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crypto_sym.hpp
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1 //*********************************************************************/
2 // dar - disk archive - a backup/restoration program
3 // Copyright (C) 2002-2020 Denis Corbin
4 //
5 // This program is free software; you can redistribute it and/or
6 // modify it under the terms of the GNU General Public License
7 // as published by the Free Software Foundation; either version 2
8 // of the License, or (at your option) any later version.
9 //
10 // This program is distributed in the hope that it will be useful,
11 // but WITHOUT ANY WARRANTY; without even the implied warranty of
12 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 // GNU General Public License for more details.
14 //
15 // You should have received a copy of the GNU General Public License
16 // along with this program; if not, write to the Free Software
17 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
18 //
19 // to contact the author : http://dar.linux.free.fr/email.html
20 /*********************************************************************/
21
25
26 #ifndef CRYPTO_SYM_HPP
27 #define CRYPTO_SYM_HPP
28
29 extern "C"
30 {
31 #if HAVE_GCRYPT_H
32 #ifndef GCRYPT_NO_DEPRECATED
33 #define GCRYPT_NO_DEPRECATED
34 #endif
35 #include <gcrypt.h>
36 #endif
37 }
38
39 #include "../my_config.h"
40 #include <string>
41
42 #include "tronconneuse.hpp"
43 #include "secu_string.hpp"
44 #include "crypto.hpp"
45 #include "archive_aux.hpp"
46
47 namespace libdar
48 {
49
52
53 inline bool crypto_min_ver_libgcrypt_no_bug()
54 {
55 #if CRYPTO_AVAILABLE
56 return gcry_check_version(MIN_VERSION_GCRYPT_HASH_BUG);
57 #else
58 return true;
59 #endif
60 }
61
63
64 class crypto_sym : public tronconneuse
65 {
66 public:
67 crypto_sym(U_32 block_size,
68 const secu_string & password,
69 generic_file & encrypted_side,
70 bool no_initial_shift,
71 const archive_version & reading_ver,
72 crypto_algo algo,
73 const std::string & salt, //< not used is use_pkcs5 below is not set
74 infinint iteration_count, //< not used if use_pkcs5 is not set
75 hash_algo kdf_hash, //< not used if use_pkcs5 is not set
76 bool use_pkcs5); //< must be set to true when password is human defined to add a key derivation
77 crypto_sym(const crypto_sym & ref) = delete;
78 crypto_sym(crypto_sym && ref) = delete;
79 crypto_sym & operator = (const crypto_sym & ref) = delete;
80 crypto_sym & operator = (crypto_sym && ref) = delete;
81 ~crypto_sym() { detruit(); };
82
84 static size_t max_key_len(crypto_algo algo);
85
87 static size_t max_key_len_libdar(crypto_algo algo);
88
90 static bool is_a_strong_password(crypto_algo algo, const secu_string & password);
91
93 static std::string generate_salt(U_I size);
94
95 protected:
96 virtual U_32 encrypted_block_size_for(U_32 clear_block_size) override;
97 virtual U_32 clear_block_allocated_size_for(U_32 clear_block_size) override;
98 virtual U_32 encrypt_data(const infinint & block_num,
99 const char *clear_buf, const U_32 clear_size, const U_32 clear_allocated,
100 char *crypt_buf, U_32 crypt_size) override;
101 virtual U_32 decrypt_data(const infinint & block_num,
102 const char *crypt_buf, const U_32 crypt_size,
103 char *clear_buf, U_32 clear_size) override;
104
105 private:
106 #if CRYPTO_AVAILABLE
107 gcry_cipher_hd_t clef;
108 gcry_cipher_hd_t essiv_clef;
109 #endif
110 size_t algo_block_size;
111 unsigned char *ivec;
112 U_I algo_id;
113
114 void detruit();
115
117
119
120 #if CRYPTO_AVAILABLE
121 static void dar_set_essiv(const secu_string & key,
122 gcry_cipher_hd_t & IVkey,
123 const archive_version & ver,
124 crypto_algo main_cipher);
125
132 static void make_ivec(const infinint & ref,
133 unsigned char *ivec,
134 U_I size,
135 const gcry_cipher_hd_t & IVkey);
136
138 static secu_string pkcs5_pass2key(const secu_string & password,
139 const std::string & salt,
140 U_I iteration_count,
141 U_I hash_gcrypt,
142 U_I output_length);
143
145 static U_I get_algo_id(crypto_algo algo);
146 #endif
147
148 #ifdef LIBDAR_NO_OPTIMIZATION
149 static void self_test(void);
150 #endif
151 };
152
154
155 } // end of namespace
156
157 #endif
libdar::hash_algo
hash_algo
hashing algorithm available
Definition: archive_aux.hpp:63
libdar::crypto_sym::encrypted_block_size_for
virtual U_32 encrypted_block_size_for(U_32 clear_block_size) override
defines the size necessary to encrypt a given amount of clear data
tronconneuse.hpp
defines a block structured file.
libdar::crypto_sym::generate_salt
static std::string generate_salt(U_I size)
generates a random salt of given size
libdar::infinint
the arbitrary large positive integer class
Definition: real_infinint.hpp:62
libdar::tronconneuse::reading_ver
archive_version reading_ver
archive format we currently read
Definition: tronconneuse.hpp:217
libdar::crypto_sym::algo_id
U_I algo_id
algo ID in libgcrypt
Definition: crypto_sym.hpp:112
libdar::crypto_sym::clear_block_allocated_size_for
virtual U_32 clear_block_allocated_size_for(U_32 clear_block_size) override
it may be necessary by the inherited class have few more bytes allocated after the clear data given f...
libdar::archive_version
class archive_version manages the version of the archive format
Definition: archive_version.hpp:47
libdar::crypto_sym
symetrical strong encryption, interface to grypt library
Definition: crypto_sym.hpp:65
libdar::crypto_sym::decrypt_data
virtual U_32 decrypt_data(const infinint &block_num, const char *crypt_buf, const U_32 crypt_size, char *clear_buf, U_32 clear_size) override
this method decyphers data
libdar::tronconneuse::clear_block_size
U_32 clear_block_size
max amount of data that will be encrypted at once (must stay less than buf_size)
Definition: tronconneuse.hpp:201
secu_string.hpp
this file contains the definition of secu_string class, a std::string like class but allocated in sec...
archive_aux.hpp
set of datastructures used to interact with a catalogue object
libdar::crypto_sym::max_key_len
static size_t max_key_len(crypto_algo algo)
returns the max key length in octets for the given algorithm
libdar::generic_file
this is the interface class from which all other data transfer classes inherit
Definition: generic_file.hpp:77
libdar::crypto_sym::is_a_strong_password
static bool is_a_strong_password(crypto_algo algo, const secu_string &password)
check whether the given password is reported as strong in regard to the given cipher
libdar::crypto_sym::ivec
unsigned char * ivec
algo_block_size allocated in secure memory to be used as Initial Vector
Definition: crypto_sym.hpp:111
libdar::secu_string
class secu_string
Definition: secu_string.hpp:58
libdar::crypto_sym::algo_block_size
size_t algo_block_size
the block size of the algorithm (main key)
Definition: crypto_sym.hpp:110
libdar::crypto_algo
crypto_algo
the different cypher available for encryption (strong or weak)
Definition: crypto.hpp:50
libdar::tronconneuse
this is a partial implementation of the generic_file interface to cypher/decypher data block by block...
Definition: tronconneuse.hpp:59
libdar::crypto_sym::encrypt_data
virtual U_32 encrypt_data(const infinint &block_num, const char *clear_buf, const U_32 clear_size, const U_32 clear_allocated, char *crypt_buf, U_32 crypt_size) override
this method encrypts the clear data given
libdar::crypto_sym::max_key_len_libdar
static size_t max_key_len_libdar(crypto_algo algo)
returns the max key length in octets to use to compute a key from a user provided password
crypto.hpp
the crypto algoritm definition
libdar::tronconneuse::block_num
infinint block_num
block number we next read or write
Definition: tronconneuse.hpp:203
libdar
libdar namespace encapsulate all libdar symbols
Definition: archive.hpp:47