/src/botan/src/lib/hash/comb4p/comb4p.cpp
Line | Count | Source (jump to first uncovered line) |
1 | | /* |
2 | | * Comb4P hash combiner |
3 | | * (C) 2010 Jack Lloyd |
4 | | * |
5 | | * Botan is released under the Simplified BSD License (see license.txt) |
6 | | */ |
7 | | |
8 | | #include <botan/comb4p.h> |
9 | | #include <botan/exceptn.h> |
10 | | |
11 | | namespace Botan { |
12 | | |
13 | | namespace { |
14 | | |
15 | | void comb4p_round(secure_vector<uint8_t>& out, |
16 | | const secure_vector<uint8_t>& in, |
17 | | uint8_t round_no, |
18 | | HashFunction& h1, |
19 | | HashFunction& h2) |
20 | 0 | { |
21 | 0 | h1.update(round_no); |
22 | 0 | h2.update(round_no); |
23 | 0 |
|
24 | 0 | h1.update(in.data(), in.size()); |
25 | 0 | h2.update(in.data(), in.size()); |
26 | 0 |
|
27 | 0 | secure_vector<uint8_t> h_buf = h1.final(); |
28 | 0 | xor_buf(out.data(), h_buf.data(), std::min(out.size(), h_buf.size())); |
29 | 0 |
|
30 | 0 | h_buf = h2.final(); |
31 | 0 | xor_buf(out.data(), h_buf.data(), std::min(out.size(), h_buf.size())); |
32 | 0 | } |
33 | | |
34 | | } |
35 | | |
36 | | Comb4P::Comb4P(HashFunction* h1, HashFunction* h2) : |
37 | | m_hash1(h1), m_hash2(h2) |
38 | 0 | { |
39 | 0 | if(m_hash1->name() == m_hash2->name()) |
40 | 0 | throw Invalid_Argument("Comb4P: Must use two distinct hashes"); |
41 | 0 | |
42 | 0 | if(m_hash1->output_length() != m_hash2->output_length()) |
43 | 0 | throw Invalid_Argument("Comb4P: Incompatible hashes " + |
44 | 0 | m_hash1->name() + " and " + |
45 | 0 | m_hash2->name()); |
46 | 0 | |
47 | 0 | clear(); |
48 | 0 | } |
49 | | |
50 | | size_t Comb4P::hash_block_size() const |
51 | 0 | { |
52 | 0 | if(m_hash1->hash_block_size() == m_hash2->hash_block_size()) |
53 | 0 | return m_hash1->hash_block_size(); |
54 | 0 | |
55 | 0 | /* |
56 | 0 | * Return LCM of the block sizes? This would probably be OK for |
57 | 0 | * HMAC, which is the main thing relying on knowing the block size. |
58 | 0 | */ |
59 | 0 | return 0; |
60 | 0 | } |
61 | | |
62 | | void Comb4P::clear() |
63 | 0 | { |
64 | 0 | m_hash1->clear(); |
65 | 0 | m_hash2->clear(); |
66 | 0 |
|
67 | 0 | // Prep for processing next message, if any |
68 | 0 | m_hash1->update(0); |
69 | 0 | m_hash2->update(0); |
70 | 0 | } |
71 | | |
72 | | std::unique_ptr<HashFunction> Comb4P::copy_state() const |
73 | 0 | { |
74 | 0 | std::unique_ptr<Comb4P> copy(new Comb4P); |
75 | 0 | copy->m_hash1 = m_hash1->copy_state(); |
76 | 0 | copy->m_hash2 = m_hash2->copy_state(); |
77 | 0 | // work around GCC 4.8 bug |
78 | 0 | return std::unique_ptr<HashFunction>(copy.release()); |
79 | 0 | } |
80 | | |
81 | | void Comb4P::add_data(const uint8_t input[], size_t length) |
82 | 0 | { |
83 | 0 | m_hash1->update(input, length); |
84 | 0 | m_hash2->update(input, length); |
85 | 0 | } |
86 | | |
87 | | void Comb4P::final_result(uint8_t out[]) |
88 | 0 | { |
89 | 0 | secure_vector<uint8_t> h1 = m_hash1->final(); |
90 | 0 | secure_vector<uint8_t> h2 = m_hash2->final(); |
91 | 0 |
|
92 | 0 | // First round |
93 | 0 | xor_buf(h1.data(), h2.data(), std::min(h1.size(), h2.size())); |
94 | 0 |
|
95 | 0 | // Second round |
96 | 0 | comb4p_round(h2, h1, 1, *m_hash1, *m_hash2); |
97 | 0 |
|
98 | 0 | // Third round |
99 | 0 | comb4p_round(h1, h2, 2, *m_hash1, *m_hash2); |
100 | 0 |
|
101 | 0 | copy_mem(out , h1.data(), h1.size()); |
102 | 0 | copy_mem(out + h1.size(), h2.data(), h2.size()); |
103 | 0 |
|
104 | 0 | // Prep for processing next message, if any |
105 | 0 | m_hash1->update(0); |
106 | 0 | m_hash2->update(0); |
107 | 0 | } |
108 | | |
109 | | } |
110 | | |