mbed TLS v2.2.0
Data Structures | Macros | Typedefs | Functions
bignum.h File Reference

Detailed Description

Multi-precision integer library.

Copyright (C) 2006-2015, ARM Limited, All Rights Reserved SPDX-License-Identifier: Apache-2.0

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

This file is part of mbed TLS (https://tls.mbed.org)

Definition in file bignum.h.

#include <config-sl-crypto-all-acceleration.h>
#include <stddef.h>
#include <stdint.h>
Include dependency graph for bignum.h:
This graph shows which files directly or indirectly include this file:

Go to the source code of this file.

Data Structures

struct  mbedtls_mpi
 MPI structure. More...
 

Macros

#define MBEDTLS_ERR_MPI_FILE_IO_ERROR   -0x0002
 An error occurred while reading from or writing to a file. More...
 
#define MBEDTLS_ERR_MPI_BAD_INPUT_DATA   -0x0004
 Bad input parameters to function. More...
 
#define MBEDTLS_ERR_MPI_INVALID_CHARACTER   -0x0006
 There is an invalid character in the digit string. More...
 
#define MBEDTLS_ERR_MPI_BUFFER_TOO_SMALL   -0x0008
 The buffer is too small to write to. More...
 
#define MBEDTLS_ERR_MPI_NEGATIVE_VALUE   -0x000A
 The input arguments are negative or result in illegal output. More...
 
#define MBEDTLS_ERR_MPI_DIVISION_BY_ZERO   -0x000C
 The input argument for division is zero, which is not allowed. More...
 
#define MBEDTLS_ERR_MPI_NOT_ACCEPTABLE   -0x000E
 The input arguments are not acceptable. More...
 
#define MBEDTLS_ERR_MPI_ALLOC_FAILED   -0x0010
 Memory allocation failed. More...
 
#define MBEDTLS_MPI_CHK(f)   do { if( ( ret = f ) != 0 ) goto cleanup; } while( 0 )
 
#define MBEDTLS_MPI_MAX_LIMBS   10000
 
#define MBEDTLS_MPI_WINDOW_SIZE   6
 Maximum windows size used. More...
 
#define MBEDTLS_MPI_MAX_BITS   ( 8 * MBEDTLS_MPI_MAX_SIZE )
 Maximum number of bits for usable MPIs. More...
 
#define MBEDTLS_MPI_MAX_BITS_SCALE100   ( 100 * MBEDTLS_MPI_MAX_BITS )
 
#define MBEDTLS_LN_2_DIV_LN_10_SCALE100   332
 
#define MBEDTLS_MPI_RW_BUFFER_SIZE   ( ((MBEDTLS_MPI_MAX_BITS_SCALE100 + MBEDTLS_LN_2_DIV_LN_10_SCALE100 - 1) / MBEDTLS_LN_2_DIV_LN_10_SCALE100) + 10 + 6 )
 
#define MBEDTLS_HAVE_INT32
 
#define MBEDTLS_HAVE_UDBL
 

Typedefs

typedef int32_t mbedtls_mpi_sint
 
typedef uint32_t mbedtls_mpi_uint
 
typedef uint64_t mbedtls_t_udbl
 

Functions

void mbedtls_mpi_init (mbedtls_mpi *X)
 Initialize one MPI (make internal references valid) This just makes it ready to be set or freed, but does not define a value for the MPI. More...
 
void mbedtls_mpi_free (mbedtls_mpi *X)
 Unallocate one MPI. More...
 
int mbedtls_mpi_grow (mbedtls_mpi *X, size_t nblimbs)
 Enlarge to the specified number of limbs. More...
 
int mbedtls_mpi_shrink (mbedtls_mpi *X, size_t nblimbs)
 Resize down, keeping at least the specified number of limbs. More...
 
int mbedtls_mpi_copy (mbedtls_mpi *X, const mbedtls_mpi *Y)
 Copy the contents of Y into X. More...
 
void mbedtls_mpi_swap (mbedtls_mpi *X, mbedtls_mpi *Y)
 Swap the contents of X and Y. More...
 
int mbedtls_mpi_safe_cond_assign (mbedtls_mpi *X, const mbedtls_mpi *Y, unsigned char assign)
 Safe conditional assignement X = Y if assign is 1. More...
 
int mbedtls_mpi_safe_cond_swap (mbedtls_mpi *X, mbedtls_mpi *Y, unsigned char assign)
 Safe conditional swap X <-> Y if swap is 1. More...
 
int mbedtls_mpi_lset (mbedtls_mpi *X, mbedtls_mpi_sint z)
 Set value from integer. More...
 
int mbedtls_mpi_get_bit (const mbedtls_mpi *X, size_t pos)
 Get a specific bit from X. More...
 
int mbedtls_mpi_set_bit (mbedtls_mpi *X, size_t pos, unsigned char val)
 Set a bit of X to a specific value of 0 or 1. More...
 
size_t mbedtls_mpi_lsb (const mbedtls_mpi *X)
 Return the number of zero-bits before the least significant '1' bit. More...
 
size_t mbedtls_mpi_bitlen (const mbedtls_mpi *X)
 Return the number of bits up to and including the most significant '1' bit'. More...
 
size_t mbedtls_mpi_size (const mbedtls_mpi *X)
 Return the total size in bytes. More...
 
int mbedtls_mpi_read_string (mbedtls_mpi *X, int radix, const char *s)
 Import from an ASCII string. More...
 
int mbedtls_mpi_write_string (const mbedtls_mpi *X, int radix, char *buf, size_t buflen, size_t *olen)
 Export into an ASCII string. More...
 
int mbedtls_mpi_read_binary (mbedtls_mpi *X, const unsigned char *buf, size_t buflen)
 Import X from unsigned binary data, big endian. More...
 
int mbedtls_mpi_write_binary (const mbedtls_mpi *X, unsigned char *buf, size_t buflen)
 Export X into unsigned binary data, big endian. More...
 
int mbedtls_mpi_shift_l (mbedtls_mpi *X, size_t count)
 Left-shift: X <<= count. More...
 
int mbedtls_mpi_shift_r (mbedtls_mpi *X, size_t count)
 Right-shift: X >>= count. More...
 
int mbedtls_mpi_cmp_abs (const mbedtls_mpi *X, const mbedtls_mpi *Y)
 Compare unsigned values. More...
 
int mbedtls_mpi_cmp_mpi (const mbedtls_mpi *X, const mbedtls_mpi *Y)
 Compare signed values. More...
 
int mbedtls_mpi_cmp_int (const mbedtls_mpi *X, mbedtls_mpi_sint z)
 Compare signed values. More...
 
int mbedtls_mpi_add_abs (mbedtls_mpi *X, const mbedtls_mpi *A, const mbedtls_mpi *B)
 Unsigned addition: X = |A| + |B|. More...
 
int mbedtls_mpi_sub_abs (mbedtls_mpi *X, const mbedtls_mpi *A, const mbedtls_mpi *B)
 Unsigned subtraction: X = |A| - |B|. More...
 
int mbedtls_mpi_add_mpi (mbedtls_mpi *X, const mbedtls_mpi *A, const mbedtls_mpi *B)
 Signed addition: X = A + B. More...
 
int mbedtls_mpi_sub_mpi (mbedtls_mpi *X, const mbedtls_mpi *A, const mbedtls_mpi *B)
 Signed subtraction: X = A - B. More...
 
int mbedtls_mpi_add_int (mbedtls_mpi *X, const mbedtls_mpi *A, mbedtls_mpi_sint b)
 Signed addition: X = A + b. More...
 
int mbedtls_mpi_sub_int (mbedtls_mpi *X, const mbedtls_mpi *A, mbedtls_mpi_sint b)
 Signed subtraction: X = A - b. More...
 
int mbedtls_mpi_mul_mpi (mbedtls_mpi *X, const mbedtls_mpi *A, const mbedtls_mpi *B)
 Baseline multiplication: X = A * B. More...
 
int mbedtls_mpi_mul_int (mbedtls_mpi *X, const mbedtls_mpi *A, mbedtls_mpi_uint b)
 Baseline multiplication: X = A * b. More...
 
int mbedtls_mpi_div_mpi (mbedtls_mpi *Q, mbedtls_mpi *R, const mbedtls_mpi *A, const mbedtls_mpi *B)
 Division by mbedtls_mpi: A = Q * B + R. More...
 
int mbedtls_mpi_div_int (mbedtls_mpi *Q, mbedtls_mpi *R, const mbedtls_mpi *A, mbedtls_mpi_sint b)
 Division by int: A = Q * b + R. More...
 
int mbedtls_mpi_mod_mpi (mbedtls_mpi *R, const mbedtls_mpi *A, const mbedtls_mpi *B)
 Modulo: R = A mod B. More...
 
int mbedtls_mpi_mod_int (mbedtls_mpi_uint *r, const mbedtls_mpi *A, mbedtls_mpi_sint b)
 Modulo: r = A mod b. More...
 
int mbedtls_mpi_exp_mod (mbedtls_mpi *X, const mbedtls_mpi *A, const mbedtls_mpi *E, const mbedtls_mpi *N, mbedtls_mpi *_RR)
 Sliding-window exponentiation: X = A^E mod N. More...
 
int mbedtls_mpi_fill_random (mbedtls_mpi *X, size_t size, int(*f_rng)(void *, unsigned char *, size_t), void *p_rng)
 Fill an MPI X with size bytes of random. More...
 
int mbedtls_mpi_gcd (mbedtls_mpi *G, const mbedtls_mpi *A, const mbedtls_mpi *B)
 Greatest common divisor: G = gcd(A, B) More...
 
int mbedtls_mpi_inv_mod (mbedtls_mpi *X, const mbedtls_mpi *A, const mbedtls_mpi *N)
 Modular inverse: X = A^-1 mod N. More...
 
int mbedtls_mpi_is_prime (const mbedtls_mpi *X, int(*f_rng)(void *, unsigned char *, size_t), void *p_rng)
 Miller-Rabin primality test. More...
 
int mbedtls_mpi_gen_prime (mbedtls_mpi *X, size_t nbits, int dh_flag, int(*f_rng)(void *, unsigned char *, size_t), void *p_rng)
 Prime number generation. More...
 
int mbedtls_mpi_self_test (int verbose)
 Checkup routine. More...
 

Macro Definition Documentation

#define MBEDTLS_ERR_MPI_ALLOC_FAILED   -0x0010

Memory allocation failed.

Definition at line 46 of file bignum.h.

#define MBEDTLS_ERR_MPI_BAD_INPUT_DATA   -0x0004

Bad input parameters to function.

Definition at line 40 of file bignum.h.

#define MBEDTLS_ERR_MPI_BUFFER_TOO_SMALL   -0x0008

The buffer is too small to write to.

Definition at line 42 of file bignum.h.

#define MBEDTLS_ERR_MPI_DIVISION_BY_ZERO   -0x000C

The input argument for division is zero, which is not allowed.

Definition at line 44 of file bignum.h.

#define MBEDTLS_ERR_MPI_FILE_IO_ERROR   -0x0002

An error occurred while reading from or writing to a file.

Definition at line 39 of file bignum.h.

#define MBEDTLS_ERR_MPI_INVALID_CHARACTER   -0x0006

There is an invalid character in the digit string.

Definition at line 41 of file bignum.h.

#define MBEDTLS_ERR_MPI_NEGATIVE_VALUE   -0x000A

The input arguments are negative or result in illegal output.

Definition at line 43 of file bignum.h.

#define MBEDTLS_ERR_MPI_NOT_ACCEPTABLE   -0x000E

The input arguments are not acceptable.

Definition at line 45 of file bignum.h.

#define MBEDTLS_HAVE_INT32

Definition at line 128 of file bignum.h.

#define MBEDTLS_HAVE_UDBL

Definition at line 132 of file bignum.h.

#define MBEDTLS_LN_2_DIV_LN_10_SCALE100   332

Definition at line 100 of file bignum.h.

#define MBEDTLS_MPI_CHK (   f)    do { if( ( ret = f ) != 0 ) goto cleanup; } while( 0 )

Definition at line 48 of file bignum.h.

#define MBEDTLS_MPI_MAX_BITS   ( 8 * MBEDTLS_MPI_MAX_SIZE )

Maximum number of bits for usable MPIs.

Definition at line 79 of file bignum.h.

#define MBEDTLS_MPI_MAX_BITS_SCALE100   ( 100 * MBEDTLS_MPI_MAX_BITS )

Definition at line 99 of file bignum.h.

#define MBEDTLS_MPI_MAX_LIMBS   10000

Definition at line 53 of file bignum.h.

#define MBEDTLS_MPI_RW_BUFFER_SIZE   ( ((MBEDTLS_MPI_MAX_BITS_SCALE100 + MBEDTLS_LN_2_DIV_LN_10_SCALE100 - 1) / MBEDTLS_LN_2_DIV_LN_10_SCALE100) + 10 + 6 )

Definition at line 101 of file bignum.h.

#define MBEDTLS_MPI_WINDOW_SIZE   6

Maximum windows size used.

Definition at line 65 of file bignum.h.

Typedef Documentation

typedef int32_t mbedtls_mpi_sint

Definition at line 129 of file bignum.h.

typedef uint32_t mbedtls_mpi_uint

Definition at line 130 of file bignum.h.

typedef uint64_t mbedtls_t_udbl

Definition at line 131 of file bignum.h.

Function Documentation

int mbedtls_mpi_add_abs ( mbedtls_mpi X,
const mbedtls_mpi A,
const mbedtls_mpi B 
)

Unsigned addition: X = |A| + |B|.

Parameters
XDestination MPI
ALeft-hand MPI
BRight-hand MPI
Returns
0 if successful, MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed
int mbedtls_mpi_add_int ( mbedtls_mpi X,
const mbedtls_mpi A,
mbedtls_mpi_sint  b 
)

Signed addition: X = A + b.

Parameters
XDestination MPI
ALeft-hand MPI
bThe integer value to add
Returns
0 if successful, MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed
int mbedtls_mpi_add_mpi ( mbedtls_mpi X,
const mbedtls_mpi A,
const mbedtls_mpi B 
)

Signed addition: X = A + B.

Parameters
XDestination MPI
ALeft-hand MPI
BRight-hand MPI
Returns
0 if successful, MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed
size_t mbedtls_mpi_bitlen ( const mbedtls_mpi X)

Return the number of bits up to and including the most significant '1' bit'.

Note: Thus also the one-based index of the most significant '1' bit

Parameters
XMPI to use
int mbedtls_mpi_cmp_abs ( const mbedtls_mpi X,
const mbedtls_mpi Y 
)

Compare unsigned values.

Parameters
XLeft-hand MPI
YRight-hand MPI
Returns
1 if |X| is greater than |Y|, -1 if |X| is lesser than |Y| or 0 if |X| is equal to |Y|
int mbedtls_mpi_cmp_int ( const mbedtls_mpi X,
mbedtls_mpi_sint  z 
)

Compare signed values.

Parameters
XLeft-hand MPI
zThe integer value to compare to
Returns
1 if X is greater than z, -1 if X is lesser than z or 0 if X is equal to z
int mbedtls_mpi_cmp_mpi ( const mbedtls_mpi X,
const mbedtls_mpi Y 
)

Compare signed values.

Parameters
XLeft-hand MPI
YRight-hand MPI
Returns
1 if X is greater than Y, -1 if X is lesser than Y or 0 if X is equal to Y
int mbedtls_mpi_copy ( mbedtls_mpi X,
const mbedtls_mpi Y 
)

Copy the contents of Y into X.

Parameters
XDestination MPI
YSource MPI
Returns
0 if successful, MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed
int mbedtls_mpi_div_int ( mbedtls_mpi Q,
mbedtls_mpi R,
const mbedtls_mpi A,
mbedtls_mpi_sint  b 
)

Division by int: A = Q * b + R.

Parameters
QDestination MPI for the quotient
RDestination MPI for the rest value
ALeft-hand MPI
bInteger to divide by
Returns
0 if successful, MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed, MBEDTLS_ERR_MPI_DIVISION_BY_ZERO if b == 0
Note
Either Q or R can be NULL.
int mbedtls_mpi_div_mpi ( mbedtls_mpi Q,
mbedtls_mpi R,
const mbedtls_mpi A,
const mbedtls_mpi B 
)

Division by mbedtls_mpi: A = Q * B + R.

Parameters
QDestination MPI for the quotient
RDestination MPI for the rest value
ALeft-hand MPI
BRight-hand MPI
Returns
0 if successful, MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed, MBEDTLS_ERR_MPI_DIVISION_BY_ZERO if B == 0
Note
Either Q or R can be NULL.
int mbedtls_mpi_exp_mod ( mbedtls_mpi X,
const mbedtls_mpi A,
const mbedtls_mpi E,
const mbedtls_mpi N,
mbedtls_mpi _RR 
)

Sliding-window exponentiation: X = A^E mod N.

Parameters
XDestination MPI
ALeft-hand MPI
EExponent MPI
NModular MPI
_RRSpeed-up MPI used for recalculations
Returns
0 if successful, MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed, MBEDTLS_ERR_MPI_BAD_INPUT_DATA if N is negative or even or if E is negative
Note
_RR is used to avoid re-computing R*R mod N across multiple calls, which speeds up things a bit. It can be set to NULL if the extra performance is unneeded.
int mbedtls_mpi_fill_random ( mbedtls_mpi X,
size_t  size,
int(*)(void *, unsigned char *, size_t)  f_rng,
void *  p_rng 
)

Fill an MPI X with size bytes of random.

Parameters
XDestination MPI
sizeSize in bytes
f_rngRNG function
p_rngRNG parameter
Returns
0 if successful, MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed
void mbedtls_mpi_free ( mbedtls_mpi X)

Unallocate one MPI.

Parameters
XOne MPI to unallocate.
int mbedtls_mpi_gcd ( mbedtls_mpi G,
const mbedtls_mpi A,
const mbedtls_mpi B 
)

Greatest common divisor: G = gcd(A, B)

Parameters
GDestination MPI
ALeft-hand MPI
BRight-hand MPI
Returns
0 if successful, MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed
int mbedtls_mpi_gen_prime ( mbedtls_mpi X,
size_t  nbits,
int  dh_flag,
int(*)(void *, unsigned char *, size_t)  f_rng,
void *  p_rng 
)

Prime number generation.

Parameters
XDestination MPI
nbitsRequired size of X in bits ( 3 <= nbits <= MBEDTLS_MPI_MAX_BITS )
dh_flagIf 1, then (X-1)/2 will be prime too
f_rngRNG function
p_rngRNG parameter
Returns
0 if successful (probably prime), MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed, MBEDTLS_ERR_MPI_BAD_INPUT_DATA if nbits is < 3
int mbedtls_mpi_get_bit ( const mbedtls_mpi X,
size_t  pos 
)

Get a specific bit from X.

Parameters
XMPI to use
posZero-based index of the bit in X
Returns
Either a 0 or a 1
int mbedtls_mpi_grow ( mbedtls_mpi X,
size_t  nblimbs 
)

Enlarge to the specified number of limbs.

Parameters
XMPI to grow
nblimbsThe target number of limbs
Returns
0 if successful, MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed
void mbedtls_mpi_init ( mbedtls_mpi X)

Initialize one MPI (make internal references valid) This just makes it ready to be set or freed, but does not define a value for the MPI.

Parameters
XOne MPI to initialize.
int mbedtls_mpi_inv_mod ( mbedtls_mpi X,
const mbedtls_mpi A,
const mbedtls_mpi N 
)

Modular inverse: X = A^-1 mod N.

Parameters
XDestination MPI
ALeft-hand MPI
NRight-hand MPI
Returns
0 if successful, MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed, MBEDTLS_ERR_MPI_BAD_INPUT_DATA if N is negative or nil MBEDTLS_ERR_MPI_NOT_ACCEPTABLE if A has no inverse mod N
int mbedtls_mpi_is_prime ( const mbedtls_mpi X,
int(*)(void *, unsigned char *, size_t)  f_rng,
void *  p_rng 
)

Miller-Rabin primality test.

Parameters
XMPI to check
f_rngRNG function
p_rngRNG parameter
Returns
0 if successful (probably prime), MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed, MBEDTLS_ERR_MPI_NOT_ACCEPTABLE if X is not prime
size_t mbedtls_mpi_lsb ( const mbedtls_mpi X)

Return the number of zero-bits before the least significant '1' bit.

Note: Thus also the zero-based index of the least significant '1' bit

Parameters
XMPI to use
int mbedtls_mpi_lset ( mbedtls_mpi X,
mbedtls_mpi_sint  z 
)

Set value from integer.

Parameters
XMPI to set
zValue to use
Returns
0 if successful, MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed
int mbedtls_mpi_mod_int ( mbedtls_mpi_uint r,
const mbedtls_mpi A,
mbedtls_mpi_sint  b 
)

Modulo: r = A mod b.

Parameters
rDestination mbedtls_mpi_uint
ALeft-hand MPI
bInteger to divide by
Returns
0 if successful, MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed, MBEDTLS_ERR_MPI_DIVISION_BY_ZERO if b == 0, MBEDTLS_ERR_MPI_NEGATIVE_VALUE if b < 0
int mbedtls_mpi_mod_mpi ( mbedtls_mpi R,
const mbedtls_mpi A,
const mbedtls_mpi B 
)

Modulo: R = A mod B.

Parameters
RDestination MPI for the rest value
ALeft-hand MPI
BRight-hand MPI
Returns
0 if successful, MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed, MBEDTLS_ERR_MPI_DIVISION_BY_ZERO if B == 0, MBEDTLS_ERR_MPI_NEGATIVE_VALUE if B < 0
int mbedtls_mpi_mul_int ( mbedtls_mpi X,
const mbedtls_mpi A,
mbedtls_mpi_uint  b 
)

Baseline multiplication: X = A * b.

Parameters
XDestination MPI
ALeft-hand MPI
bThe unsigned integer value to multiply with
Note
b is unsigned
Returns
0 if successful, MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed
int mbedtls_mpi_mul_mpi ( mbedtls_mpi X,
const mbedtls_mpi A,
const mbedtls_mpi B 
)

Baseline multiplication: X = A * B.

Parameters
XDestination MPI
ALeft-hand MPI
BRight-hand MPI
Returns
0 if successful, MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed
int mbedtls_mpi_read_binary ( mbedtls_mpi X,
const unsigned char *  buf,
size_t  buflen 
)

Import X from unsigned binary data, big endian.

Parameters
XDestination MPI
bufInput buffer
buflenInput buffer size
Returns
0 if successful, MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed
int mbedtls_mpi_read_string ( mbedtls_mpi X,
int  radix,
const char *  s 
)

Import from an ASCII string.

Parameters
XDestination MPI
radixInput numeric base
sNull-terminated string buffer
Returns
0 if successful, or a MBEDTLS_ERR_MPI_XXX error code
int mbedtls_mpi_safe_cond_assign ( mbedtls_mpi X,
const mbedtls_mpi Y,
unsigned char  assign 
)

Safe conditional assignement X = Y if assign is 1.

Parameters
XMPI to conditionally assign to
YValue to be assigned
assign1: perform the assignment, 0: keep X's original value
Returns
0 if successful, MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed,
Note
This function is equivalent to if( assign ) mbedtls_mpi_copy( X, Y ); except that it avoids leaking any information about whether the assignment was done or not (the above code may leak information through branch prediction and/or memory access patterns analysis).
int mbedtls_mpi_safe_cond_swap ( mbedtls_mpi X,
mbedtls_mpi Y,
unsigned char  assign 
)

Safe conditional swap X <-> Y if swap is 1.

Parameters
XFirst mbedtls_mpi value
YSecond mbedtls_mpi value
assign1: perform the swap, 0: keep X and Y's original values
Returns
0 if successful, MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed,
Note
This function is equivalent to if( assign ) mbedtls_mpi_swap( X, Y ); except that it avoids leaking any information about whether the assignment was done or not (the above code may leak information through branch prediction and/or memory access patterns analysis).
int mbedtls_mpi_self_test ( int  verbose)

Checkup routine.

Returns
0 if successful, or 1 if the test failed
int mbedtls_mpi_set_bit ( mbedtls_mpi X,
size_t  pos,
unsigned char  val 
)

Set a bit of X to a specific value of 0 or 1.

Note
Will grow X if necessary to set a bit to 1 in a not yet existing limb. Will not grow if bit should be set to 0
Parameters
XMPI to use
posZero-based index of the bit in X
valThe value to set the bit to (0 or 1)
Returns
0 if successful, MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed, MBEDTLS_ERR_MPI_BAD_INPUT_DATA if val is not 0 or 1
int mbedtls_mpi_shift_l ( mbedtls_mpi X,
size_t  count 
)

Left-shift: X <<= count.

Parameters
XMPI to shift
countAmount to shift
Returns
0 if successful, MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed
int mbedtls_mpi_shift_r ( mbedtls_mpi X,
size_t  count 
)

Right-shift: X >>= count.

Parameters
XMPI to shift
countAmount to shift
Returns
0 if successful, MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed
int mbedtls_mpi_shrink ( mbedtls_mpi X,
size_t  nblimbs 
)

Resize down, keeping at least the specified number of limbs.

Parameters
XMPI to shrink
nblimbsThe minimum number of limbs to keep
Returns
0 if successful, MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed
size_t mbedtls_mpi_size ( const mbedtls_mpi X)

Return the total size in bytes.

Parameters
XMPI to use
int mbedtls_mpi_sub_abs ( mbedtls_mpi X,
const mbedtls_mpi A,
const mbedtls_mpi B 
)

Unsigned subtraction: X = |A| - |B|.

Parameters
XDestination MPI
ALeft-hand MPI
BRight-hand MPI
Returns
0 if successful, MBEDTLS_ERR_MPI_NEGATIVE_VALUE if B is greater than A
int mbedtls_mpi_sub_int ( mbedtls_mpi X,
const mbedtls_mpi A,
mbedtls_mpi_sint  b 
)

Signed subtraction: X = A - b.

Parameters
XDestination MPI
ALeft-hand MPI
bThe integer value to subtract
Returns
0 if successful, MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed
int mbedtls_mpi_sub_mpi ( mbedtls_mpi X,
const mbedtls_mpi A,
const mbedtls_mpi B 
)

Signed subtraction: X = A - B.

Parameters
XDestination MPI
ALeft-hand MPI
BRight-hand MPI
Returns
0 if successful, MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed
void mbedtls_mpi_swap ( mbedtls_mpi X,
mbedtls_mpi Y 
)

Swap the contents of X and Y.

Parameters
XFirst MPI value
YSecond MPI value
int mbedtls_mpi_write_binary ( const mbedtls_mpi X,
unsigned char *  buf,
size_t  buflen 
)

Export X into unsigned binary data, big endian.

Always fills the whole buffer, which will start with zeros if the number is smaller.

Parameters
XSource MPI
bufOutput buffer
buflenOutput buffer size
Returns
0 if successful, MBEDTLS_ERR_MPI_BUFFER_TOO_SMALL if buf isn't large enough
int mbedtls_mpi_write_string ( const mbedtls_mpi X,
int  radix,
char *  buf,
size_t  buflen,
size_t *  olen 
)

Export into an ASCII string.

Parameters
XSource MPI
radixOutput numeric base
bufBuffer to write the string to
buflenLength of buf
olenLength of the string written, including final NUL byte
Returns
0 if successful, or a MBEDTLS_ERR_MPI_XXX error code. *olen is always updated to reflect the amount of data that has (or would have) been written.
Note
Call this function with buflen = 0 to obtain the minimum required buffer size in *olen.