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1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /* mpi.h - Multi Precision Integers
3 * Copyright (C) 1994, 1996, 1998, 1999,
4 * 2000, 2001 Free Software Foundation, Inc.
6 * This file is part of GNUPG.
8 * Note: This code is heavily based on the GNU MP Library.
9 * Actually it's the same code with only minor changes in the
10 * way the data is stored; this is to support the abstraction
11 * of an optional secure memory allocation which may be used
12 * to avoid revealing of sensitive data due to paging etc.
13 * The GNU MP Library itself is published under the LGPL;
14 * however I decided to publish this code under the plain GPL.
20 #include <linux/types.h>
21 #include <linux/scatterlist.h>
23 #define BYTES_PER_MPI_LIMB (BITS_PER_LONG / 8)
24 #define BITS_PER_MPI_LIMB BITS_PER_LONG
26 typedef unsigned long int mpi_limb_t
;
27 typedef signed long int mpi_limb_signed_t
;
30 int alloced
; /* array size (# of allocated limbs) */
31 int nlimbs
; /* number of valid limbs */
32 int nbits
; /* the real number of valid bits (info only) */
33 int sign
; /* indicates a negative number */
34 unsigned flags
; /* bit 0: array must be allocated in secure memory space */
36 /* bit 2: the limb is a pointer to some m_alloced data */
37 mpi_limb_t
*d
; /* array with the limbs */
40 typedef struct gcry_mpi
*MPI
;
42 #define mpi_get_nlimbs(a) ((a)->nlimbs)
43 #define mpi_has_sign(a) ((a)->sign)
46 MPI
mpi_alloc(unsigned nlimbs
);
47 void mpi_clear(MPI a
);
49 int mpi_resize(MPI a
, unsigned nlimbs
);
51 static inline MPI
mpi_new(unsigned int nbits
)
53 return mpi_alloc((nbits
+ BITS_PER_MPI_LIMB
- 1) / BITS_PER_MPI_LIMB
);
57 MPI
mpi_alloc_like(MPI a
);
58 void mpi_snatch(MPI w
, MPI u
);
59 MPI
mpi_set(MPI w
, MPI u
);
60 MPI
mpi_set_ui(MPI w
, unsigned long u
);
61 MPI
mpi_alloc_set_ui(unsigned long u
);
62 void mpi_swap_cond(MPI a
, MPI b
, unsigned long swap
);
64 /* Constants used to return constant MPIs. See mpi_init if you
65 * want to add more constants.
67 #define MPI_NUMBER_OF_CONSTANTS 6
68 enum gcry_mpi_constants
{
77 MPI
mpi_const(enum gcry_mpi_constants no
);
81 /* Different formats of external big integer representation. */
82 enum gcry_mpi_format
{
84 GCRYMPI_FMT_STD
= 1, /* Twos complement stored without length. */
85 GCRYMPI_FMT_PGP
= 2, /* As used by OpenPGP (unsigned only). */
86 GCRYMPI_FMT_SSH
= 3, /* As used by SSH (like STD but with length). */
87 GCRYMPI_FMT_HEX
= 4, /* Hex format. */
88 GCRYMPI_FMT_USG
= 5, /* Like STD but unsigned. */
89 GCRYMPI_FMT_OPAQUE
= 8 /* Opaque format (some functions only). */
92 MPI
mpi_read_raw_data(const void *xbuffer
, size_t nbytes
);
93 MPI
mpi_read_from_buffer(const void *buffer
, unsigned *ret_nread
);
94 int mpi_fromstr(MPI val
, const char *str
);
95 MPI
mpi_scanval(const char *string
);
96 MPI
mpi_read_raw_from_sgl(struct scatterlist
*sgl
, unsigned int len
);
97 void *mpi_get_buffer(MPI a
, unsigned *nbytes
, int *sign
);
98 int mpi_read_buffer(MPI a
, uint8_t *buf
, unsigned buf_len
, unsigned *nbytes
,
100 int mpi_write_to_sgl(MPI a
, struct scatterlist
*sg
, unsigned nbytes
,
102 int mpi_print(enum gcry_mpi_format format
, unsigned char *buffer
,
103 size_t buflen
, size_t *nwritten
, MPI a
);
106 void mpi_mod(MPI rem
, MPI dividend
, MPI divisor
);
108 /* Context used with Barrett reduction. */
109 struct barrett_ctx_s
;
110 typedef struct barrett_ctx_s
*mpi_barrett_t
;
112 mpi_barrett_t
mpi_barrett_init(MPI m
, int copy
);
113 void mpi_barrett_free(mpi_barrett_t ctx
);
114 void mpi_mod_barrett(MPI r
, MPI x
, mpi_barrett_t ctx
);
115 void mpi_mul_barrett(MPI w
, MPI u
, MPI v
, mpi_barrett_t ctx
);
118 int mpi_powm(MPI res
, MPI base
, MPI exp
, MPI mod
);
121 int mpi_cmp_ui(MPI u
, ulong v
);
122 int mpi_cmp(MPI u
, MPI v
);
123 int mpi_cmpabs(MPI u
, MPI v
);
125 /*-- mpi-sub-ui.c --*/
126 int mpi_sub_ui(MPI w
, MPI u
, unsigned long vval
);
129 void mpi_normalize(MPI a
);
130 unsigned mpi_get_nbits(MPI a
);
131 int mpi_test_bit(MPI a
, unsigned int n
);
132 void mpi_set_bit(MPI a
, unsigned int n
);
133 void mpi_set_highbit(MPI a
, unsigned int n
);
134 void mpi_clear_highbit(MPI a
, unsigned int n
);
135 void mpi_clear_bit(MPI a
, unsigned int n
);
136 void mpi_rshift_limbs(MPI a
, unsigned int count
);
137 void mpi_rshift(MPI x
, MPI a
, unsigned int n
);
138 void mpi_lshift_limbs(MPI a
, unsigned int count
);
139 void mpi_lshift(MPI x
, MPI a
, unsigned int n
);
142 void mpi_add_ui(MPI w
, MPI u
, unsigned long v
);
143 void mpi_add(MPI w
, MPI u
, MPI v
);
144 void mpi_sub(MPI w
, MPI u
, MPI v
);
145 void mpi_addm(MPI w
, MPI u
, MPI v
, MPI m
);
146 void mpi_subm(MPI w
, MPI u
, MPI v
, MPI m
);
149 void mpi_mul(MPI w
, MPI u
, MPI v
);
150 void mpi_mulm(MPI w
, MPI u
, MPI v
, MPI m
);
153 void mpi_tdiv_r(MPI rem
, MPI num
, MPI den
);
154 void mpi_fdiv_r(MPI rem
, MPI dividend
, MPI divisor
);
155 void mpi_fdiv_q(MPI quot
, MPI dividend
, MPI divisor
);
158 int mpi_invm(MPI x
, MPI a
, MPI n
);
162 /* Object to represent a point in projective coordinates */
163 struct gcry_mpi_point
{
169 typedef struct gcry_mpi_point
*MPI_POINT
;
171 /* Models describing an elliptic curve */
172 enum gcry_mpi_ec_models
{
173 /* The Short Weierstrass equation is
176 MPI_EC_WEIERSTRASS
= 0,
177 /* The Montgomery equation is
178 * by^2 = x^3 + ax^2 + x
181 /* The Twisted Edwards equation is
182 * ax^2 + y^2 = 1 + bx^2y^2
183 * Note that we use 'b' instead of the commonly used 'd'.
188 /* Dialects used with elliptic curves */
190 ECC_DIALECT_STANDARD
= 0,
192 ECC_DIALECT_SAFECURVE
195 /* This context is used with all our EC functions. */
197 enum gcry_mpi_ec_models model
; /* The model describing this curve. */
198 enum ecc_dialects dialect
; /* The ECC dialect used with the curve. */
199 int flags
; /* Public key flags (not always used). */
200 unsigned int nbits
; /* Number of bits. */
202 /* Domain parameters. Note that they may not all be set and if set
203 * the MPIs may be flagged as constant.
205 MPI p
; /* Prime specifying the field GF(p). */
206 MPI a
; /* First coefficient of the Weierstrass equation. */
207 MPI b
; /* Second coefficient of the Weierstrass equation. */
208 MPI_POINT G
; /* Base point (generator). */
209 MPI n
; /* Order of G. */
210 unsigned int h
; /* Cofactor. */
212 /* The actual key. May not be set. */
213 MPI_POINT Q
; /* Public key. */
214 MPI d
; /* Private key. */
216 const char *name
; /* Name of the curve. */
218 /* This structure is private to mpi/ec.c! */
221 unsigned int a_is_pminus3
:1;
222 unsigned int two_inv_p
:1;
223 } valid
; /* Flags to help setting the helper vars below. */
225 int a_is_pminus3
; /* True if A = P - 3. */
229 mpi_barrett_t p_barrett
;
231 /* Scratch variables. */
234 /* Helper for fast reduction. */
235 /* int nist_nbits; /\* If this is a NIST curve, the # of bits. *\/ */
240 /* Curve specific computation routines for the field. */
241 void (*addm
)(MPI w
, MPI u
, MPI v
, struct mpi_ec_ctx
*ctx
);
242 void (*subm
)(MPI w
, MPI u
, MPI v
, struct mpi_ec_ctx
*ec
);
243 void (*mulm
)(MPI w
, MPI u
, MPI v
, struct mpi_ec_ctx
*ctx
);
244 void (*pow2
)(MPI w
, const MPI b
, struct mpi_ec_ctx
*ctx
);
245 void (*mul2
)(MPI w
, MPI u
, struct mpi_ec_ctx
*ctx
);
248 void mpi_ec_init(struct mpi_ec_ctx
*ctx
, enum gcry_mpi_ec_models model
,
249 enum ecc_dialects dialect
,
250 int flags
, MPI p
, MPI a
, MPI b
);
251 void mpi_ec_deinit(struct mpi_ec_ctx
*ctx
);
252 MPI_POINT
mpi_point_new(unsigned int nbits
);
253 void mpi_point_release(MPI_POINT p
);
254 void mpi_point_init(MPI_POINT p
);
255 void mpi_point_free_parts(MPI_POINT p
);
256 int mpi_ec_get_affine(MPI x
, MPI y
, MPI_POINT point
, struct mpi_ec_ctx
*ctx
);
257 void mpi_ec_add_points(MPI_POINT result
,
258 MPI_POINT p1
, MPI_POINT p2
,
259 struct mpi_ec_ctx
*ctx
);
260 void mpi_ec_mul_point(MPI_POINT result
,
261 MPI scalar
, MPI_POINT point
,
262 struct mpi_ec_ctx
*ctx
);
263 int mpi_ec_curve_point(MPI_POINT point
, struct mpi_ec_ctx
*ctx
);
265 /* inline functions */
268 * mpi_get_size() - returns max size required to store the number
270 * @a: A multi precision integer for which we want to allocate a buffer
272 * Return: size required to store the number
274 static inline unsigned int mpi_get_size(MPI a
)
276 return a
->nlimbs
* BYTES_PER_MPI_LIMB
;
278 #endif /*G10_MPI_H */