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1 | /** |
2 | * \file rsa_internal.h | |
3 | * | |
4 | * \brief Context-independent RSA helper functions | |
5 | * | |
6 | * This module declares some RSA-related helper functions useful when | |
7 | * implementing the RSA interface. These functions are provided in a separate | |
8 | * compilation unit in order to make it easy for designers of alternative RSA | |
9 | * implementations to use them in their own code, as it is conceived that the | |
10 | * functionality they provide will be necessary for most complete | |
11 | * implementations. | |
12 | * | |
13 | * End-users of Mbed TLS who are not providing their own alternative RSA | |
14 | * implementations should not use these functions directly, and should instead | |
15 | * use only the functions declared in rsa.h. | |
16 | * | |
17 | * The interface provided by this module will be maintained through LTS (Long | |
18 | * Term Support) branches of Mbed TLS, but may otherwise be subject to change, | |
19 | * and must be considered an internal interface of the library. | |
20 | * | |
21 | * There are two classes of helper functions: | |
22 | * | |
23 | * (1) Parameter-generating helpers. These are: | |
24 | * - mbedtls_rsa_deduce_primes | |
25 | * - mbedtls_rsa_deduce_private_exponent | |
26 | * - mbedtls_rsa_deduce_crt | |
27 | * Each of these functions takes a set of core RSA parameters and | |
28 | * generates some other, or CRT related parameters. | |
29 | * | |
30 | * (2) Parameter-checking helpers. These are: | |
31 | * - mbedtls_rsa_validate_params | |
32 | * - mbedtls_rsa_validate_crt | |
33 | * They take a set of core or CRT related RSA parameters and check their | |
34 | * validity. | |
35 | * | |
36 | */ | |
37 | /* | |
38 | * Copyright (C) 2006-2017, ARM Limited, All Rights Reserved | |
39 | * SPDX-License-Identifier: GPL-2.0 | |
40 | * | |
41 | * This program is free software; you can redistribute it and/or modify | |
42 | * it under the terms of the GNU General Public License as published by | |
43 | * the Free Software Foundation; either version 2 of the License, or | |
44 | * (at your option) any later version. | |
45 | * | |
46 | * This program is distributed in the hope that it will be useful, | |
47 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
48 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
49 | * GNU General Public License for more details. | |
50 | * | |
51 | * You should have received a copy of the GNU General Public License along | |
52 | * with this program; if not, write to the Free Software Foundation, Inc., | |
53 | * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. | |
54 | * | |
55 | * This file is part of mbed TLS (https://tls.mbed.org) | |
56 | * | |
57 | */ | |
58 | ||
59 | #ifndef MBEDTLS_RSA_INTERNAL_H | |
60 | #define MBEDTLS_RSA_INTERNAL_H | |
61 | ||
62 | #if !defined(MBEDTLS_CONFIG_FILE) | |
63 | #include "config.h" | |
64 | #else | |
65 | #include MBEDTLS_CONFIG_FILE | |
66 | #endif | |
67 | ||
68 | #include "bignum.h" | |
69 | ||
70 | #ifdef __cplusplus | |
71 | extern "C" { | |
72 | #endif | |
73 | ||
74 | ||
75 | /** | |
76 | * \brief Compute RSA prime moduli P, Q from public modulus N=PQ | |
77 | * and a pair of private and public key. | |
78 | * | |
79 | * \note This is a 'static' helper function not operating on | |
80 | * an RSA context. Alternative implementations need not | |
81 | * overwrite it. | |
82 | * | |
83 | * \param N RSA modulus N = PQ, with P, Q to be found | |
84 | * \param E RSA public exponent | |
85 | * \param D RSA private exponent | |
86 | * \param P Pointer to MPI holding first prime factor of N on success | |
87 | * \param Q Pointer to MPI holding second prime factor of N on success | |
88 | * | |
89 | * \return | |
90 | * - 0 if successful. In this case, P and Q constitute a | |
91 | * factorization of N. | |
92 | * - A non-zero error code otherwise. | |
93 | * | |
94 | * \note It is neither checked that P, Q are prime nor that | |
95 | * D, E are modular inverses wrt. P-1 and Q-1. For that, | |
96 | * use the helper function \c mbedtls_rsa_validate_params. | |
97 | * | |
98 | */ | |
99 | int mbedtls_rsa_deduce_primes( mbedtls_mpi const *N, mbedtls_mpi const *E, | |
100 | mbedtls_mpi const *D, | |
101 | mbedtls_mpi *P, mbedtls_mpi *Q ); | |
102 | ||
103 | /** | |
104 | * \brief Compute RSA private exponent from | |
105 | * prime moduli and public key. | |
106 | * | |
107 | * \note This is a 'static' helper function not operating on | |
108 | * an RSA context. Alternative implementations need not | |
109 | * overwrite it. | |
110 | * | |
111 | * \param P First prime factor of RSA modulus | |
112 | * \param Q Second prime factor of RSA modulus | |
113 | * \param E RSA public exponent | |
114 | * \param D Pointer to MPI holding the private exponent on success. | |
115 | * | |
116 | * \return | |
117 | * - 0 if successful. In this case, D is set to a simultaneous | |
118 | * modular inverse of E modulo both P-1 and Q-1. | |
119 | * - A non-zero error code otherwise. | |
120 | * | |
121 | * \note This function does not check whether P and Q are primes. | |
122 | * | |
123 | */ | |
124 | int mbedtls_rsa_deduce_private_exponent( mbedtls_mpi const *P, | |
125 | mbedtls_mpi const *Q, | |
126 | mbedtls_mpi const *E, | |
127 | mbedtls_mpi *D ); | |
128 | ||
129 | ||
130 | /** | |
131 | * \brief Generate RSA-CRT parameters | |
132 | * | |
133 | * \note This is a 'static' helper function not operating on | |
134 | * an RSA context. Alternative implementations need not | |
135 | * overwrite it. | |
136 | * | |
137 | * \param P First prime factor of N | |
138 | * \param Q Second prime factor of N | |
139 | * \param D RSA private exponent | |
140 | * \param DP Output variable for D modulo P-1 | |
141 | * \param DQ Output variable for D modulo Q-1 | |
142 | * \param QP Output variable for the modular inverse of Q modulo P. | |
143 | * | |
144 | * \return 0 on success, non-zero error code otherwise. | |
145 | * | |
146 | * \note This function does not check whether P, Q are | |
147 | * prime and whether D is a valid private exponent. | |
148 | * | |
149 | */ | |
150 | int mbedtls_rsa_deduce_crt( const mbedtls_mpi *P, const mbedtls_mpi *Q, | |
151 | const mbedtls_mpi *D, mbedtls_mpi *DP, | |
152 | mbedtls_mpi *DQ, mbedtls_mpi *QP ); | |
153 | ||
154 | ||
155 | /** | |
156 | * \brief Check validity of core RSA parameters | |
157 | * | |
158 | * \note This is a 'static' helper function not operating on | |
159 | * an RSA context. Alternative implementations need not | |
160 | * overwrite it. | |
161 | * | |
162 | * \param N RSA modulus N = PQ | |
163 | * \param P First prime factor of N | |
164 | * \param Q Second prime factor of N | |
165 | * \param D RSA private exponent | |
166 | * \param E RSA public exponent | |
167 | * \param f_rng PRNG to be used for primality check, or NULL | |
168 | * \param p_rng PRNG context for f_rng, or NULL | |
169 | * | |
170 | * \return | |
171 | * - 0 if the following conditions are satisfied | |
172 | * if all relevant parameters are provided: | |
173 | * - P prime if f_rng != NULL (%) | |
174 | * - Q prime if f_rng != NULL (%) | |
175 | * - 1 < N = P * Q | |
176 | * - 1 < D, E < N | |
177 | * - D and E are modular inverses modulo P-1 and Q-1 | |
178 | * (%) This is only done if MBEDTLS_GENPRIME is defined. | |
179 | * - A non-zero error code otherwise. | |
180 | * | |
181 | * \note The function can be used with a restricted set of arguments | |
182 | * to perform specific checks only. E.g., calling it with | |
183 | * (-,P,-,-,-) and a PRNG amounts to a primality check for P. | |
184 | */ | |
185 | int mbedtls_rsa_validate_params( const mbedtls_mpi *N, const mbedtls_mpi *P, | |
186 | const mbedtls_mpi *Q, const mbedtls_mpi *D, | |
187 | const mbedtls_mpi *E, | |
188 | int (*f_rng)(void *, unsigned char *, size_t), | |
189 | void *p_rng ); | |
190 | ||
191 | /** | |
192 | * \brief Check validity of RSA CRT parameters | |
193 | * | |
194 | * \note This is a 'static' helper function not operating on | |
195 | * an RSA context. Alternative implementations need not | |
196 | * overwrite it. | |
197 | * | |
198 | * \param P First prime factor of RSA modulus | |
199 | * \param Q Second prime factor of RSA modulus | |
200 | * \param D RSA private exponent | |
201 | * \param DP MPI to check for D modulo P-1 | |
202 | * \param DQ MPI to check for D modulo P-1 | |
203 | * \param QP MPI to check for the modular inverse of Q modulo P. | |
204 | * | |
205 | * \return | |
206 | * - 0 if the following conditions are satisfied: | |
207 | * - D = DP mod P-1 if P, D, DP != NULL | |
208 | * - Q = DQ mod P-1 if P, D, DQ != NULL | |
209 | * - QP = Q^-1 mod P if P, Q, QP != NULL | |
210 | * - \c MBEDTLS_ERR_RSA_KEY_CHECK_FAILED if check failed, | |
211 | * potentially including \c MBEDTLS_ERR_MPI_XXX if some | |
212 | * MPI calculations failed. | |
213 | * - \c MBEDTLS_ERR_RSA_BAD_INPUT_DATA if insufficient | |
214 | * data was provided to check DP, DQ or QP. | |
215 | * | |
216 | * \note The function can be used with a restricted set of arguments | |
217 | * to perform specific checks only. E.g., calling it with the | |
218 | * parameters (P, -, D, DP, -, -) will check DP = D mod P-1. | |
219 | */ | |
220 | int mbedtls_rsa_validate_crt( const mbedtls_mpi *P, const mbedtls_mpi *Q, | |
221 | const mbedtls_mpi *D, const mbedtls_mpi *DP, | |
222 | const mbedtls_mpi *DQ, const mbedtls_mpi *QP ); | |
223 | ||
224 | #ifdef __cplusplus | |
225 | } | |
226 | #endif | |
227 | ||
228 | #endif /* rsa_internal.h */ |