aboutsummaryrefslogtreecommitdiffstatshomepage
path: root/utils/decrypt_block.cpp
blob: 1337d555bbb21e49e83be4d08461b67417b5ca37 (plain) (blame)
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
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
// Copyright (c) 2015 Egor Tensin <Egor.Tensin@gmail.com>
// This file is part of the "AES tools" project.
// For details, see https://github.com/egor-tensin/aes-tools.
// Distributed under the MIT License.

#include "block_cmd_parser.hpp"
#include "block_dumper.hpp"
#include "block_input.hpp"

#include <aesxx/all.hpp>

#include <boost/program_options.hpp>

#include <exception>
#include <iostream>
#include <stdexcept>
#include <string>

namespace
{
    template <aes::Algorithm algorithm, aes::Mode mode>
    void decrypt_with_mode(
        const Input& input,
        bool verbose = false)
    {
        typename aes::Types<algorithm>::Block iv;

        if (aes::ModeRequiresInitVector<mode>())
        {
            aes::from_string<algorithm>(iv, input.iv);
            if (verbose)
                dump_iv<algorithm>(iv);
        }

        typename aes::Types<algorithm>::Key key;
        aes::from_string<algorithm>(key, input.key);
        if (verbose)
            dump_key<algorithm>(key);

        aes::DecryptWrapper<algorithm, mode> decrypt(key, iv);
        if (verbose)
            dump_wrapper<algorithm, mode>(decrypt);

        for (const auto& block : input.blocks)
        {
            typename aes::Types<algorithm>::Block ciphertext, plaintext;
            aes::from_string<algorithm>(ciphertext, block);

            decrypt.decrypt_block(ciphertext, plaintext);

            if (verbose)
            {
                dump_ciphertext<algorithm>(ciphertext);
                dump_plaintext<algorithm>(plaintext);
                dump_next_iv<algorithm, mode>(decrypt);
            }
            else
            {
                std::cout << aes::to_string<algorithm>(plaintext) << '\n';
            }
        }
    }

    template <aes::Algorithm algorithm>
    void decrypt_with_algorithm(
        aes::Mode mode,
        const Input& input,
        bool verbose = false)
    {
        switch (mode)
        {
            case AES_ECB:
                decrypt_with_mode<algorithm, AES_ECB>(input, verbose);
                break;

            case AES_CBC:
                decrypt_with_mode<algorithm, AES_CBC>(input, verbose);
                break;

            case AES_CFB:
                decrypt_with_mode<algorithm, AES_CFB>(input, verbose);
                break;

            case AES_OFB:
                decrypt_with_mode<algorithm, AES_OFB>(input, verbose);
                break;

            case AES_CTR:
                decrypt_with_mode<algorithm, AES_CTR>(input, verbose);
                break;

            default:
                throw std::runtime_error("the selected mode of operation is not implemented");
                break;
        }
    }

    void decrypt_using_cxx_api(
        aes::Algorithm algorithm,
        aes::Mode mode,
        const Input& input,
        bool verbose = false)
    {
        switch (algorithm)
        {
            case AES_AES128:
                decrypt_with_algorithm<AES_AES128>(mode, input, verbose);
                break;

            case AES_AES192:
                decrypt_with_algorithm<AES_AES192>(mode, input, verbose);
                break;

            case AES_AES256:
                decrypt_with_algorithm<AES_AES256>(mode, input, verbose);
                break;

            default:
                throw std::runtime_error("the selected algorithm is not implemented");
                break;
        }
    }

    void decrypt_using_particular_box(
        aes::Box& box,
        const std::vector<std::string>& blocks)
    {
        for (const auto& block : blocks)
        {
            aes::Box::Block ciphertext;
            box.parse_block(ciphertext, block);

            aes::Box::Block plaintext;
            box.decrypt_block(ciphertext, plaintext);
            std::cout << box.format_block(plaintext) << '\n';
        }
    }

    void decrypt_using_boxes(
        aes::Algorithm algorithm,
        aes::Mode mode,
        const Input& input)
    {
        aes::Box::Key key;
        aes::Box::parse_key(key, algorithm, input.key);

        if (aes::mode_requires_init_vector(mode))
        {
            aes::Box::Block iv;
            aes::Box::parse_block(iv, algorithm, input.iv);
            aes::Box box{algorithm, key, mode, iv};

            decrypt_using_particular_box(box, input.blocks);
        }
        else
        {
            aes::Box box{algorithm, key};
            decrypt_using_particular_box(box, input.blocks);
        }
    }
}

int main(int argc, char** argv)
{
    try
    {
        BlockSettings settings{argv[0]};

        try
        {
            settings.parse(argc, argv);
        }
        catch (const boost::program_options::error& e)
        {
            settings.usage_error(e);
            return 1;
        }

        if (settings.exit_with_usage)
        {
            settings.usage();
            return 0;
        }

        for (const auto& input : settings.inputs)
        {
            if (settings.use_boxes)
            {
                decrypt_using_boxes(
                    settings.algorithm,
                    settings.mode,
                    input);
            }
            else
            {
                decrypt_using_cxx_api(
                    settings.algorithm,
                    settings.mode,
                    input,
                    settings.verbose);
            }
        }
    }
    catch (const aes::Error& e)
    {
        std::cerr << e;
        return 1;
    }
    catch (const std::exception& e)
    {
        std::cerr << e.what() << "\n";
        return 1;
    }
    return 0;
}