(kFeistelBlocks). |
|
static constexpr size_t kFeistelRounds = 16 + 1; |
|
}; |
|
|
|
} // namespace random_internal |
|
ABSL_NAMESPACE_END |
|
} // namespace absl |
|
|
|
#endif // ABSL_RANDOM_INTERNAL_RANDEN_TRAITS_H_
|
|
|