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/*############################################################################
# Copyright 2016-2017 Intel Corporation
#
# 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
#
# http://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.
############################################################################*/
/*!
* \file
* \brief Commitment hash implementation.
*/
#include "epid/common/1.1/src/commitment.h"
#include <limits.h>
#include <stdio.h>
#include "epid/common/math/bignum.h"
#include "epid/common/math/src/bignum-internal.h"
#include "epid/common/src/endian_convert.h"
#include "epid/common/src/memory.h"
EpidStatus SetKeySpecificEpid11CommitValues(Epid11GroupPubKey const* pub_key,
Epid11CommitValues* values) {
static const Epid11Params params = {
#include "epid/common/1.1/src/epid11params_tate.inc"
};
if (!pub_key || !values) return kEpidBadArgErr;
values->p = params.p;
values->g1 = params.g1;
values->g2 = params.g2;
values->g3 = params.g3;
values->h1 = pub_key->h1;
values->h2 = pub_key->h2;
values->w = pub_key->w;
return kEpidNoErr;
}
EpidStatus SetCalculatedEpid11CommitValues(
Epid11G3ElemStr const* B, Epid11G3ElemStr const* K,
Epid11G1ElemStr const* T1, Epid11G1ElemStr const* T2, EcPoint const* R1,
EcPoint const* R2, EcPoint const* R3, FfElement const* R4, EcGroup* G1,
EcGroup* G3, FiniteField* GT, Epid11CommitValues* values) {
EpidStatus result;
if (!B || !K || !T1 || !T2 || !R1 || !R2 || !R3 || !R4 || !G1 || !G3 || !GT ||
!values) {
return kEpidBadArgErr;
}
values->B = *B;
values->K = *K;
values->T1 = *T1;
values->T2 = *T2;
result = WriteEcPoint(G1, R1, &values->R1, sizeof(values->R1));
if (kEpidNoErr != result) return result;
result = WriteEcPoint(G1, R2, &values->R2, sizeof(values->R2));
if (kEpidNoErr != result) return result;
result = WriteEcPoint(G3, R3, &values->R3, sizeof(values->R3));
if (kEpidNoErr != result) return result;
result = WriteFfElement(GT, R4, &values->R4, sizeof(values->R4));
if (kEpidNoErr != result) return result;
return kEpidNoErr;
}
EpidStatus CalculateEpid11CommitmentHash(Epid11CommitValues const* values,
void const* msg, uint32_t msg_len,
OctStr80 const* nd, Sha256Digest* c) {
EpidStatus result;
#pragma pack(1)
struct {
Sha256Digest t4;
OctStr80 nd;
uint32_t msg_len;
uint8_t msg[1];
}* t4mconcat_buf = NULL;
#pragma pack()
size_t max_msg_len =
SIZE_MAX - (sizeof(*t4mconcat_buf) - sizeof(t4mconcat_buf->msg));
size_t t4mconcat_size =
sizeof(*t4mconcat_buf) - sizeof(t4mconcat_buf->msg) + msg_len;
if (!values || !nd || !c) return kEpidBadArgErr;
if (!msg && (0 != msg_len)) {
// if message is non-empty it must have both length and content
return kEpidBadArgErr;
}
if (max_msg_len < (size_t)msg_len) {
return kEpidBadArgErr;
}
do {
// compute c = H(t4 || nd || msg_len || msg).
t4mconcat_buf = SAFE_ALLOC(t4mconcat_size);
if (!t4mconcat_buf) {
result = kEpidMemAllocErr;
break;
}
// Calculate c = Hash(t4 || nd || mSize || m) where t4 is Hash(p || g1 || g2
// || g3 || h1 || h2 || w || B || K || T1 || T2 || R1 || R2 || R3 || R4).
result = Sha256MessageDigest(values, sizeof(*values), &t4mconcat_buf->t4);
if (kEpidNoErr != result) break;
t4mconcat_buf->nd = *nd;
t4mconcat_buf->msg_len = ntohl(msg_len);
// place variable length msg into t4mconcat_buf
if (msg) {
if (0 != memcpy_S(&t4mconcat_buf->msg[0],
t4mconcat_size - sizeof(*t4mconcat_buf) +
sizeof(t4mconcat_buf->msg),
msg, msg_len)) {
result = kEpidBadArgErr;
break;
}
}
result = Sha256MessageDigest(t4mconcat_buf, t4mconcat_size, c);
if (kEpidNoErr != result) break;
result = kEpidNoErr;
} while (0);
SAFE_FREE(t4mconcat_buf);
return result;
}
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