fp.h File Reference

Definition of Fp math. More...

#include <stddef.h>
#include <stdint.h>
#include "epid/common/bitsupplier.h"

Functions
int	FpInField (FpElem const *in)
	Test if an element is in Fp. More...
void	FpAdd (FpElem *result, FpElem const *left, FpElem const *right)
	Add two elements of Fp. More...
void	FpMul (FpElem *result, FpElem const *left, FpElem const *right)
	Multiply two elements of Fp. More...
void	FpSub (FpElem *result, FpElem const *left, FpElem const *right)
	Subtract two elements of Fp. More...
void	FpExp (FpElem *result, FpElem const *base, VeryLargeInt const *exp)
	Exponentiate an element of Fp by a large integer. More...
void	FpNeg (FpElem *result, FpElem const *in)
	Negate an element of Fp. More...
int	FpEq (FpElem const *left, FpElem const *right)
	Test if two elements in Fp are equal. More...
void	FpInv (FpElem *result, FpElem const *in)
	Invert an element of Fp. More...
int	FpRand (FpElem *result, BitSupplier rnd_func, void *rnd_param)
	Generate a random element of Fp. More...
int	FpRandNonzero (FpElem *result, BitSupplier rnd_func, void *rnd_param)
	Generate a non-zero random element of Fp. More...
void	FpClear (FpElem *result)
	Clear an element of Fp. More...
void	FpSet (FpElem *result, uint32_t in)
	Set a element of Fp's value. More...
void	FpFromHash (FpElem *result, unsigned char const *hash, size_t len)
	Reinterpret a buffer as an element of Fp. More...

Detailed Description

Definition of Fp math.

Function Documentation

FpAdd()

void FpAdd	(	FpElem *	result,
		FpElem const *	left,
		FpElem const *	right
	)

Add two elements of Fp.

Parameters

[out]	result	of adding left and right.
[in]	left	The first operand to be added.
[in]	right	The second operand to be added.

FpClear()

void FpClear

(

FpElem *

result

)

Clear an element of Fp.

Parameters

[out]

result

value to clear.

FpEq()

int FpEq	(	FpElem const *	left,
		FpElem const *	right
	)

Test if two elements in Fp are equal.

Parameters

[in]	left	The first operand to be tested.
[in]	right	The second operand to be tested.

Returns

A value different from zero (i.e., true) if indeed the values are equal. Zero (i.e., false) otherwise.

FpExp()

void FpExp	(	FpElem *	result,
		FpElem const *	base,
		VeryLargeInt const *	exp
	)

Exponentiate an element of Fp by a large integer.

Parameters

[out]	result	target.
[in]	base	the base.
[in]	exp	the exponent.

FpFromHash()

void FpFromHash	(	FpElem *	result,
		unsigned char const *	hash,
		size_t	len
	)

Reinterpret a buffer as an element of Fp.

Parameters

[out]	result	target.
[in]	hash	buffer to reinterpret.
[in]	len	length of hash in bytes.

FpInField()

int FpInField

(

FpElem const *

in

)

Test if an element is in Fp.

Parameters

[in]

in

the element to test

Returns

A value different from zero (i.e., true) indeed the value is in the field. Zero (i.e., false) otherwise.

FpInv()

void FpInv	(	FpElem *	result,
		FpElem const *	in
	)

Invert an element of Fp.

Parameters

[out]	result	target.
[in]	in	the value to invert.

FpMul()

void FpMul	(	FpElem *	result,
		FpElem const *	left,
		FpElem const *	right
	)

Multiply two elements of Fp.

Parameters

[out]	result	of multiplying left and right.
[in]	left	The first operand to be multiplied.
[in]	right	The second operand to be multiplied.

FpNeg()

void FpNeg	(	FpElem *	result,
		FpElem const *	in
	)

Negate an element of Fp.

Parameters

[out]	result	target.
[in]	in	the value to negate.

FpRand()

int FpRand	(	FpElem *	result,
		BitSupplier	rnd_func,
		void *	rnd_param
	)

Generate a random element of Fp.

Parameters

[in]	result	the random value.
[in]	rnd_func	Random number generator.
[in]	rnd_param	Pass through context data for rnd_func.

Returns

A value different from zero (i.e., true) if on success. Zero (i.e., false) otherwise.

FpRandNonzero()

int FpRandNonzero	(	FpElem *	result,
		BitSupplier	rnd_func,
		void *	rnd_param
	)

Generate a non-zero random element of Fp.

Parameters

[in]	result	the random value.
[in]	rnd_func	Random number generator.
[in]	rnd_param	Pass through context data for rnd_func.

Returns

A value different from zero (i.e., true) if on success. Zero (i.e., false) otherwise.

FpSet()

void FpSet	(	FpElem *	result,
		uint32_t	in
	)

Set a element of Fp's value.

Parameters

[out]	result	target.
[in]	in	value to set.

FpSub()

void FpSub	(	FpElem *	result,
		FpElem const *	left,
		FpElem const *	right
	)

Subtract two elements of Fp.

Parameters

[out]	result	of subtracting left from right.
[in]	left	The operand to be subtracted from.
[in]	right	The operand to subtract.