bignum

Big number operations. More...

Typedefs
typedef struct BigNum	BigNum
	Internal representation of large numbers.

Functions
EpidStatus	NewBigNum (size_t data_size_bytes, BigNum **bignum)
	Constructs a new BigNum. More...
void	DeleteBigNum (BigNum **bignum)
	Deletes a previously allocated BigNum. More...
EpidStatus	ReadBigNum (ConstOctStr bn_str, size_t strlen, BigNum *bn)
	Deserializes a BigNum from a string. More...
EpidStatus	WriteBigNum (BigNum const *bn, size_t strlen, OctStr bn_str)
	Serializes a BigNum to a string. More...
EpidStatus	BigNumAdd (BigNum const *a, BigNum const *b, BigNum *r)
	Adds two BigNum values. More...
EpidStatus	BigNumSub (BigNum const *a, BigNum const *b, BigNum *r)
	Subtracts two BigNum values. More...
EpidStatus	BigNumMul (BigNum const *a, BigNum const *b, BigNum *r)
	Multiplies two BigNum values. More...
EpidStatus	BigNumDiv (BigNum const *a, BigNum const *b, BigNum *q, BigNum *r)
	Divides two BigNum values. More...
EpidStatus	BigNumMod (BigNum const *a, BigNum const *b, BigNum *r)
	Computes modular reduction for BigNum value by specified modulus. More...
EpidStatus	BigNumIsEven (BigNum const *a, bool *is_even)
	Checks if a BigNum is even. More...
EpidStatus	BigNumIsZero (BigNum const *a, bool *is_zero)
	Checks if a BigNum is zero. More...
EpidStatus	BigNumPow2N (unsigned int n, BigNum *r)
	Raises 2 to the given power. More...

Detailed Description

Big number operations.

This module provides an API for working with large numbers. BigNums represent non-negative integers.

Each BigNum variable represents a number of a byte-size set when the variable was created. BigNum variables cannot be re-sized after they are created.

Function Documentation

BigNumAdd()

EpidStatus BigNumAdd	(	BigNum const *	a,
		BigNum const *	b,
		BigNum *	r
	)

Adds two BigNum values.

Parameters

[in]	a	The first operand to be added.
[in]	b	The second operand to be added.
[out]	r	The result of adding a and b.

Returns

EpidStatus

BigNumDiv()

EpidStatus BigNumDiv	(	BigNum const *	a,
		BigNum const *	b,
		BigNum *	q,
		BigNum *	r
	)

Divides two BigNum values.

Note

Only needed for Intel(R) EPID 1.1 verification.

Parameters

[in]	a	Dividend parameter.
[in]	b	Divisor parameter.
[out]	q	Quotient of result.
[out]	r	Remainder of result.

Returns

EpidStatus

BigNumIsEven()

EpidStatus BigNumIsEven	(	BigNum const *	a,
		bool *	is_even
	)

Checks if a BigNum is even.

Parameters

[in]	a	The BigNum to check.
[out]	is_even	The result of the check.

Returns

EpidStatus

BigNumIsZero()

EpidStatus BigNumIsZero	(	BigNum const *	a,
		bool *	is_zero
	)

Checks if a BigNum is zero.

Parameters

[in]	a	The BigNum to check.
[out]	is_zero	The result of the check.

Returns

EpidStatus

BigNumMod()

EpidStatus BigNumMod	(	BigNum const *	a,
		BigNum const *	b,
		BigNum *	r
	)

Computes modular reduction for BigNum value by specified modulus.

Parameters

[in]	a	The BigNum value.
[in]	b	The modulus.
[out]	r	Modular reduction result.

Returns

EpidStatus

BigNumMul()

EpidStatus BigNumMul	(	BigNum const *	a,
		BigNum const *	b,
		BigNum *	r
	)

Multiplies two BigNum values.

Parameters

[in]	a	The first operand to be multiplied.
[in]	b	The second operand to be multiplied.
[out]	r	The result of multiplying a and b.

Returns

EpidStatus

BigNumPow2N()

EpidStatus BigNumPow2N	(	unsigned int	n,
		BigNum *	r
	)

Raises 2 to the given power.

Parameters

[in]	n	The power.
[out]	r	The result of 2^n.

Returns

EpidStatus

BigNumSub()

EpidStatus BigNumSub	(	BigNum const *	a,
		BigNum const *	b,
		BigNum *	r
	)

Subtracts two BigNum values.

Parameters

[in]	a	The first operand to use in subtraction.
[in]	b	The second operand to use in subtraction.
[out]	r	The result of subtracting a and b.

Returns

EpidStatus

DeleteBigNum()

void DeleteBigNum

(

BigNum **

bignum

)

Deletes a previously allocated BigNum.

Frees memory pointed to by bignum. Nulls the pointer.

Parameters

[in]

bignum

The BigNum. Can be NULL.

See also

NewBigNum

NewBigNum()

EpidStatus NewBigNum	(	size_t	data_size_bytes,
		BigNum **	bignum
	)

Constructs a new BigNum.

Allocates memory and creates a new BigNum.

Use DeleteBigNum() to free memory.

Parameters

[in]	data_size_bytes	The size in bytes of the new number.
[out]	bignum	The BigNum.

Returns

EpidStatus

See also

DeleteBigNum

ReadBigNum()

EpidStatus ReadBigNum	(	ConstOctStr	bn_str,
		size_t	strlen,
		BigNum *	bn
	)

Deserializes a BigNum from a string.

Parameters

[in]	bn_str	The serialized value.
[in]	strlen	The size of bn_str in bytes.
[out]	bn	The target BigNum.

Returns

EpidStatus

WriteBigNum()

EpidStatus WriteBigNum	(	BigNum const *	bn,
		size_t	strlen,
		OctStr	bn_str
	)

Serializes a BigNum to a string.

Parameters

[in]	bn	The BigNum to be serialized.
[in]	strlen	The size of bn_str in bytes.
[out]	bn_str	The target string.

Returns

EpidStatus