1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
|
#include <string>
#include <memory>
#include <sstream>
#include <iostream>
#include <stdexcept>
#include <botan/botan.h>
#include <botan/filters.h>
#include <botan/eax.h>
using namespace Botan;
/**
Encrypt and decrypt small rows
*/
class Row_Encryptor
{
public:
Row_Encryptor(const std::string& passphrase,
RandomNumberGenerator& rng);
std::string encrypt(const std::string& input,
const MemoryRegion<byte>& salt);
std::string decrypt(const std::string& input,
const MemoryRegion<byte>& salt);
private:
Row_Encryptor(const Row_Encryptor&) {}
Row_Encryptor& operator=(const Row_Encryptor&) { return (*this); }
Pipe enc_pipe, dec_pipe;
EAX_Encryption* eax_enc; // owned by enc_pipe
EAX_Decryption* eax_dec; // owned by dec_pipe;
};
Row_Encryptor::Row_Encryptor(const std::string& passphrase,
RandomNumberGenerator& rng)
{
std::auto_ptr<S2K> s2k(get_s2k("PBKDF2(SHA-160)"));
s2k->set_iterations(10000);
s2k->new_random_salt(rng, 10); // 10 bytes == 80 bits
SecureVector<byte> key = s2k->derive_key(32, passphrase).bits_of();
/*
Save pointers to the EAX objects so we can change the IV as needed
*/
Algorithm_Factory& af = global_state().algorithm_factory();
const BlockCipher* proto = af.prototype_block_cipher("Serpent");
if(!proto)
throw std::runtime_error("Could not get a Serpent proto object");
enc_pipe.append(eax_enc = new EAX_Encryption(proto->clone()));
dec_pipe.append(eax_dec = new EAX_Decryption(proto->clone()));
eax_enc->set_key(key);
eax_dec->set_key(key);
}
std::string Row_Encryptor::encrypt(const std::string& input,
const MemoryRegion<byte>& salt)
{
eax_enc->set_iv(salt);
enc_pipe.start_msg();
enc_pipe.write(input);
enc_pipe.end_msg();
return enc_pipe.read_all_as_string(Pipe::LAST_MESSAGE);
}
std::string Row_Encryptor::decrypt(const std::string& input,
const MemoryRegion<byte>& salt)
{
eax_dec->set_iv(salt);
dec_pipe.start_msg();
dec_pipe.write(input);
dec_pipe.end_msg();
return dec_pipe.read_all_as_string(Pipe::LAST_MESSAGE);
}
/*************************
Test code follows:
*/
#include <botan/loadstor.h>
int main()
{
LibraryInitializer init;
AutoSeeded_RNG rng;
Row_Encryptor encryptor("secret passphrase", rng);
std::vector<std::string> original_inputs;
for(u32bit i = 0; i != 15000; ++i)
{
std::ostringstream out;
// This will actually generate variable length inputs (when
// there are leading 0s, which are skipped), which is good
// since it assures performance is OK across a mix of lengths
// TODO: Maybe randomize the length slightly?
for(u32bit j = 0; j != 32; ++j)
out << std::hex << (int)rng.next_byte();
original_inputs.push_back(out.str());
}
std::vector<std::string> encrypted_values;
MemoryVector<byte> salt(4); // keep out of loop to avoid excessive dynamic allocation
for(u32bit i = 0; i != original_inputs.size(); ++i)
{
std::string input = original_inputs[i];
store_le(i, salt);
encrypted_values.push_back(encryptor.encrypt(input, salt));
}
for(u32bit i = 0; i != encrypted_values.size(); ++i)
{
std::string ciphertext = encrypted_values[i];
store_le(i, salt); // NOTE: same salt value as previous loop (index value)
std::string output = encryptor.decrypt(ciphertext, salt);
if(output != original_inputs[i])
std::cout << "BOOM " << i << "\n";
}
}
|
