fq.h File Reference

Definition of Fq math. More...

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

Functions
int	FqInField (FqElem const *in)
	Test if an element is in Fq. More...
void	FqAdd (FqElem *result, FqElem const *left, FqElem const *right)
	Add two elements of Fq. More...
void	FqSub (FqElem *result, FqElem const *left, FqElem const *right)
	Subtract two elements of Fq. More...
void	FqMul (FqElem *result, FqElem const *left, FqElem const *right)
	Multiply two elements of Fq. More...
void	FqExp (FqElem *result, FqElem const *base, VeryLargeInt const *exp)
	Exponentiate an element of Fq by a large integer. More...
void	FqCp (FqElem *result, FqElem const *in)
	Copy an element's value. More...
int	FqIsZero (FqElem const *value)
	Test if an element is zero. More...
void	FqInv (FqElem *result, FqElem const *in)
	Invert an element of Fq. More...
void	FqNeg (FqElem *result, FqElem const *in)
	Negate an element of Fq. More...
void	FqSquare (FqElem *result, FqElem const *in)
	Square an element of Fq. More...
void	FqClear (FqElem *result)
	Clear an element's value. More...
void	FqSet (FqElem *result, uint32_t in)
	Set an element's value. More...
int	FqEq (FqElem const *left, FqElem const *right)
	Test if two elements in Fq are equal. More...
void	FqCondSet (FqElem *result, FqElem const *true_val, FqElem const *false_val, int truth_val)
	Conditionally Set an element's value to one of two values. More...
int	FqSqrt (FqElem *result, FqElem const *in)
	Compute the Square root of an element of Fq. More...
int	FqRand (FqElem *result, BitSupplier rnd_func, void *rnd_param)
	Generate a random element of Fq. More...
void	FqFromHash (FqElem *result, unsigned char const *hash, size_t len)
	Reinterpret a buffer as an element of Fq. More...

Detailed Description

Definition of Fq math.

Function Documentation

FqAdd()

void FqAdd	(	FqElem *	result,
		FqElem const *	left,
		FqElem const *	right
	)

Add two elements of Fq.

Parameters

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

FqClear()

void FqClear

(

FqElem *

result

)

Clear an element's value.

Parameters

[out]

result

element to clear.

FqCondSet()

void FqCondSet	(	FqElem *	result,
		FqElem const *	true_val,
		FqElem const *	false_val,
		int	truth_val
	)

Conditionally Set an element's value to one of two values.

Parameters

[out]	result	target.
[in]	true_val	value to set if condition is true.
[in]	false_val	value to set if condition is false.
[in]	truth_val	value of condition.

FqCp()

void FqCp	(	FqElem *	result,
		FqElem const *	in
	)

Copy an element's value.

Parameters

[out]	result	copy target.
[in]	in	copy source.

FqEq()

int FqEq	(	FqElem const *	left,
		FqElem const *	right
	)

Test if two elements in Fq 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.

FqExp()

void FqExp	(	FqElem *	result,
		FqElem const *	base,
		VeryLargeInt const *	exp
	)

Exponentiate an element of Fq by a large integer.

Parameters

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

FqFromHash()

void FqFromHash	(	FqElem *	result,
		unsigned char const *	hash,
		size_t	len
	)

Reinterpret a buffer as an element of Fq.

Parameters

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

FqInField()

int FqInField

(

FqElem const *

in

)

Test if an element is in Fq.

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.

FqInv()

void FqInv	(	FqElem *	result,
		FqElem const *	in
	)

Invert an element of Fq.

Parameters

[out]	result	the inverse of the element.
[in]	in	the element to invert.

FqIsZero()

int FqIsZero

(

FqElem const *

value

)

Test if an element is zero.

Parameters

[in]

value

the element to test.

Returns

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

FqMul()

void FqMul	(	FqElem *	result,
		FqElem const *	left,
		FqElem const *	right
	)

Multiply two elements of Fq.

Parameters

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

FqNeg()

void FqNeg	(	FqElem *	result,
		FqElem const *	in
	)

Negate an element of Fq.

This function was formerly called as FqConst.

Parameters

[out]	result	the negative of the element.
[in]	in	the element to negate.

FqRand()

int FqRand	(	FqElem *	result,
		BitSupplier	rnd_func,
		void *	rnd_param
	)

Generate a random element of Fq.

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.

FqSet()

void FqSet	(	FqElem *	result,
		uint32_t	in
	)

Set an element's value.

Parameters

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

FqSqrt()

int FqSqrt	(	FqElem *	result,
		FqElem const *	in
	)

Compute the Square root of an element of Fq.

Parameters

[out]	result	the square root of the element.
[in]	in	the element to find the square root of.

Returns

A value different from zero (i.e., true) if the square root exists. Zero (i.e., false) otherwise.

FqSquare()

void FqSquare	(	FqElem *	result,
		FqElem const *	in
	)

Square an element of Fq.

Parameters

[out]	result	the square of the element.
[in]	in	the element to square.

FqSub()

void FqSub	(	FqElem *	result,
		FqElem const *	left,
		FqElem const *	right
	)

Subtract two elements of Fq.

Parameters

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