Botan 1.10.17

ossl_arc4.cpp
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1 /*
2 * OpenSSL ARC4
3 * (C) 1999-2007 Jack Lloyd
4 *
5 * Distributed under the terms of the Botan license
6 */
7
8 #include <botan/internal/openssl_engine.h>
9 #include <botan/parsing.h>
10 #include <openssl/opensslconf.h>
11 #if !defined(OPENSSL_NO_RC4)
12 #include <openssl/rc4.h>
13 #endif
14
15 namespace Botan {
16
17 #if !defined(OPENSSL_NO_RC4)
18 namespace {
19
20 /**
21 * ARC4 as implemented by OpenSSL
22 */
23 class ARC4_OpenSSL : public StreamCipher
24 {
25 public:
26 void clear() { std::memset(&state, 0, sizeof(state)); }
27 std::string name() const;
28 StreamCipher* clone() const { return new ARC4_OpenSSL(SKIP); }
29
30 Key_Length_Specification key_spec() const
31 {
32 return Key_Length_Specification(1, 32);
33 }
34
35
36 ARC4_OpenSSL(size_t s = 0) : SKIP(s) { clear(); }
37 ~ARC4_OpenSSL() { clear(); }
38 private:
39 void cipher(const byte[], byte[], size_t);
40 void key_schedule(const byte[], size_t);
41
42 const size_t SKIP;
43 RC4_KEY state;
44 };
45
46 /*
47 * Return the name of this type
48 */
49 std::string ARC4_OpenSSL::name() const
50 {
51 if(SKIP == 0) return "ARC4";
52 if(SKIP == 256) return "MARK-4";
53 else return "RC4_skip(" + to_string(SKIP) + ")";
54 }
55
56 /*
57 * ARC4 Key Schedule
58 */
59 void ARC4_OpenSSL::key_schedule(const byte key[], size_t length)
60 {
61 RC4_set_key(&state, length, key);
62 byte dummy = 0;
63 for(size_t i = 0; i != SKIP; ++i)
64 RC4(&state, 1, &dummy, &dummy);
65 }
66
67 /*
68 * ARC4 Encryption
69 */
70 void ARC4_OpenSSL::cipher(const byte in[], byte out[], size_t length)
71 {
72 RC4(&state, length, in, out);
73 }
74
75 }
76 #endif
77
78 /**
79 * Look for an OpenSSL-supported stream cipher (ARC4)
80 */
81 StreamCipher*
82 OpenSSL_Engine::find_stream_cipher(const SCAN_Name& request,
83 Algorithm_Factory&) const
84 {
85 #if !defined(OPENSSL_NO_RC4)
86 if(request.algo_name() == "ARC4")
87 return new ARC4_OpenSSL(request.arg_as_integer(0, 0));
88 if(request.algo_name() == "RC4_drop")
89 return new ARC4_OpenSSL(768);
90 #endif
91
92 return 0;
93 }
94
95 }
Botan::Algorithm_Factory
Definition: algo_factory.h:34
Botan::SCAN_Name::arg_as_integer
size_t arg_as_integer(size_t i, size_t def_value) const
Definition: scan_name.cpp:167
Botan::OpenSSL_Engine::find_stream_cipher
StreamCipher * find_stream_cipher(const SCAN_Name &, Algorithm_Factory &) const
Definition: ossl_arc4.cpp:82
Botan::byte
unsigned char byte
Definition: types.h:22
Botan
Definition: algo_base.h:14
Botan::SCAN_Name
Definition: scan_name.h:21
Botan::to_string
std::string to_string(u64bit n, size_t min_len)
Definition: parsing.cpp:42
Botan::SCAN_Name::algo_name
std::string algo_name() const
Definition: scan_name.h:37