Multi-precision integer library. More...

Data Structures
struct	mbedtls_mpi
	MPI structure. More...
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.
void	mbedtls_mpi_free (mbedtls_mpi *X)
	Unallocate one MPI.
int	mbedtls_mpi_grow (mbedtls_mpi *X, size_t nblimbs)
	Enlarge to the specified number of limbs.
int	mbedtls_mpi_shrink (mbedtls_mpi *X, size_t nblimbs)
	Resize down, keeping at least the specified number of limbs.
int	mbedtls_mpi_copy (mbedtls_mpi X, const mbedtls_mpi Y)
	Copy the contents of Y into X.
void	mbedtls_mpi_swap (mbedtls_mpi X, mbedtls_mpi Y)
	Swap the contents of X and Y.
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.
int	mbedtls_mpi_safe_cond_swap (mbedtls_mpi X, mbedtls_mpi Y, unsigned char assign)
	Safe conditional swap X <-> Y if swap is 1.
int	mbedtls_mpi_lset (mbedtls_mpi *X, mbedtls_mpi_sint z)
	Set value from integer.
int	mbedtls_mpi_get_bit (const mbedtls_mpi *X, size_t pos)
	Get a specific bit from X.
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.
size_t	mbedtls_mpi_lsb (const mbedtls_mpi *X)
	Return the number of zero-bits before the least significant '1' bit.
size_t	mbedtls_mpi_bitlen (const mbedtls_mpi *X)
	Return the number of bits up to and including the most significant '1' bit'.
size_t	mbedtls_mpi_size (const mbedtls_mpi *X)
	Return the total size in bytes.
int	mbedtls_mpi_read_string (mbedtls_mpi X, int radix, const char s)
	Import from an ASCII string.
int	mbedtls_mpi_write_string (const mbedtls_mpi X, int radix, char buf, size_t buflen, size_t *olen)
	Export into an ASCII string.
int	mbedtls_mpi_read_file (mbedtls_mpi X, int radix, FILE fin)
	Read MPI from a line in an opened file.
int	mbedtls_mpi_write_file (const char p, const mbedtls_mpi X, int radix, FILE *fout)
	Write X into an opened file, or stdout if fout is NULL.
int	mbedtls_mpi_read_binary (mbedtls_mpi X, const unsigned char buf, size_t buflen)
	Import X from unsigned binary data, big endian.
int	mbedtls_mpi_write_binary (const mbedtls_mpi X, unsigned char buf, size_t buflen)
	Export X into unsigned binary data, big endian.
int	mbedtls_mpi_shift_l (mbedtls_mpi *X, size_t count)
	Left-shift: X <<= count.
int	mbedtls_mpi_shift_r (mbedtls_mpi *X, size_t count)
	Right-shift: X >>= count.
int	mbedtls_mpi_cmp_abs (const mbedtls_mpi X, const mbedtls_mpi Y)
	Compare unsigned values.
int	mbedtls_mpi_cmp_mpi (const mbedtls_mpi X, const mbedtls_mpi Y)
	Compare signed values.
int	mbedtls_mpi_cmp_int (const mbedtls_mpi *X, mbedtls_mpi_sint z)
	Compare signed values.
int	mbedtls_mpi_add_abs (mbedtls_mpi X, const mbedtls_mpi A, const mbedtls_mpi *B)
	Unsigned addition: X = \|A\| + \|B\|.
int	mbedtls_mpi_sub_abs (mbedtls_mpi X, const mbedtls_mpi A, const mbedtls_mpi *B)
	Unsigned subtraction: X = \|A\| - \|B\|.
int	mbedtls_mpi_add_mpi (mbedtls_mpi X, const mbedtls_mpi A, const mbedtls_mpi *B)
	Signed addition: X = A + B.
int	mbedtls_mpi_sub_mpi (mbedtls_mpi X, const mbedtls_mpi A, const mbedtls_mpi *B)
	Signed subtraction: X = A - B.
int	mbedtls_mpi_add_int (mbedtls_mpi X, const mbedtls_mpi A, mbedtls_mpi_sint b)
	Signed addition: X = A + b.
int	mbedtls_mpi_sub_int (mbedtls_mpi X, const mbedtls_mpi A, mbedtls_mpi_sint b)
	Signed subtraction: X = A - b.
int	mbedtls_mpi_mul_mpi (mbedtls_mpi X, const mbedtls_mpi A, const mbedtls_mpi *B)
	Baseline multiplication: X = A * B.
int	mbedtls_mpi_mul_int (mbedtls_mpi X, const mbedtls_mpi A, mbedtls_mpi_uint b)
	Baseline multiplication: X = A * b.
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.
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.
int	mbedtls_mpi_mod_mpi (mbedtls_mpi R, const mbedtls_mpi A, const mbedtls_mpi *B)
	Modulo: R = A mod B.
int	mbedtls_mpi_mod_int (mbedtls_mpi_uint r, const mbedtls_mpi A, mbedtls_mpi_sint b)
	Modulo: r = A mod b.
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.
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.
int	mbedtls_mpi_gcd (mbedtls_mpi G, const mbedtls_mpi A, const mbedtls_mpi *B)
	Greatest common divisor: G = gcd(A, B)
int	mbedtls_mpi_inv_mod (mbedtls_mpi X, const mbedtls_mpi A, const mbedtls_mpi *N)
	Modular inverse: X = A^-1 mod N.
int	mbedtls_mpi_is_prime (const mbedtls_mpi X, int(f_rng)(void , unsigned char , size_t), void *p_rng)
	Miller-Rabin primality test.
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.
int	mbedtls_mpi_self_test (int verbose)
	Checkup routine.

Detailed Description

Multi-precision integer library.

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.

Function Documentation

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

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

Parameters:

X	Destination MPI
A	Left-hand MPI
B	Right-hand MPI

Returns:: 0 if successful, MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed

Definition at line 887 of file bignum.c.

int mbedtls_mpi_add_int	(	mbedtls_mpi *	X,
		const mbedtls_mpi *	A,
		mbedtls_mpi_sint	b
	)

Signed addition: X = A + b.

Parameters:

X	Destination MPI
A	Left-hand MPI
b	The integer value to add

Returns:: 0 if successful, MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed

Definition at line 1069 of file bignum.c.

int mbedtls_mpi_add_mpi	(	mbedtls_mpi *	X,
		const mbedtls_mpi *	A,
		const mbedtls_mpi *	B
	)

Signed addition: X = A + B.

Parameters:

X	Destination MPI
A	Left-hand MPI
B	Right-hand MPI

Returns:: 0 if successful, MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed

Definition at line 1007 of file bignum.c.

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:

X	MPI to use

Definition at line 380 of file bignum.c.

int mbedtls_mpi_cmp_abs	(	const mbedtls_mpi *	X,
		const mbedtls_mpi *	Y
	)

Compare unsigned values.

Parameters:

X	Left-hand MPI
Y	Right-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|

Definition at line 808 of file bignum.c.

int mbedtls_mpi_cmp_int	(	const mbedtls_mpi *	X,
		mbedtls_mpi_sint	z
	)

Compare signed values.

Parameters:

X	Left-hand MPI
z	The 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

Definition at line 871 of file bignum.c.

int mbedtls_mpi_cmp_mpi	(	const mbedtls_mpi *	X,
		const mbedtls_mpi *	Y
	)

Compare signed values.

Parameters:

X	Left-hand MPI
Y	Right-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

Definition at line 838 of file bignum.c.

int mbedtls_mpi_copy	(	mbedtls_mpi *	X,
		const mbedtls_mpi *	Y
	)

Copy the contents of Y into X.

Parameters:

X	Destination MPI
Y	Source MPI

Returns:: 0 if successful, MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed

Definition at line 180 of file bignum.c.

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:

Q	Destination MPI for the quotient
R	Destination MPI for the rest value
A	Left-hand MPI
b	Integer 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.

Definition at line 1437 of file bignum.c.

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:

Q	Destination MPI for the quotient
R	Destination MPI for the rest value
A	Left-hand MPI
B	Right-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.

Definition at line 1322 of file bignum.c.

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:

X	Destination MPI
A	Left-hand MPI
E	Exponent MPI
N	Modular MPI
_RR	Speed-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.

Definition at line 1607 of file bignum.c.

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:

X	Destination MPI
size	Size in bytes
f_rng	RNG function
p_rng	RNG parameter

Returns:: 0 if successful, MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed

Definition at line 1871 of file bignum.c.

void mbedtls_mpi_free ( mbedtls_mpi * X )

Unallocate one MPI.

Parameters:

X	One MPI to unallocate.

Definition at line 95 of file bignum.c.

int mbedtls_mpi_gcd	(	mbedtls_mpi *	G,
		const mbedtls_mpi *	A,
		const mbedtls_mpi *	B
	)

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

Parameters:

G	Destination MPI
A	Left-hand MPI
B	Right-hand MPI

Returns:: 0 if successful, MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed

Definition at line 1815 of file bignum.c.

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:

X	Destination MPI
nbits	Required size of X in bits ( 3 <= nbits <= MBEDTLS_MPI_MAX_BITS )
dh_flag	If 1, then (X-1)/2 will be prime too
f_rng	RNG function
p_rng	RNG 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

Definition at line 2182 of file bignum.c.

int mbedtls_mpi_get_bit	(	const mbedtls_mpi *	X,
		size_t	pos
	)

Get a specific bit from X.

Parameters:

X	MPI to use
pos	Zero-based index of the bit in X

Returns:: Either a 0 or a 1

Definition at line 308 of file bignum.c.

int mbedtls_mpi_grow	(	mbedtls_mpi *	X,
		size_t	nblimbs
	)

Enlarge to the specified number of limbs.

Parameters:

X	MPI to grow
nblimbs	The target number of limbs

Returns:: 0 if successful, MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed

Definition at line 114 of file bignum.c.

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:

X	One MPI to initialize.

Definition at line 82 of file bignum.c.

int mbedtls_mpi_inv_mod	(	mbedtls_mpi *	X,
		const mbedtls_mpi *	A,
		const mbedtls_mpi *	N
	)

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

Parameters:

X	Destination MPI
A	Left-hand MPI
N	Right-hand MPI

Returns:: 0 if successful, MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed, MBEDTLS_ERR_MPI_BAD_INPUT_DATA if N is <= 1, MBEDTLS_ERR_MPI_NOT_ACCEPTABLE if A has no inverse mod N.

Definition at line 1891 of file bignum.c.

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:

X	MPI to check
f_rng	RNG function
p_rng	RNG 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

Definition at line 2150 of file bignum.c.

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:

X	MPI to use

Definition at line 347 of file bignum.c.

int mbedtls_mpi_lset	(	mbedtls_mpi *	X,
		mbedtls_mpi_sint	z
	)

Set value from integer.

Parameters:

X	MPI to set
z	Value to use

Returns:: 0 if successful, MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed

Definition at line 290 of file bignum.c.

int mbedtls_mpi_mod_int	(	mbedtls_mpi_uint *	r,
		const mbedtls_mpi *	A,
		mbedtls_mpi_sint	b
	)

Modulo: r = A mod b.

Parameters:

r	Destination mbedtls_mpi_uint
A	Left-hand MPI
b	Integer 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

Definition at line 1476 of file bignum.c.

int mbedtls_mpi_mod_mpi	(	mbedtls_mpi *	R,
		const mbedtls_mpi *	A,
		const mbedtls_mpi *	B
	)

Modulo: R = A mod B.

Parameters:

R	Destination MPI for the rest value
A	Left-hand MPI
B	Right-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

Definition at line 1453 of file bignum.c.

int mbedtls_mpi_mul_int	(	mbedtls_mpi *	X,
		const mbedtls_mpi *	A,
		mbedtls_mpi_uint	b
	)

Baseline multiplication: X = A * b.

Parameters:

X	Destination MPI
A	Left-hand MPI
b	The unsigned integer value to multiply with

Note:: b is unsigned

Returns:: 0 if successful, MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed

Definition at line 1210 of file bignum.c.

int mbedtls_mpi_mul_mpi	(	mbedtls_mpi *	X,
		const mbedtls_mpi *	A,
		const mbedtls_mpi *	B
	)

Baseline multiplication: X = A * B.

Parameters:

X	Destination MPI
A	Left-hand MPI
B	Right-hand MPI

Returns:: 0 if successful, MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed

Definition at line 1173 of file bignum.c.

int mbedtls_mpi_read_binary	(	mbedtls_mpi *	X,
		const unsigned char *	buf,
		size_t	buflen
	)

Import X from unsigned binary data, big endian.

Parameters:

X	Destination MPI
buf	Input buffer
buflen	Input buffer size

Returns:: 0 if successful, MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed

Definition at line 672 of file bignum.c.

int mbedtls_mpi_read_file	(	mbedtls_mpi *	X,
		int	radix,
		FILE *	fin
	)

Read MPI from a line in an opened file.

Parameters:

X	Destination MPI
radix	Input numeric base
fin	Input file handle

Returns:: 0 if successful, MBEDTLS_ERR_MPI_BUFFER_TOO_SMALL if the file read buffer is too small or a MBEDTLS_ERR_MPI_XXX error code

Note:: On success, this function advances the file stream to the end of the current line or to EOF.

The function returns 0 on an empty line.

Leading whitespaces are ignored, as is a '0x' prefix for radix 16.

Definition at line 600 of file bignum.c.

int mbedtls_mpi_read_string	(	mbedtls_mpi *	X,
		int	radix,
		const char *	s
	)

Import from an ASCII string.

Parameters:

X	Destination MPI
radix	Input numeric base
s	Null-terminated string buffer

Returns:: 0 if successful, or a MBEDTLS_ERR_MPI_XXX error code

Definition at line 424 of file bignum.c.

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:

X	MPI to conditionally assign to
Y	Value to be assigned
assign	1: 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).

Definition at line 228 of file bignum.c.

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:

X	First mbedtls_mpi value
Y	Second mbedtls_mpi value
assign	1: 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).

Definition at line 256 of file bignum.c.

int mbedtls_mpi_self_test ( int verbose )

Checkup routine.

Returns:: 0 if successful, or 1 if the test failed

Definition at line 2287 of file bignum.c.

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:

X	MPI to use
pos	Zero-based index of the bit in X
val	The 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

Definition at line 319 of file bignum.c.

int mbedtls_mpi_shift_l	(	mbedtls_mpi *	X,
		size_t	count
	)

Left-shift: X <<= count.

Parameters:

X	MPI to shift
count	Amount to shift

Returns:: 0 if successful, MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed

Definition at line 715 of file bignum.c.

int mbedtls_mpi_shift_r	(	mbedtls_mpi *	X,
		size_t	count
	)

Right-shift: X >>= count.

Parameters:

X	MPI to shift
count	Amount to shift

Returns:: 0 if successful, MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed

Definition at line 765 of file bignum.c.

int mbedtls_mpi_shrink	(	mbedtls_mpi *	X,
		size_t	nblimbs
	)

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

Parameters:

X	MPI to shrink
nblimbs	The minimum number of limbs to keep

Returns:: 0 if successful, MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed

Definition at line 144 of file bignum.c.

size_t mbedtls_mpi_size ( const mbedtls_mpi * X )

Return the total size in bytes.

Parameters:

X	MPI to use

Definition at line 399 of file bignum.c.

int mbedtls_mpi_sub_abs	(	mbedtls_mpi *	X,
		const mbedtls_mpi *	A,
		const mbedtls_mpi *	B
	)

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

Parameters:

X	Destination MPI
A	Left-hand MPI
B	Right-hand MPI

Returns:: 0 if successful, MBEDTLS_ERR_MPI_NEGATIVE_VALUE if B is greater than A

Definition at line 964 of file bignum.c.

int mbedtls_mpi_sub_int	(	mbedtls_mpi *	X,
		const mbedtls_mpi *	A,
		mbedtls_mpi_sint	b
	)

Signed subtraction: X = A - b.

Parameters:

X	Destination MPI
A	Left-hand MPI
b	The integer value to subtract

Returns:: 0 if successful, MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed

Definition at line 1085 of file bignum.c.

int mbedtls_mpi_sub_mpi	(	mbedtls_mpi *	X,
		const mbedtls_mpi *	A,
		const mbedtls_mpi *	B
	)

Signed subtraction: X = A - B.

Parameters:

X	Destination MPI
A	Left-hand MPI
B	Right-hand MPI

Returns:: 0 if successful, MBEDTLS_ERR_MPI_ALLOC_FAILED if memory allocation failed

Definition at line 1038 of file bignum.c.

void mbedtls_mpi_swap	(	mbedtls_mpi *	X,
		mbedtls_mpi *	Y
	)

Swap the contents of X and Y.

Parameters:

X	First MPI value
Y	Second MPI value

Definition at line 214 of file bignum.c.

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:

X	Source MPI
buf	Output buffer
buflen	Output buffer size

Returns:: 0 if successful, MBEDTLS_ERR_MPI_BUFFER_TOO_SMALL if buf isn't large enough

Definition at line 695 of file bignum.c.

int mbedtls_mpi_write_file	(	const char *	p,
		const mbedtls_mpi *	X,
		int	radix,
		FILE *	fout
	)

Write X into an opened file, or stdout if fout is NULL.

Parameters:

p	Prefix, can be NULL
X	Source MPI
radix	Output numeric base
fout	Output file handle (can be NULL)

Returns:: 0 if successful, or a MBEDTLS_ERR_MPI_XXX error code

Note:: Set fout == NULL to print X on the console.

Definition at line 633 of file bignum.c.

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:

X	Source MPI
radix	Output numeric base
buf	Buffer to write the string to
buflen	Length of buf
olen	Length 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.

Definition at line 523 of file bignum.c.

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