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/*
* Copyright 2019 Google LLC.
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "private_join_and_compute/crypto/ec_point.h"
#include <string>
#include <utility>
#include <vector>
#include "absl/strings/str_cat.h"
#include "private_join_and_compute/crypto/big_num.h"
#include "private_join_and_compute/crypto/context.h"
#include "private_join_and_compute/crypto/openssl.inc"
#include "private_join_and_compute/util/status.inc"
namespace private_join_and_compute {
ECPoint::ECPoint(const EC_GROUP* group, BN_CTX* bn_ctx)
: bn_ctx_(bn_ctx), group_(group) {
point_ = ECPointPtr(EC_POINT_new(group_));
}
ECPoint::ECPoint(const EC_GROUP* group, BN_CTX* bn_ctx, const BigNum& x,
const BigNum& y)
: ECPoint::ECPoint(group, bn_ctx) {
CRYPTO_CHECK(1 == EC_POINT_set_affine_coordinates_GFp(
group_, point_.get(), x.GetConstBignumPtr(),
y.GetConstBignumPtr(), bn_ctx_));
}
ECPoint::ECPoint(const EC_GROUP* group, BN_CTX* bn_ctx, ECPointPtr point)
: ECPoint::ECPoint(group, bn_ctx) {
point_ = std::move(point);
}
StatusOr<std::string> ECPoint::ToBytesCompressed() const {
int length = EC_POINT_point2oct(
group_, point_.get(), POINT_CONVERSION_COMPRESSED, nullptr, 0, bn_ctx_);
std::vector<unsigned char> bytes(length);
if (0 == EC_POINT_point2oct(group_, point_.get(), POINT_CONVERSION_COMPRESSED,
bytes.data(), length, bn_ctx_)) {
return InternalError(
absl::StrCat("EC_POINT_point2oct failed:", OpenSSLErrorString()));
}
return std::string(reinterpret_cast<char*>(bytes.data()), bytes.size());
}
StatusOr<std::string> ECPoint::ToBytesUnCompressed() const {
int length = EC_POINT_point2oct(
group_, point_.get(), POINT_CONVERSION_UNCOMPRESSED, nullptr, 0, bn_ctx_);
std::vector<unsigned char> bytes(length);
if (0 == EC_POINT_point2oct(group_, point_.get(),
POINT_CONVERSION_UNCOMPRESSED, bytes.data(),
length, bn_ctx_)) {
return InternalError(
absl::StrCat("EC_POINT_point2oct failed:", OpenSSLErrorString()));
}
return std::string(reinterpret_cast<char*>(bytes.data()), bytes.size());
}
StatusOr<ECPoint> ECPoint::Mul(const BigNum& scalar) const {
ECPoint r = ECPoint(group_, bn_ctx_);
if (1 != EC_POINT_mul(group_, r.point_.get(), nullptr, point_.get(),
scalar.GetConstBignumPtr(), bn_ctx_)) {
return InternalError(
absl::StrCat("EC_POINT_mul failed:", OpenSSLErrorString()));
}
return std::move(r);
}
StatusOr<ECPoint> ECPoint::Add(const ECPoint& point) const {
ECPoint r = ECPoint(group_, bn_ctx_);
if (1 != EC_POINT_add(group_, r.point_.get(), point_.get(),
point.point_.get(), bn_ctx_)) {
return InternalError(
absl::StrCat("EC_POINT_add failed:", OpenSSLErrorString()));
}
return std::move(r);
}
StatusOr<ECPoint> ECPoint::Clone() const {
ECPoint r = ECPoint(group_, bn_ctx_);
if (1 != EC_POINT_copy(r.point_.get(), point_.get())) {
return InternalError(
absl::StrCat("EC_POINT_copy failed:", OpenSSLErrorString()));
}
return std::move(r);
}
StatusOr<ECPoint> ECPoint::Inverse() const {
// Create a copy of this.
ASSIGN_OR_RETURN(ECPoint inv, Clone());
// Invert the copy in-place.
if (1 != EC_POINT_invert(group_, inv.point_.get(), bn_ctx_)) {
return InternalError(
absl::StrCat("EC_POINT_invert failed:", OpenSSLErrorString()));
}
return std::move(inv);
}
bool ECPoint::IsPointAtInfinity() const {
return EC_POINT_is_at_infinity(group_, point_.get());
}
bool ECPoint::CompareTo(const ECPoint& point) const {
return 0 == EC_POINT_cmp(group_, point_.get(), point.point_.get(), bn_ctx_);
}
} // namespace private_join_and_compute
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