random.cpp
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1 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
2 /*
3  * Copyright (c) 2013-2019 Regents of the University of California.
4  *
5  * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
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7  * ndn-cxx library is free software: you can redistribute it and/or modify it under the
8  * terms of the GNU Lesser General Public License as published by the Free Software
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13  * PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
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17  * <http://www.gnu.org/licenses/>.
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19  * See AUTHORS.md for complete list of ndn-cxx authors and contributors.
20  */
21 
22 #include "ndn-cxx/util/random.hpp"
23 #include "ndn-cxx/security/impl/openssl.hpp"
24 
25 namespace ndn {
26 namespace random {
27 
28 uint32_t
29 generateSecureWord32()
30 {
31  uint32_t random;
32  generateSecureBytes(reinterpret_cast<uint8_t*>(&random), sizeof(random));
33  return random;
34 }
35 
36 uint64_t
37 generateSecureWord64()
38 {
39  uint64_t random;
40  generateSecureBytes(reinterpret_cast<uint8_t*>(&random), sizeof(random));
41  return random;
42 }
43 
44 void
45 generateSecureBytes(uint8_t* bytes, size_t size)
46 {
47  if (RAND_bytes(bytes, size) != 1) {
48  NDN_THROW(std::runtime_error("Failed to generate random bytes (error code " +
49  to_string(ERR_get_error()) + ")"));
50  }
51 }
52 
53 RandomNumberEngine&
54 getRandomNumberEngine()
55 {
56  thread_local std::mt19937 rng = [] {
57  std::random_device rd;
58  // seed with 256 bits of entropy
59  std::seed_seq seeds{rd(), rd(), rd(), rd(), rd(), rd(), rd(), rd()};
60  return std::mt19937{seeds};
61  }();
62  return rng;
63 }
64 
65 uint32_t
66 generateWord32()
67 {
68  thread_local std::uniform_int_distribution<uint32_t> distribution;
69  return distribution(getRandomNumberEngine());
70 }
71 
72 uint64_t
73 generateWord64()
74 {
75  thread_local std::uniform_int_distribution<uint64_t> distribution;
76  return distribution(getRandomNumberEngine());
77 }
78 
79 } // namespace random
80 } // namespace ndn
ndn
Definition: data.cpp:26
ndn::random::generateSecureWord64
uint64_t generateSecureWord64()
Generate a cryptographically secure random integer from the range [0, 2^64)
Definition: random.cpp:37
ndn::to_string
std::string to_string(const T &val)
Definition: backports.hpp:101
ndn::random::RandomNumberEngine
std::mt19937 RandomNumberEngine
Definition: random.hpp:56
NDN_THROW
#define NDN_THROW(e)
Definition: exception.hpp:61
ndn::random::generateWord32
uint32_t generateWord32()
Generate a non-cryptographically-secure random integer in the range [0, 2^32)
Definition: random.cpp:66
ndn::random::generateSecureWord32
uint32_t generateSecureWord32()
Generate a cryptographically secure random integer from the range [0, 2^32)
Definition: random.cpp:29
ndn::random::getRandomNumberEngine
RandomNumberEngine & getRandomNumberEngine()
Returns a reference to a thread-local instance of a properly seeded PRNG.
Definition: random.cpp:54
ndn::random::generateWord64
uint64_t generateWord64()
Generate a non-cryptographically-secure random integer in the range [0, 2^64)
Definition: random.cpp:73
ndn::random::generateSecureBytes
void generateSecureBytes(uint8_t *bytes, size_t size)
Fill bytes of size with cryptographically secure random bytes.
Definition: random.cpp:45