Abseil Common Libraries (C++) (grcp 依赖)
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59 lines
2.3 KiB
59 lines
2.3 KiB
// Copyright 2017 The Abseil Authors. |
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// |
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// Licensed under the Apache License, Version 2.0 (the "License"); |
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// you may not use this file except in compliance with the License. |
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// You may obtain a copy of the License at |
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// |
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// https://www.apache.org/licenses/LICENSE-2.0 |
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// |
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// Unless required by applicable law or agreed to in writing, software |
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// distributed under the License is distributed on an "AS IS" BASIS, |
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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// See the License for the specific language governing permissions and |
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// limitations under the License. |
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#ifndef ABSL_RANDOM_INTERNAL_RANDEN_TRAITS_H_ |
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#define ABSL_RANDOM_INTERNAL_RANDEN_TRAITS_H_ |
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// HERMETIC NOTE: The randen_hwaes target must not introduce duplicate |
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// symbols from arbitrary system and other headers, since it may be built |
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// with different flags from other targets, using different levels of |
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// optimization, potentially introducing ODR violations. |
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#include <cstddef> |
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namespace absl { |
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namespace random_internal { |
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// RANDen = RANDom generator or beetroots in Swiss German. |
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// 'Strong' (well-distributed, unpredictable, backtracking-resistant) random |
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// generator, faster in some benchmarks than std::mt19937_64 and pcg64_c32. |
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// |
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// RandenTraits contains the basic algorithm traits, such as the size of the |
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// state, seed, sponge, etc. |
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struct RandenTraits { |
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// Size of the entire sponge / state for the randen PRNG. |
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static constexpr size_t kStateBytes = 256; // 2048-bit |
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// Size of the 'inner' (inaccessible) part of the sponge. Larger values would |
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// require more frequent calls to RandenGenerate. |
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static constexpr size_t kCapacityBytes = 16; // 128-bit |
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// Size of the default seed consumed by the sponge. |
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static constexpr size_t kSeedBytes = kStateBytes - kCapacityBytes; |
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// Largest size for which security proofs are known. |
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static constexpr size_t kFeistelBlocks = 16; |
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// Type-2 generalized Feistel => one round function for every two blocks. |
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static constexpr size_t kFeistelFunctions = kFeistelBlocks / 2; // = 8 |
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// Ensures SPRP security and two full subblock diffusions. |
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// Must be > 4 * log2(kFeistelBlocks). |
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static constexpr size_t kFeistelRounds = 16 + 1; |
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}; |
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} // namespace random_internal |
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} // namespace absl |
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#endif // ABSL_RANDOM_INTERNAL_RANDEN_TRAITS_H_
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