6642806734

Committed 25 Oct 2023 03:40PM UTC coverage: 91.687% (+0.01%) from 91.677%

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Commit Message

Merge pull request #3770 from Rohde-Schwarz/feature/pubkey_create_another

Feature: `AsymmetricKey::generate_another()`

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89.09

/src/lib/pubkey/ecdsa/ecdsa.cpp

/*
* ECDSA implemenation
* (C) 2007 Manuel Hartl, FlexSecure GmbH
*     2007 Falko Strenzke, FlexSecure GmbH
*     2008-2010,2015,2016,2018 Jack Lloyd
*     2016 René Korthaus
*
* Botan is released under the Simplified BSD License (see license.txt)
*/

#include <botan/ecdsa.h>

#include <botan/reducer.h>
#include <botan/internal/keypair.h>
#include <botan/internal/pk_ops_impl.h>
#include <botan/internal/point_mul.h>

#if defined(BOTAN_HAS_RFC6979_GENERATOR)
   #include <botan/internal/rfc6979.h>
#endif

namespace Botan {

namespace {

EC_Point recover_ecdsa_public_key(
   const EC_Group& group, const std::vector<uint8_t>& msg, const BigInt& r, const BigInt& s, uint8_t v) {
   if(group.get_cofactor() != 1) {
      throw Invalid_Argument("ECDSA public key recovery only supported for prime order groups");
   }

   if(v >= 4) {
      throw Invalid_Argument("Unexpected v param for ECDSA public key recovery");
   }

   const BigInt& group_order = group.get_order();

   if(r <= 0 || r >= group_order || s <= 0 || s >= group_order) {
      throw Invalid_Argument("Out of range r/s cannot recover ECDSA public key");
   }

   const uint8_t y_odd = v % 2;
   const uint8_t add_order = v >> 1;
   const size_t p_bytes = group.get_p_bytes();

   try {
      const BigInt e = BigInt::from_bytes_with_max_bits(msg.data(), msg.size(), group.get_order_bits());
      const BigInt r_inv = group.inverse_mod_order(r);

      BigInt x = r + add_order * group_order;

      std::vector<uint8_t> X(p_bytes + 1);

      X[0] = 0x02 | y_odd;
      BigInt::encode_1363(&X[1], p_bytes, x);

      const EC_Point R = group.OS2ECP(X);

      if((R * group_order).is_zero() == false) {
         throw Decoding_Error("Unable to recover ECDSA public key");
      }

      // Compute r_inv * (s*R - eG)
      EC_Point_Multi_Point_Precompute RG_mul(R, group.get_base_point());
      const BigInt ne = group.mod_order(group_order - e);
      return r_inv * RG_mul.multi_exp(s, ne);
   } catch(...) {
      // continue on and throw
   }

   throw Decoding_Error("Failed to recover ECDSA public key from signature/msg pair");
}

}  // namespace

ECDSA_PublicKey::ECDSA_PublicKey(
   const EC_Group& group, const std::vector<uint8_t>& msg, const BigInt& r, const BigInt& s, uint8_t v) :
      EC_PublicKey(group, recover_ecdsa_public_key(group, msg, r, s, v)) {}

std::unique_ptr<Private_Key> ECDSA_PublicKey::generate_another(RandomNumberGenerator& rng) const {
   return std::make_unique<ECDSA_PrivateKey>(rng, domain());
}

uint8_t ECDSA_PublicKey::recovery_param(const std::vector<uint8_t>& msg, const BigInt& r, const BigInt& s) const {
   for(uint8_t v = 0; v != 4; ++v) {
      try {
         EC_Point R = recover_ecdsa_public_key(this->domain(), msg, r, s, v);

         if(R == this->public_point()) {
            return v;
         }
      } catch(Decoding_Error&) {
         // try the next v
      }
   }

   throw Internal_Error("Could not determine ECDSA recovery parameter");
}

std::unique_ptr<Public_Key> ECDSA_PrivateKey::public_key() const {
   return std::make_unique<ECDSA_PublicKey>(domain(), public_point());
}

bool ECDSA_PrivateKey::check_key(RandomNumberGenerator& rng, bool strong) const {
   if(!public_point().on_the_curve()) {
      return false;
   }

   if(!strong) {
      return true;
   }

   return KeyPair::signature_consistency_check(rng, *this, "SHA-256");
}

namespace {

/**
* ECDSA signature operation
*/
class ECDSA_Signature_Operation final : public PK_Ops::Signature_with_Hash {
   public:
      ECDSA_Signature_Operation(const ECDSA_PrivateKey& ecdsa, std::string_view padding, RandomNumberGenerator& rng) :
            PK_Ops::Signature_with_Hash(padding), m_group(ecdsa.domain()), m_x(ecdsa.private_value()) {
#if defined(BOTAN_HAS_RFC6979_GENERATOR)
         m_rfc6979 = std::make_unique<RFC6979_Nonce_Generator>(this->rfc6979_hash_function(), m_group.get_order(), m_x);
#endif

         m_b = m_group.random_scalar(rng);
         m_b_inv = m_group.inverse_mod_order(m_b);
      }

      size_t signature_length() const override { return 2 * m_group.get_order_bytes(); }

      secure_vector<uint8_t> raw_sign(const uint8_t msg[], size_t msg_len, RandomNumberGenerator& rng) override;

      AlgorithmIdentifier algorithm_identifier() const override;

   private:
      const EC_Group m_group;
      const BigInt m_x;

#if defined(BOTAN_HAS_RFC6979_GENERATOR)
      std::unique_ptr<RFC6979_Nonce_Generator> m_rfc6979;
#endif

      std::vector<BigInt> m_ws;

      BigInt m_b, m_b_inv;
};

AlgorithmIdentifier ECDSA_Signature_Operation::algorithm_identifier() const {
   const std::string full_name = "ECDSA/" + hash_function();
   const OID oid = OID::from_string(full_name);
   return AlgorithmIdentifier(oid, AlgorithmIdentifier::USE_EMPTY_PARAM);
}

secure_vector<uint8_t> ECDSA_Signature_Operation::raw_sign(const uint8_t msg[],
                                                           size_t msg_len,
                                                           RandomNumberGenerator& rng) {
   BigInt m = BigInt::from_bytes_with_max_bits(msg, msg_len, m_group.get_order_bits());

#if defined(BOTAN_HAS_RFC6979_GENERATOR)
   const BigInt k = m_rfc6979->nonce_for(m);
#else
   const BigInt k = m_group.random_scalar(rng);
#endif

   const BigInt r = m_group.mod_order(m_group.blinded_base_point_multiply_x(k, rng, m_ws));

   const BigInt k_inv = m_group.inverse_mod_order(k);

   /*
   * Blind the input message and compute x*r+m as (x*r*b + m*b)/b
   */
   m_b = m_group.square_mod_order(m_b);
   m_b_inv = m_group.square_mod_order(m_b_inv);

   m = m_group.multiply_mod_order(m_b, m_group.mod_order(m));
   const BigInt xr_m = m_group.mod_order(m_group.multiply_mod_order(m_x, m_b, r) + m);

   const BigInt s = m_group.multiply_mod_order(k_inv, xr_m, m_b_inv);

   // With overwhelming probability, a bug rather than actual zero r/s
   if(r.is_zero() || s.is_zero()) {
      throw Internal_Error("During ECDSA signature generated zero r/s");
   }

   return BigInt::encode_fixed_length_int_pair(r, s, m_group.get_order_bytes());
}

/**
* ECDSA verification operation
*/
class ECDSA_Verification_Operation final : public PK_Ops::Verification_with_Hash {
   public:
      ECDSA_Verification_Operation(const ECDSA_PublicKey& ecdsa, std::string_view padding) :
            PK_Ops::Verification_with_Hash(padding),
            m_group(ecdsa.domain()),
            m_gy_mul(m_group.get_base_point(), ecdsa.public_point()) {}

      ECDSA_Verification_Operation(const ECDSA_PublicKey& ecdsa, const AlgorithmIdentifier& alg_id) :
            PK_Ops::Verification_with_Hash(alg_id, "ECDSA", true),
            m_group(ecdsa.domain()),
            m_gy_mul(m_group.get_base_point(), ecdsa.public_point()) {}

      bool verify(const uint8_t msg[], size_t msg_len, const uint8_t sig[], size_t sig_len) override;

   private:
      const EC_Group m_group;
      const EC_Point_Multi_Point_Precompute m_gy_mul;
};

bool ECDSA_Verification_Operation::verify(const uint8_t msg[], size_t msg_len, const uint8_t sig[], size_t sig_len) {
   if(sig_len != m_group.get_order_bytes() * 2) {
      return false;
   }

   const BigInt e = BigInt::from_bytes_with_max_bits(msg, msg_len, m_group.get_order_bits());

   const BigInt r(sig, sig_len / 2);
   const BigInt s(sig + sig_len / 2, sig_len / 2);

   // Cannot be negative here since we just decoded from binary
   if(r.is_zero() || s.is_zero()) {
      return false;
   }

   if(r >= m_group.get_order() || s >= m_group.get_order()) {
      return false;
   }

   const BigInt w = m_group.inverse_mod_order(s);

   const BigInt u1 = m_group.multiply_mod_order(m_group.mod_order(e), w);
   const BigInt u2 = m_group.multiply_mod_order(r, w);
   const EC_Point R = m_gy_mul.multi_exp(u1, u2);

   if(R.is_zero()) {
      return false;
   }

   const BigInt v = m_group.mod_order(R.get_affine_x());
   return (v == r);
}

}  // namespace

std::unique_ptr<PK_Ops::Verification> ECDSA_PublicKey::create_verification_op(std::string_view params,
                                                                              std::string_view provider) const {
   if(provider == "base" || provider.empty()) {
      return std::make_unique<ECDSA_Verification_Operation>(*this, params);
   }

   throw Provider_Not_Found(algo_name(), provider);
}

std::unique_ptr<PK_Ops::Verification> ECDSA_PublicKey::create_x509_verification_op(
   const AlgorithmIdentifier& signature_algorithm, std::string_view provider) const {
   if(provider == "base" || provider.empty()) {
      return std::make_unique<ECDSA_Verification_Operation>(*this, signature_algorithm);
   }

   throw Provider_Not_Found(algo_name(), provider);
}

std::unique_ptr<PK_Ops::Signature> ECDSA_PrivateKey::create_signature_op(RandomNumberGenerator& rng,
                                                                         std::string_view params,
                                                                         std::string_view provider) const {
   if(provider == "base" || provider.empty()) {
      return std::make_unique<ECDSA_Signature_Operation>(*this, params, rng);
   }

   throw Provider_Not_Found(algo_name(), provider);
}

}  // namespace Botan

1	/*
2	* ECDSA implemenation
3	* (C) 2007 Manuel Hartl, FlexSecure GmbH
4	* 2007 Falko Strenzke, FlexSecure GmbH
5	* 2008-2010,2015,2016,2018 Jack Lloyd
6	* 2016 René Korthaus
7	*
8	* Botan is released under the Simplified BSD License (see license.txt)
9	*/
10
11	#include <botan/ecdsa.h>
12
13	#include <botan/reducer.h>
14	#include <botan/internal/keypair.h>
15	#include <botan/internal/pk_ops_impl.h>
16	#include <botan/internal/point_mul.h>
17
18	#if defined(BOTAN_HAS_RFC6979_GENERATOR)
19	#include <botan/internal/rfc6979.h>
20	#endif
21
22	namespace Botan {
23
24	namespace {
25
26	EC_Point recover_ecdsa_public_key(	20✔
27	const EC_Group& group, const std::vector<uint8_t>& msg, const BigInt& r, const BigInt& s, uint8_t v) {
28	if(group.get_cofactor() != 1) {	20✔
29	throw Invalid_Argument("ECDSA public key recovery only supported for prime order groups");	×
30	}
31
32	if(v >= 4) {	20✔
33	throw Invalid_Argument("Unexpected v param for ECDSA public key recovery");	×
34	}
35
36	const BigInt& group_order = group.get_order();	20✔
37
38	if(r <= 0 \|\| r >= group_order \|\| s <= 0 \|\| s >= group_order) {	80✔
39	throw Invalid_Argument("Out of range r/s cannot recover ECDSA public key");	×
40	}
41
42	const uint8_t y_odd = v % 2;	20✔
43	const uint8_t add_order = v >> 1;	20✔
44	const size_t p_bytes = group.get_p_bytes();	20✔
45
46	try {	20✔
47	const BigInt e = BigInt::from_bytes_with_max_bits(msg.data(), msg.size(), group.get_order_bits());	20✔
48	const BigInt r_inv = group.inverse_mod_order(r);	20✔
49
50	BigInt x = r + add_order * group_order;	20✔
51
52	std::vector<uint8_t> X(p_bytes + 1);	20✔
53
54	X[0] = 0x02 \| y_odd;	20✔
55	BigInt::encode_1363(&X[1], p_bytes, x);	20✔
56
57	const EC_Point R = group.OS2ECP(X);	20✔
58
59	if((R * group_order).is_zero() == false) {	20✔
60	throw Decoding_Error("Unable to recover ECDSA public key");	×
61	}
62
63	// Compute r_inv * (s*R - eG)
64	EC_Point_Multi_Point_Precompute RG_mul(R, group.get_base_point());	20✔
65	const BigInt ne = group.mod_order(group_order - e);	20✔
66	return r_inv * RG_mul.multi_exp(s, ne);	20✔
67	} catch(...) {	100✔
68	// continue on and throw
69	}	×
70
71	throw Decoding_Error("Failed to recover ECDSA public key from signature/msg pair");	×
72	}
73
74	} // namespace
75
76	ECDSA_PublicKey::ECDSA_PublicKey(	8✔
77	const EC_Group& group, const std::vector<uint8_t>& msg, const BigInt& r, const BigInt& s, uint8_t v) :	8✔
78	EC_PublicKey(group, recover_ecdsa_public_key(group, msg, r, s, v)) {}	8✔
79
80	std::unique_ptr<Private_Key> ECDSA_PublicKey::generate_another(RandomNumberGenerator& rng) const {	4✔
81	return std::make_unique<ECDSA_PrivateKey>(rng, domain());	8✔
82	}
83
84	uint8_t ECDSA_PublicKey::recovery_param(const std::vector<uint8_t>& msg, const BigInt& r, const BigInt& s) const {	8✔
85	for(uint8_t v = 0; v != 4; ++v) {	12✔
86	try {	12✔
87	EC_Point R = recover_ecdsa_public_key(this->domain(), msg, r, s, v);	12✔
88
89	if(R == this->public_point()) {	12✔
90	return v;	8✔
91	}
92	} catch(Decoding_Error&) {	12✔
93	// try the next v
94	}	×
95	}
96
97	throw Internal_Error("Could not determine ECDSA recovery parameter");	×
98	}
99
100	std::unique_ptr<Public_Key> ECDSA_PrivateKey::public_key() const {	200✔
101	return std::make_unique<ECDSA_PublicKey>(domain(), public_point());	200✔
102	}
103
104	bool ECDSA_PrivateKey::check_key(RandomNumberGenerator& rng, bool strong) const {	8✔
105	if(!public_point().on_the_curve()) {	8✔
106	return false;
107	}
108
109	if(!strong) {	8✔
110	return true;
111	}
112
113	return KeyPair::signature_consistency_check(rng, *this, "SHA-256");	7✔
114	}
115
116	namespace {
117
118	/**
119	* ECDSA signature operation
120	*/
121	class ECDSA_Signature_Operation final : public PK_Ops::Signature_with_Hash {	×
122	public:
123	ECDSA_Signature_Operation(const ECDSA_PrivateKey& ecdsa, std::string_view padding, RandomNumberGenerator& rng) :	394✔
124	PK_Ops::Signature_with_Hash(padding), m_group(ecdsa.domain()), m_x(ecdsa.private_value()) {	394✔
125	#if defined(BOTAN_HAS_RFC6979_GENERATOR)
126	m_rfc6979 = std::make_unique<RFC6979_Nonce_Generator>(this->rfc6979_hash_function(), m_group.get_order(), m_x);	394✔
127	#endif
128
129	m_b = m_group.random_scalar(rng);	788✔
130	m_b_inv = m_group.inverse_mod_order(m_b);	788✔
131	}	394✔
132
133	size_t signature_length() const override { return 2 * m_group.get_order_bytes(); }	108✔
134
135	secure_vector<uint8_t> raw_sign(const uint8_t msg[], size_t msg_len, RandomNumberGenerator& rng) override;
136
137	AlgorithmIdentifier algorithm_identifier() const override;
138
139	private:
140	const EC_Group m_group;
141	const BigInt m_x;
142
143	#if defined(BOTAN_HAS_RFC6979_GENERATOR)
144	std::unique_ptr<RFC6979_Nonce_Generator> m_rfc6979;
145	#endif
146
147	std::vector<BigInt> m_ws;
148
149	BigInt m_b, m_b_inv;
150	};
151
152	AlgorithmIdentifier ECDSA_Signature_Operation::algorithm_identifier() const {	62✔
153	const std::string full_name = "ECDSA/" + hash_function();	62✔
154	const OID oid = OID::from_string(full_name);	62✔
155	return AlgorithmIdentifier(oid, AlgorithmIdentifier::USE_EMPTY_PARAM);	62✔
156	}	62✔
157
158	secure_vector<uint8_t> ECDSA_Signature_Operation::raw_sign(const uint8_t msg[],	404✔
159	size_t msg_len,
160	RandomNumberGenerator& rng) {
161	BigInt m = BigInt::from_bytes_with_max_bits(msg, msg_len, m_group.get_order_bits());	404✔
162
163	#if defined(BOTAN_HAS_RFC6979_GENERATOR)
164	const BigInt k = m_rfc6979->nonce_for(m);	404✔
165	#else
166	const BigInt k = m_group.random_scalar(rng);
167	#endif
168
169	const BigInt r = m_group.mod_order(m_group.blinded_base_point_multiply_x(k, rng, m_ws));	404✔
170
171	const BigInt k_inv = m_group.inverse_mod_order(k);	404✔
172
173	/*
174	* Blind the input message and compute xr+m as (xrb + mb)/b
175	*/
176	m_b = m_group.square_mod_order(m_b);	404✔
177	m_b_inv = m_group.square_mod_order(m_b_inv);	404✔
178
179	m = m_group.multiply_mod_order(m_b, m_group.mod_order(m));	808✔
180	const BigInt xr_m = m_group.mod_order(m_group.multiply_mod_order(m_x, m_b, r) + m);	808✔
181
182	const BigInt s = m_group.multiply_mod_order(k_inv, xr_m, m_b_inv);	404✔
183
184	// With overwhelming probability, a bug rather than actual zero r/s
185	if(r.is_zero() \|\| s.is_zero()) {	808✔
186	throw Internal_Error("During ECDSA signature generated zero r/s");	×
187	}
188
189	return BigInt::encode_fixed_length_int_pair(r, s, m_group.get_order_bytes());	404✔
190	}	2,424✔
191
192	/**
193	* ECDSA verification operation
194	*/
195	class ECDSA_Verification_Operation final : public PK_Ops::Verification_with_Hash {	×
196	public:
197	ECDSA_Verification_Operation(const ECDSA_PublicKey& ecdsa, std::string_view padding) :	12,415✔
198	PK_Ops::Verification_with_Hash(padding),
199	m_group(ecdsa.domain()),	16,330✔
200	m_gy_mul(m_group.get_base_point(), ecdsa.public_point()) {}	12,415✔
201
202	ECDSA_Verification_Operation(const ECDSA_PublicKey& ecdsa, const AlgorithmIdentifier& alg_id) :	2,119✔
203	PK_Ops::Verification_with_Hash(alg_id, "ECDSA", true),
204	m_group(ecdsa.domain()),	4,216✔
205	m_gy_mul(m_group.get_base_point(), ecdsa.public_point()) {}	2,119✔
206
207	bool verify(const uint8_t msg[], size_t msg_len, const uint8_t sig[], size_t sig_len) override;
208
209	private:
210	const EC_Group m_group;
211	const EC_Point_Multi_Point_Precompute m_gy_mul;
212	};
213
214	bool ECDSA_Verification_Operation::verify(const uint8_t msg[], size_t msg_len, const uint8_t sig[], size_t sig_len) {	16,582✔
215	if(sig_len != m_group.get_order_bytes() * 2) {	16,582✔
216	return false;
217	}
218
219	const BigInt e = BigInt::from_bytes_with_max_bits(msg, msg_len, m_group.get_order_bits());	13,584✔
220
221	const BigInt r(sig, sig_len / 2);	13,584✔
222	const BigInt s(sig + sig_len / 2, sig_len / 2);	13,584✔
223
224	// Cannot be negative here since we just decoded from binary
225	if(r.is_zero() \|\| s.is_zero()) {	40,307✔
226	return false;	590✔
227	}
228
229	if(r >= m_group.get_order() \|\| s >= m_group.get_order()) {	12,994✔
230	return false;	664✔
231	}
232
233	const BigInt w = m_group.inverse_mod_order(s);	12,330✔
234
235	const BigInt u1 = m_group.multiply_mod_order(m_group.mod_order(e), w);	12,330✔
236	const BigInt u2 = m_group.multiply_mod_order(r, w);	12,330✔
237	const EC_Point R = m_gy_mul.multi_exp(u1, u2);	12,330✔
238
239	if(R.is_zero()) {	24,546✔
240	return false;
241	}
242
243	const BigInt v = m_group.mod_order(R.get_affine_x());	12,219✔
244	return (v == r);	12,219✔
245	}	94,324✔
246
247	} // namespace
248
249	std::unique_ptr<PK_Ops::Verification> ECDSA_PublicKey::create_verification_op(std::string_view params,	48,928✔
250	std::string_view provider) const {
251	if(provider == "base" \|\| provider.empty()) {	61,107✔
252	return std::make_unique<ECDSA_Verification_Operation>(*this, params);	12,415✔
253	}
254
255	throw Provider_Not_Found(algo_name(), provider);	73,026✔
256	}
257
258	std::unique_ptr<PK_Ops::Verification> ECDSA_PublicKey::create_x509_verification_op(	2,119✔
259	const AlgorithmIdentifier& signature_algorithm, std::string_view provider) const {
260	if(provider == "base" \|\| provider.empty()) {	2,119✔
261	return std::make_unique<ECDSA_Verification_Operation>(*this, signature_algorithm);	2,119✔
262	}
263
264	throw Provider_Not_Found(algo_name(), provider);	×
265	}
266
267	std::unique_ptr<PK_Ops::Signature> ECDSA_PrivateKey::create_signature_op(RandomNumberGenerator& rng,	706✔
268	std::string_view params,
269	std::string_view provider) const {
270	if(provider == "base" \|\| provider.empty()) {	813✔
271	return std::make_unique<ECDSA_Signature_Operation>(*this, params, rng);	394✔
272	}
273
274	throw Provider_Not_Found(algo_name(), provider);	624✔
275	}
276
277	} // namespace Botan

randombit / botan / 6642806734

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