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/*
* (C) 2015,2016 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#ifndef ECC_HELPERS_H_
#define ECC_HELPERS_H_
#include "fuzzers.h"
#include <botan/ec_group.h>
#include <botan/reducer.h>
namespace {
inline std::ostream& operator<<(std::ostream& o, const Botan::PointGFp& point)
{
o << point.get_affine_x() << "," << point.get_affine_y();
return o;
}
void check_ecc_math(const Botan::EC_Group& group,
const uint8_t in[], size_t len)
{
// These depend only on the group, which is also static
static const Botan::PointGFp base_point = group.get_base_point();
// This is shared across runs to reduce overhead
static std::vector<Botan::BigInt> ws(Botan::PointGFp::WORKSPACE_SIZE);
const size_t hlen = len / 2;
const Botan::BigInt a = Botan::BigInt::decode(in, hlen);
const Botan::BigInt b = Botan::BigInt::decode(in + hlen, len - hlen);
const Botan::BigInt c = a + b;
const Botan::PointGFp P1 = base_point * a;
const Botan::PointGFp Q1 = base_point * b;
const Botan::PointGFp R1 = base_point * c;
const Botan::PointGFp S1 = P1 + Q1;
const Botan::PointGFp T1 = Q1 + P1;
FUZZER_ASSERT_EQUAL(S1, R1);
FUZZER_ASSERT_EQUAL(T1, R1);
const Botan::PointGFp P2 = group.blinded_base_point_multiply(a, fuzzer_rng(), ws);
const Botan::PointGFp Q2 = group.blinded_base_point_multiply(b, fuzzer_rng(), ws);
const Botan::PointGFp R2 = group.blinded_base_point_multiply(c, fuzzer_rng(), ws);
const Botan::PointGFp S2 = P2 + Q2;
const Botan::PointGFp T2 = Q2 + P2;
FUZZER_ASSERT_EQUAL(S2, R2);
FUZZER_ASSERT_EQUAL(T2, R2);
const Botan::PointGFp P3 = group.blinded_var_point_multiply(base_point, a, fuzzer_rng(), ws);
const Botan::PointGFp Q3 = group.blinded_var_point_multiply(base_point, b, fuzzer_rng(), ws);
const Botan::PointGFp R3 = group.blinded_var_point_multiply(base_point, c, fuzzer_rng(), ws);
const Botan::PointGFp S3 = P3 + Q3;
const Botan::PointGFp T3 = Q3 + P3;
FUZZER_ASSERT_EQUAL(S3, R3);
FUZZER_ASSERT_EQUAL(T3, R3);
FUZZER_ASSERT_EQUAL(S1, S2);
FUZZER_ASSERT_EQUAL(S1, S3);
}
}
#endif
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