1 /*############################################################################
2 # Copyright 2017 Intel Corporation
3 #
4 # Licensed under the Apache License, Version 2.0 (the "License");
5 # you may not use this file except in compliance with the License.
6 # You may obtain a copy of the License at
7 #
8 # http://www.apache.org/licenses/LICENSE-2.0
9 #
10 # Unless required by applicable law or agreed to in writing, software
11 # distributed under the License is distributed on an "AS IS" BASIS,
12 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 # See the License for the specific language governing permissions and
14 # limitations under the License.
15 ############################################################################*/
16 /// Host signing helper implementation
17 /*! \file */
18
19 #include "epid/member/src/sign_commitment.h"
20
21 #include "epid/common/math/ecgroup.h"
22 #include "epid/common/src/commitment.h"
23
24 /// Handle SDK Error with Break
25 #define BREAK_ON_EPID_ERROR(ret) \
26 if (kEpidNoErr != (ret)) { \
27 break; \
28 }
29
HashSignCommitment(FiniteField * Fp,HashAlg hash_alg,GroupPubKey const * pub_key,SignCommitOutput const * commit_out,void const * msg,size_t msg_len,FpElemStr * c_str)30 EpidStatus HashSignCommitment(FiniteField* Fp, HashAlg hash_alg,
31 GroupPubKey const* pub_key,
32 SignCommitOutput const* commit_out,
33 void const* msg, size_t msg_len,
34 FpElemStr* c_str) {
35 EpidStatus sts = kEpidErr;
36 FfElement* c = NULL;
37
38 if (!Fp || !commit_out || (0 != msg_len && !msg) || !c_str) {
39 return kEpidBadArgErr;
40 }
41
42 do {
43 CommitValues values = {0};
44 sts = SetKeySpecificCommitValues(pub_key, &values);
45 BREAK_ON_EPID_ERROR(sts);
46
47 values.B = commit_out->B;
48 values.K = commit_out->K;
49 values.T = commit_out->T;
50 values.R1 = commit_out->R1;
51 values.R2 = commit_out->R2;
52
53 sts = NewFfElement(Fp, &c);
54 BREAK_ON_EPID_ERROR(sts);
55
56 // 5. The member computes t3 = Fp.hash(p || g1 || g2 || h1 || h2
57 // || w || B || K || T || R1 || R2).
58 // 6. The member computes c = Fp.hash(t3 || m).
59 sts = CalculateCommitmentHash(&values, Fp, hash_alg, msg, msg_len, c);
60 BREAK_ON_EPID_ERROR(sts);
61
62 sts = WriteFfElement(Fp, c, c_str, sizeof(*c_str));
63 BREAK_ON_EPID_ERROR(sts);
64
65 sts = kEpidNoErr;
66 } while (0);
67
68 DeleteFfElement(&c);
69
70 return sts;
71 }
72