Developer Guide and Reference for Intel® Integrated Performance Primitives Cryptography
GFpECGetPointOctString
Retrieves coordinates of a point on an elliptic curve defined over GF(p).
Syntax
IppStatus ippsGFpECGetPointOctString(const IppsGFpECPointState* pPoint, Ipps8u* pStr, int lenStr, IppsGFpECState* pEC);
Include Files
ippcp.h
Parameters
| pPoint | Pointer to the context of the elliptic curve point. | 
| pStr | Pointer to the target string of octets. | 
| lenStr | Available length of pStr, in bytes. | 
| pEC | Pointer to the context of the elliptic curve cryptosystem. | 
Description
This function retrieves the coordinates of pPoint on the pEC elliptic curve from the point context, converts each X and Y coordinate into the octet string and stores them in pStrso so that the left half contains X and the right half contains Y point’s coordinate. Before using this function, define the elliptic curve domain parameters using one of the following functions: ECCPSet, or ECCPSetStd and GFpECSetSubgroup.
Return Values
| ippStsNoErr | Indicates no error. Any other value indicates an error or warning. | 
| ippStsNullPtrErr | Indicates an error when pPoint or pEC is NULL. | 
| ippStsContextMatchErr | Indicates an error when one of the contexts pointed bypPoint orpEC is not valid or not a definedsubgroup. | 
| ippStsNotSupportedModeErr | Indicates an error when the finite field over which the elliptic curve is initialized is not prime. | 
| ippStsOutOfRangeErr | Indicates an error when the size of a point coordinate is not equal to the size of the GF(p) element. | 
| ippStsSizeErr | Indicates an error when strLen != 2*gfelementLen, where gfelementLen is the size of the GF(p) element. |