src/fuzzer/redc_p256.cpp


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31

/*
* (C) 2015,2016 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/

#include "fuzzers.h"
#include <botan/reducer.h>
#include <botan/curve_nistp.h>

void fuzz(const uint8_t in[], size_t len)
   {
   if(len > 2*256/8)
      return;

   static const Botan::BigInt& prime = Botan::prime_p256();
   static const Botan::BigInt prime_2 = prime * prime;
   static Botan::Modular_Reducer prime_redc(prime);

   Botan::BigInt input = Botan::BigInt::decode(in, len);

   if(input < prime_2)
      {
      const Botan::BigInt ref = prime_redc.reduce(input);

      Botan::secure_vector<Botan::word> ws;
      Botan::redc_p256(input, ws);

      FUZZER_ASSERT_EQUAL(ref, input);
      }
   }