handle PRNG state in R_state + accumulator basis

* handle the PRNG state with R_state nested class
* add a private property R holding PRNG state to Fortuna
* add R_state properties as defined in Cryptography Engineering:
  * a generator instance
  * a reseed counter
  * 32 pools that the collected entropy is to be distributed over

* add initial definition of the Pool object and its initialization

* attempt to initialize PRNG in Fortuna constructor. wrap the
  initialization call in a try-catch block like a cultured person
* erase the string used to print data from random_data() after it's been
  used

CMakeLists.txt

@@ -175,7 +175,7 @@ add_subdirectory(lib/fmt EXCLUDE_FROM_ALL)
     endif(NOT CMAKE_EXE_LINKER_FLAGS MATCHES "-fuse-ld=lld")
   endif()
 
-add_executable(fortuna main.cpp generator.cpp generator.h fortuna.cpp fortuna.h)
+add_executable(fortuna main.cpp generator.cpp generator.h fortuna.cpp fortuna.h accumulator.cpp accumulator.h pool.cpp pool.h)
 # ref: https://cmake.org/pipermail/cmake/2016-May/063400.html
 target_link_libraries(fortuna
     PRIVATE cryptopp

accumulator.cpp

@@ -0,0 +1,12 @@
+#ifndef FORTUNA_ACCUMULATOR_CPP
+#define FORTUNA_ACCUMULATOR_CPP
+
+#include "accumulator.h"
+
+namespace fortuna {
+namespace accumulator {
+
+} //namespace accumulator
+} //namespace fortuna
+
+#endif//FORTUNA_ACCUMULATOR_CPP

accumulator.h

@@ -0,0 +1,17 @@
+#ifndef FORTUNA_ACCUMULATOR_H
+#define FORTUNA_ACCUMULATOR_H
+
+#include "pool.h"
+
+namespace fortuna {
+namespace accumulator {
+
+class Accumulator {
+	public:
+		unsigned int init_pool_num{0};
+}; //class Accumulator
+
+} //namespace accumulator
+} //namespace fortuna
+
+#endif//FORTUNA_ACCUMULATOR_H

fortuna.cpp

@@ -3,6 +3,7 @@
 
 #include "fortuna.h"
 
+#include <cryptopp/cryptlib.h>
 #include <cryptopp/osrng.h>
 #include <cryptopp/hex.h>
 #include <cryptopp/filters.h>
@@ -10,20 +11,22 @@
 #include <cryptopp/ccm.h>
 #include <fmt/core.h>
 
-#include <cassert>
-#include <cstring>
-
 
 namespace fortuna {
 	Fortuna::Fortuna(){
+		try {
+			initialize_prng();
+		} catch(CryptoPP::Exception& e) {
+			fmt::print(stderr, "{}\n", e.what());
+		}
 	}
 	Fortuna::~Fortuna() = default;
 
-
 	auto Fortuna::random_data(unsigned int n_bytes) -> void {
-		std::string n{gen.generate_random_data(n_bytes)};
+		std::string n{R.Gen.generate_random_data(n_bytes)};
 		fmt::print("got you {} proper bytes from generate_random_data -> {}\n",
 				n_bytes, n);
+		n.erase();
 	} //random_data
 
 } // namespace fortuna

fortuna.h

@@ -2,17 +2,66 @@
 #define FORTUNA_FORTUNA_H
 
 #include "generator.h"
+#include "accumulator.h"
+
+#include <fmt/core.h>
 
 namespace fortuna {
 
 class Fortuna {
 public:
+	// in microseconds
+	static constexpr const unsigned int reseed_interval{10000};
+	static constexpr const char num_of_pools{32};
+
 	Fortuna();
 	~Fortuna();
+
 	auto random_data(unsigned int) -> void;
-private:
-	generator::Generator gen;
-};
+
+	auto set_reseed_ctr_to_null() -> void {
+		Fortuna::R.null_da_ctr();
+	}
+
+	auto initialize_prng() -> void {
+		// TODO(me): handle the reseeds here as per Cryptography Engineering,
+		// p. 153
+		set_reseed_ctr_to_null();
+		R.initialize_pools();
+		fmt::print("PRNG initialized\n");
+	};
+
+	// PRNG state
+	class R_state {
+	friend fortuna::Fortuna;
+	public:
+		R_state(){};
+		~R_state() = default;
+
+	protected:
+		auto null_da_ctr() -> void {
+			reseed_ctr = 0x00;
+			fmt::print("reseed_ctr set to 0x00\n");
+		}
+
+		auto initialize_pools() -> void {
+			for (unsigned int i = 0; i < num_of_pools; ++i) {
+				pools[i].initialize_pool(i);
+			}
+		}
+
+	private:
+		generator::Generator Gen;
+		#pragma GCC diagnostic push
+		#pragma GCC diagnostic ignored "-Wpedantic"
+		unsigned __int128 reseed_ctr;
+		#pragma GCC diagnostic pop
+		accumulator::Pool pools[num_of_pools];
+	}; // class R_state
+
+	fortuna::Fortuna::R_state R;
+
+}; // class Fortuna
 
 } // namespace fortuna
 

pool.cpp

@@ -0,0 +1,12 @@
+#ifndef FORTUNA_POOL_CPP
+#define FORTUNA_POOL_CPP
+
+#include "pool.h"
+
+namespace fortuna {
+namespace accumulator {
+
+} //namespace accumulator
+} //namespace fortuna
+
+#endif//FORTUNA_POOL_CPP

pool.h

@@ -0,0 +1,34 @@
+#ifndef FORTUNA_POOL_H
+#define FORTUNA_POOL_H
+
+#include <fmt/core.h>
+
+namespace fortuna {
+namespace accumulator {
+
+class Pool {
+public:
+	Pool(){};
+	~Pool() = default;
+
+	// TODO(me): this public setter should be fixed?
+	auto set_id(unsigned int id) -> void {
+		pool_id = id;
+	}
+
+	auto get_id() -> unsigned int;
+
+	auto initialize_pool(unsigned int id) -> void {
+		set_id(id);
+		fmt::print("Pool{{{}}} initialized to empty string\n", id);
+	}
+
+private:
+	unsigned int pool_id{0};
+
+}; // class Pool
+
+} //namespace accumulator
+} //namespace fortuna
+
+#endif//FORTUNA_POOL_H