surtur
01eadae32f
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* declare and implement Generator class and member methods * create an instance of Generator in main * call initialize_generator() from main
93 lines
2.0 KiB
C++
93 lines
2.0 KiB
C++
#include <cmath>
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#include <cassert>
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#include <cstdint>
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#include <stdexcept>
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#include <tuple>
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#include "generator.h"
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#ifndef FORTUNA_GENERATOR_CPP
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#define FORTUNA_GENERATOR_CPP
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namespace fortuna {
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namespace generator {
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using namespace std;
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struct Generator::G_state{
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int64_t k;
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unsigned __int128 ctr;
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};
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void Generator::initialize_generator(){
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// Generator::G_state *G = new G_state; // -> was told to use auto by
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// clang-tidy...
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auto G = new Generator::G_state{};
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G->k = 0;
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G->ctr = 0;
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k = 0;
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ctr = 0;
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printf("Generator initialized\n");
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delete(G);
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};
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auto Generator::get_state() -> G_state {
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return G_state{};
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}
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auto Generator::reseed(G_state G, const string& s) -> G_state {
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string to_be_hashed = std::to_string(G.k) + s;
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G.k = do_sha(stoul(to_be_hashed));
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G.ctr++;
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return G;
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}
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auto Generator::do_sha(int64_t key_with_seed) -> int64_t {
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/* do sha256 */
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int64_t shastring = key_with_seed + 1;
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return shastring;
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}
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auto Generator::do_crypto(int64_t k, unsigned __int128 ctr) -> string {
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/* this function calls the block cipher
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* returns a string of k*(16 bytes);
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* do whatever atm */
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k = 0;
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ctr = 0;
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return "";
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}
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auto Generator::generate_blocks(G_state G, int k_blocks) -> tuple<string, G_state> {
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assert (G.ctr!=0);
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string r = "";
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for (int i = 0; i < k_blocks; ++i) {
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r += do_crypto(G.k, G.ctr);
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G.ctr++;
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}
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return {r, G};
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}
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auto Generator::generate_random_data(G_state G, uint n) -> tuple<string, G_state> {
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string r = "";
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if (n < 0){
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/* this should not be possible */
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printf("[*] error: n cannot be < 0\n");
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throw invalid_argument("n cannot be < 0");
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} else if (n > pow(2,20)){
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printf("[*] error: n cannot be > 2^20\n");
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throw invalid_argument("n cannot be > 2^20");
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}
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/* do magic to compute r
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* r ← first-n-bytes(GenerateBlocks(G, ceil(n/16) )) */
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string rr = std::get<0>(generate_blocks(G,ceil(n/16)));
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r = rr.substr(0,n);
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/* re-key */
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// TODO: check conversions
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G.k = stoul(std::get<0>(generate_blocks(G, 2)));
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return {r, G};
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};
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} // namespace generator
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} // namespace fortuna
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#endif
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