ECCBSet

Sets up elliptic curve domain parameters over GF(2 ^m).

Syntax

IppStatus ippsECCBSet(const IppsBigNumState* pPrime, const IppsBigNumState* pA, const IppsBigNumState* pB, const IppsBigNumState* pGX, const IppsBigNumState* pGY, const IppsBigNumState* pOrder, int cofactor, IppsECCBState* pECC);

Parameters

pPrime	Pointer to the irreducible binary polynomial f(x) of degree m which specifies the presentation of the field GF(2^m).
pA	Pointer to the coefficient A of the equation defining the elliptic curve.
pB	Pointer to the coefficient B of the equation defining the elliptic curve.
pGX	Pointer to the x-coordinate of the elliptic curve base point.
pGY	Pointer to the y-coordinate of the elliptic curve base point.
pOrder	Pointer to the order of the elliptic curve base point.
cofactor	Cofactor.
pECC	Pointer to the context of the cryptosystem.

Description

This function is declared in the ippcp.h file.

The function sets up the elliptic curve domain parameters over a binary finite field GF(2^m). These are as follows:

pPrime sets up the characteristic f(x) of degree m, which specifies the presentation of the field GF(2^m).
pA, pB set up the coefficients A and B of the equation defining the elliptic curve:

y² + x · y = x³ + A · x² + B in GF(2^m)
pGX, pGY are pointers to the affine coordinates of the elliptic curve base point G.
pOrder is a pointer to the order n of the elliptic curve base point G such that
n · G = O, where O is the point at infinity and n is a prime number.
cofactor sets up the ratio h of a general number of points #E on the elliptic curve (including the point at infinity) to the order n of the base point:

h = #E/n .

The domain parameters are set in the cryptosystem context which must be already created by the ECCBGetSize and ECCBInit functions.

Return Values

ippStsNoErr	Indicates no error. Any other value indicates an error or warning.
ippStsNullPtrErr	Indicates an error condition if any of the specified pointers is NULL.
ippStsContextMatchErr	Indicates an error condition if one of the contexts pointed by pPrime, pA, pB, pGX, pGY, pOrder, and pECC is not valid.
ippStsRangeErr	Indicates an error condition if the memory size of one of the parameters pointed by pPrime, pA, pB, pGX, pGY, pOrder, and pECC is more than the value of feBitSize in the ECCBInit function or the value of cofactor is less than or equal to zero.