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
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
|
/*
* XMSS WOTS Private Key
* (C) 2016 Matthias Gierlings
*
* Botan is released under the Simplified BSD License (see license.txt)
**/
#ifndef BOTAN_XMSS_WOTS_PRIVATEKEY_H_
#define BOTAN_XMSS_WOTS_PRIVATEKEY_H_
#include <cstddef>
#include <memory>
#include <botan/alg_id.h>
#include <botan/exceptn.h>
#include <botan/pk_keys.h>
#include <botan/types.h>
#include <botan/xmss_wots_parameters.h>
#include <botan/xmss_address.h>
#include <botan/xmss_wots_publickey.h>
namespace Botan {
/** A Winternitz One Time Signature private key for use with Extended Hash-Based
* Signatures.
**/
class BOTAN_PUBLIC_API(2,0) XMSS_WOTS_PrivateKey : public virtual XMSS_WOTS_PublicKey,
public virtual Private_Key
{
public:
/**
* Creates a WOTS private key for the chosen XMSS WOTS signature method.
* Members need to be initialized manually.
*
* @param oid Identifier for the selected signature method.
**/
XMSS_WOTS_PrivateKey(XMSS_WOTS_Parameters::ots_algorithm_t oid)
: XMSS_WOTS_PublicKey(oid)
{}
/**
* Creates a WOTS private key for the chosen XMSS WOTS signature method.
*
* @param oid Identifier for the selected signature method.
* @param rng A random number generator to use for key generation.
**/
XMSS_WOTS_PrivateKey(XMSS_WOTS_Parameters::ots_algorithm_t oid,
RandomNumberGenerator& rng)
: XMSS_WOTS_PublicKey(oid, rng),
m_private_seed(rng.random_vec(m_wots_params.element_size()))
{
set_key_data(generate(m_private_seed));
}
/**
* Constructs a WOTS private key. Chains will be generated on demand
* applying a hash function to a unique value generated from a secret
* seed and a counter. The secret seed of length n, will be
* automatically generated using AutoSeeded_RNG(). "n" equals
* the element size of the chosen WOTS security parameter set.
*
* @param oid Identifier for the selected signature method.
* @param public_seed A public seed used for the pseudo random generation
* of public keys derived from this private key.
* @param rng A random number generator to use for key generation.
**/
XMSS_WOTS_PrivateKey(XMSS_WOTS_Parameters::ots_algorithm_t oid,
const secure_vector<uint8_t>& public_seed,
RandomNumberGenerator &rng)
: XMSS_WOTS_PublicKey(oid, public_seed),
m_private_seed(rng.random_vec(m_wots_params.element_size()))
{
set_key_data(generate(m_private_seed));
}
/**
* Constructs a WOTS private key. Chains will be generated on demand
* applying a hash function to a unique value generated from a secret
* seed and a counter. The secret seed of length n, will be
* automatically generated using AutoSeeded_RNG(). "n" equals
* the element size of the chosen WOTS security parameter set.
*
* @param oid Identifier for the selected signature method.
* @param public_seed A public seed used for the pseudo random generation
* of public keys derived from this private key.
**/
XMSS_WOTS_PrivateKey(XMSS_WOTS_Parameters::ots_algorithm_t oid,
const secure_vector<uint8_t>& public_seed)
: XMSS_WOTS_PublicKey(oid, public_seed)
{}
/**
* Constructs a WOTS private key. Chains will be generated on demand
* applying a hash function to a unique value generated from the
* secret seed and a counter.
*
* @param oid Identifier for the selected signature method.
* @param public_seed A public seed used for the pseudo random generation
* of public keys derived from this private key.
* @param private_seed A secret uniformly random n-byte value.
**/
XMSS_WOTS_PrivateKey(XMSS_WOTS_Parameters::ots_algorithm_t oid,
const secure_vector<uint8_t>& public_seed,
const secure_vector<uint8_t>& private_seed)
: XMSS_WOTS_PublicKey(oid, public_seed),
m_private_seed(private_seed)
{
set_key_data(generate(private_seed));
}
/**
* Retrieves the i-th WOTS private key using pseudo random key
* (re-)generation.
*
* @param i Index of the key to retrieve.
*
* @return WOTS secret key.
**/
wots_keysig_t operator[](size_t i)
{
secure_vector<uint8_t> idx_bytes;
XMSS_Tools::concat(idx_bytes, i, m_wots_params.element_size());
m_hash.h(idx_bytes, m_private_seed, idx_bytes);
return generate(idx_bytes);
}
/**
* Retrieves the i-th WOTS private key using pseudo random key
* (re-)generation.
*
* @param adrs The address of the key to retrieve.
*
* @return WOTS secret key.
**/
wots_keysig_t operator[](const XMSS_Address& adrs)
{
secure_vector<uint8_t> result;
m_hash.prf(result, m_private_seed, adrs.bytes());
return generate(result);
}
wots_keysig_t generate_private_key(const secure_vector<uint8_t>& priv_seed);
/**
* Algorithm 4: "WOTS_genPK"
* Generates a Winternitz One Time Signature+ (WOTS+) Public Key from a
* given private key.
*
* @param adrs Hash function address encoding the address of the WOTS+
* key pair within a greater structure.
*
* @return A XMSS_WOTS_PublicKey.
**/
XMSS_WOTS_PublicKey generate_public_key(XMSS_Address& adrs);
/**
* Algorithm 4: "WOTS_genPK"
* Initializes a Winternitz One Time Signature+ (WOTS+) Public Key's
* key_data() member, with data derived from in_key_data using the
* WOTS chaining function.
*
* @param[out] pub_key Public key to initialize key_data() member on.
* @param in_key_data Input key material from private key used for
* public key generation.
* @param adrs Hash function address encoding the address of
* the WOTS+ key pair within a greater structure.
**/
void generate_public_key(XMSS_WOTS_PublicKey& pub_key,
wots_keysig_t&& in_key_data,
XMSS_Address& adrs);
/**
* Algorithm 5: "WOTS_sign"
* Generates a signature from a private key and a message.
*
* @param msg A message to sign.
* @param adrs An OTS hash address identifying the WOTS+ key pair
* used for signing.
*
* @return signature for msg.
**/
wots_keysig_t sign(const secure_vector<uint8_t>& msg,
XMSS_Address& adrs);
/**
* Retrieves the secret seed used to generate WOTS+ chains. The seed
* should be a uniformly random n-byte value.
*
* @return secret seed.
**/
const secure_vector<uint8_t>& private_seed() const
{
return m_private_seed;
}
/**
* Sets the secret seed used to generate WOTS+ chains. The seed
* should be a uniformly random n-byte value.
*
* @param private_seed Uniformly random n-byte value.
**/
void set_private_seed(const secure_vector<uint8_t>& private_seed)
{
m_private_seed = private_seed;
}
/**
* Sets the secret seed used to generate WOTS+ chains. The seed
* should be a uniformly random n-byte value.
*
* @param private_seed Uniformly random n-byte value.
**/
void set_private_seed(secure_vector<uint8_t>&& private_seed)
{
m_private_seed = std::move(private_seed);
}
virtual AlgorithmIdentifier
pkcs8_algorithm_identifier() const override
{
throw Not_Implemented("No AlgorithmIdentifier available for XMSS-WOTS.");
}
virtual std::unique_ptr<PK_Ops::Signature>
create_signature_op(RandomNumberGenerator&,
const std::string&,
const std::string& provider) const override;
virtual secure_vector<uint8_t> private_key_bits() const override
{
throw Not_Implemented("No PKCS8 key format defined for XMSS-WOTS.");
}
private:
/**
* Algorithm 3: "Generating a WOTS+ Private Key".
* Generates a private key.
*
* @param private_seed Uniformly random n-byte value.
*
* @returns a vector of length key_size() of vectors of n bytes length
* containing uniformly random data.
**/
wots_keysig_t generate(const secure_vector<uint8_t>& private_seed);
secure_vector<uint8_t> m_private_seed;
};
}
#endif
|
