Botan  2.11.0
Crypto and TLS for C++11
emsa.h
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1 /*
2 * EMSA Classes
3 * (C) 1999-2007 Jack Lloyd
4 *
5 * Botan is released under the Simplified BSD License (see license.txt)
6 */
7 
8 #ifndef BOTAN_PUBKEY_EMSA_H_
9 #define BOTAN_PUBKEY_EMSA_H_
10 
11 #include <botan/secmem.h>
12 #include <botan/alg_id.h>
13 #include <string>
14 
15 namespace Botan {
16 
17 class Private_Key;
18 class RandomNumberGenerator;
19 
20 /**
21 * EMSA, from IEEE 1363s Encoding Method for Signatures, Appendix
22 *
23 * Any way of encoding/padding signatures
24 */
26  {
27  public:
28  virtual ~EMSA() = default;
29 
30  /**
31  * Add more data to the signature computation
32  * @param input some data
33  * @param length length of input in bytes
34  */
35  virtual void update(const uint8_t input[], size_t length) = 0;
36 
37  /**
38  * @return raw hash
39  */
40  virtual secure_vector<uint8_t> raw_data() = 0;
41 
42  /**
43  * Return the encoding of a message
44  * @param msg the result of raw_data()
45  * @param output_bits the desired output bit size
46  * @param rng a random number generator
47  * @return encoded signature
48  */
49  virtual secure_vector<uint8_t> encoding_of(const secure_vector<uint8_t>& msg,
50  size_t output_bits,
51  RandomNumberGenerator& rng) = 0;
52 
53  /**
54  * Verify the encoding
55  * @param coded the received (coded) message representative
56  * @param raw the computed (local, uncoded) message representative
57  * @param key_bits the size of the key in bits
58  * @return true if coded is a valid encoding of raw, otherwise false
59  */
60  virtual bool verify(const secure_vector<uint8_t>& coded,
61  const secure_vector<uint8_t>& raw,
62  size_t key_bits) = 0;
63 
64  /**
65  * Prepare sig_algo for use in choose_sig_format for x509 certs
66  *
67  * @param key used for checking compatibility with the encoding scheme
68  * @param cert_hash_name is checked to equal the hash for the encoding
69  * @return algorithm identifier to signatures created using this key,
70  * padding method and hash.
71  */
72  virtual AlgorithmIdentifier config_for_x509(const Private_Key& key,
73  const std::string& cert_hash_name) const;
74 
75  /**
76  * @return a new object representing the same encoding method as *this
77  */
78  virtual EMSA* clone() = 0;
79 
80  /**
81  * @return the SCAN name of the encoding/padding scheme
82  */
83  virtual std::string name() const = 0;
84  };
85 
86 /**
87 * Factory method for EMSA (message-encoding methods for signatures
88 * with appendix) objects
89 * @param algo_spec the name of the EMSA to create
90 * @return pointer to newly allocated object of that type
91 */
92 BOTAN_PUBLIC_API(2,0) EMSA* get_emsa(const std::string& algo_spec);
93 
94 /**
95 * Returns the hash function used in the given EMSA scheme
96 * If the hash function is not specified or not understood,
97 * returns "SHA-512"
98 * @param algo_spec the name of the EMSA
99 * @return hash function used in the given EMSA scheme
100 */
101 BOTAN_PUBLIC_API(2,0) std::string hash_for_emsa(const std::string& algo_spec);
102 
103 }
104 
105 #endif
#define BOTAN_PUBLIC_API(maj, min)
Definition: compiler.h:31
Definition: bigint.h:1136
std::string name
std::string hash_for_emsa(const std::string &algo_spec)
Definition: emsa.cpp:189
Definition: alg_id.cpp:13
int(* update)(CTX *, const void *, CC_LONG len)
EMSA * get_emsa(const std::string &algo_spec)
Definition: emsa.cpp:44
std::vector< T, secure_allocator< T > > secure_vector
Definition: secmem.h:65