Coverage Report

Created: 2021-02-21 07:20

/src/botan/src/lib/pubkey/ed25519/ed25519.cpp
Line
Count
Source (jump to first uncovered line)
1
/*
2
* Ed25519
3
* (C) 2017 Ribose Inc
4
*
5
* Based on the public domain code from SUPERCOP ref10 by
6
* Peter Schwabe, Daniel J. Bernstein, Niels Duif, Tanja Lange, Bo-Yin Yang
7
*
8
* Botan is released under the Simplified BSD License (see license.txt)
9
*/
10
11
#include <botan/ed25519.h>
12
#include <botan/internal/ed25519_internal.h>
13
#include <botan/internal/sha2_64.h>
14
#include <botan/rng.h>
15
16
namespace Botan {
17
18
void ed25519_gen_keypair(uint8_t* pk, uint8_t* sk, const uint8_t seed[32])
19
2
   {
20
2
   uint8_t az[64];
21
22
2
   SHA_512 sha;
23
2
   sha.update(seed, 32);
24
2
   sha.final(az);
25
2
   az[0] &= 248;
26
2
   az[31] &= 63;
27
2
   az[31] |= 64;
28
29
2
   ge_scalarmult_base(pk, az);
30
31
   // todo copy_mem
32
2
   copy_mem(sk, seed, 32);
33
2
   copy_mem(sk + 32, pk, 32);
34
2
   }
35
36
void ed25519_sign(uint8_t sig[64],
37
                  const uint8_t m[], size_t mlen,
38
                  const uint8_t sk[64],
39
                  const uint8_t domain_sep[], size_t domain_sep_len)
40
0
   {
41
0
   uint8_t az[64];
42
0
   uint8_t nonce[64];
43
0
   uint8_t hram[64];
44
45
0
   SHA_512 sha;
46
47
0
   sha.update(sk, 32);
48
0
   sha.final(az);
49
0
   az[0] &= 248;
50
0
   az[31] &= 63;
51
0
   az[31] |= 64;
52
53
0
   sha.update(domain_sep, domain_sep_len);
54
0
   sha.update(az + 32, 32);
55
0
   sha.update(m, mlen);
56
0
   sha.final(nonce);
57
58
0
   sc_reduce(nonce);
59
0
   ge_scalarmult_base(sig, nonce);
60
61
0
   sha.update(domain_sep, domain_sep_len);
62
0
   sha.update(sig, 32);
63
0
   sha.update(sk + 32, 32);
64
0
   sha.update(m, mlen);
65
0
   sha.final(hram);
66
67
0
   sc_reduce(hram);
68
0
   sc_muladd(sig + 32, hram, az, nonce);
69
0
   }
70
71
bool ed25519_verify(const uint8_t* m, size_t mlen,
72
                    const uint8_t sig[64],
73
                    const uint8_t* pk,
74
                    const uint8_t domain_sep[], size_t domain_sep_len)
75
94
   {
76
94
   uint8_t h[64];
77
94
   uint8_t rcheck[32];
78
94
   ge_p3 A;
79
94
   SHA_512 sha;
80
81
94
   if(sig[63] & 224)
82
5
      {
83
5
      return false;
84
5
      }
85
89
   if(ge_frombytes_negate_vartime(&A, pk) != 0)
86
2
      {
87
2
      return false;
88
2
      }
89
90
87
   sha.update(domain_sep, domain_sep_len);
91
87
   sha.update(sig, 32);
92
87
   sha.update(pk, 32);
93
87
   sha.update(m, mlen);
94
87
   sha.final(h);
95
87
   sc_reduce(h);
96
97
87
   ge_double_scalarmult_vartime(rcheck, h, &A, sig + 32);
98
99
87
   return constant_time_compare(rcheck, sig, 32);
100
87
   }
101
102
}