randen.h (3006B)
1 // Copyright 2017 The Abseil Authors. 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // https://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 15 #ifndef ABSL_RANDOM_INTERNAL_RANDEN_H_ 16 #define ABSL_RANDOM_INTERNAL_RANDEN_H_ 17 18 #include <cstddef> 19 20 #include "absl/random/internal/platform.h" 21 #include "absl/random/internal/randen_hwaes.h" 22 #include "absl/random/internal/randen_slow.h" 23 #include "absl/random/internal/randen_traits.h" 24 25 namespace absl { 26 ABSL_NAMESPACE_BEGIN 27 namespace random_internal { 28 29 // RANDen = RANDom generator or beetroots in Swiss High German. 30 // 'Strong' (well-distributed, unpredictable, backtracking-resistant) random 31 // generator, faster in some benchmarks than std::mt19937_64 and pcg64_c32. 32 // 33 // Randen implements the basic state manipulation methods. 34 class Randen { 35 public: 36 static constexpr size_t kStateBytes = RandenTraits::kStateBytes; 37 static constexpr size_t kCapacityBytes = RandenTraits::kCapacityBytes; 38 static constexpr size_t kSeedBytes = RandenTraits::kSeedBytes; 39 40 ~Randen() = default; 41 42 Randen(); 43 44 // Generate updates the randen sponge. The outer portion of the sponge 45 // (kCapacityBytes .. kStateBytes) may be consumed as PRNG state. 46 // REQUIRES: state points to kStateBytes of state. 47 inline void Generate(void* state) const { 48 #if ABSL_RANDOM_INTERNAL_AES_DISPATCH 49 // HW AES Dispatch. 50 if (has_crypto_) { 51 RandenHwAes::Generate(keys_, state); 52 } else { 53 RandenSlow::Generate(keys_, state); 54 } 55 #elif ABSL_HAVE_ACCELERATED_AES 56 // HW AES is enabled. 57 RandenHwAes::Generate(keys_, state); 58 #else 59 // HW AES is disabled. 60 RandenSlow::Generate(keys_, state); 61 #endif 62 } 63 64 // Absorb incorporates additional seed material into the randen sponge. After 65 // absorb returns, Generate must be called before the state may be consumed. 66 // REQUIRES: seed points to kSeedBytes of seed. 67 // REQUIRES: state points to kStateBytes of state. 68 inline void Absorb(const void* seed, void* state) const { 69 #if ABSL_RANDOM_INTERNAL_AES_DISPATCH 70 // HW AES Dispatch. 71 if (has_crypto_) { 72 RandenHwAes::Absorb(seed, state); 73 } else { 74 RandenSlow::Absorb(seed, state); 75 } 76 #elif ABSL_HAVE_ACCELERATED_AES 77 // HW AES is enabled. 78 RandenHwAes::Absorb(seed, state); 79 #else 80 // HW AES is disabled. 81 RandenSlow::Absorb(seed, state); 82 #endif 83 } 84 85 private: 86 const void* keys_; 87 #if ABSL_RANDOM_INTERNAL_AES_DISPATCH 88 bool has_crypto_; 89 #endif 90 }; 91 92 } // namespace random_internal 93 ABSL_NAMESPACE_END 94 } // namespace absl 95 96 #endif // ABSL_RANDOM_INTERNAL_RANDEN_H_