.. _gfpecprivatekey-gfpecpublickey-gfpectstkeypair:




GFpECPrivateKey, GFpECPublicKey, GFpECTstKeyPair
================================================


Generates a private key of the elliptic curve cryptosystem over GF(p).


Syntax
------


IppStatus ippsGFpECPrivateKey(IppsBigNumState\* pPrivate,
IppsGFpECState\* pEC, IppBitSupplier rndFunc, void\* pRndParam);


IppStatus ippsGFpECPublicKey(const IppsBigNumState\* pPrivate,
IppsGFpECPoint\* pPublic, IppsGFpECState\* pEC, Ipp8u\* pScratchBuffer);


IppStatus ippsGFpECTstKeyPair(const IppsBigNumState\* pPrivate, const
IppsGFpECPoint\* pPublic, IppECResult\* pResult, IppsGFpECState\* pEC,
Ipp8u\* pScratchBuffer);


Include Files
-------------


``ippcp.h``


Parameters
----------


.. list-table:: 
   :header-rows: 0

   * - pPrivate   
     - Pointer to the private key ``privKey``.
   * - pPublic   
     - Pointer to the public key ``pubKey``.
   * - pEC   
     - Pointer to the context of the elliptic curve.
   * - rndFunc   
     - Specified Random Generator.
   * - pRndParam   
     - Pointer to the Random Generator context.
   * - pResult   
     - Pointer to the validation result.
   * - pScratchBuffer   
     - Pointer to the scratch buffer. Can be NULL.




Description
-----------


The function generates a private key ``privKey`` of the elliptic
cryptosystem over a finite field GF(``p``). The generation process
employs the user-specified rndFunc Random Generator.


The private key ``privKey`` is a number that lies in the range of [1,
``n``-1] where ``n`` is the order of the elliptic curve base point.


The memory size of the parameter ``privKey`` pointed to by pPrivate must
be not less than order of the base point, which can also be defined by
the function
`GFpECGetSubgroup <gfpecgetsubgroup.html>`__.


The elliptic curve domain parameters must be hitherto defined by the
functions:
`GFpECInitStd <gfpecinitstd.html>`__,
`GFpECInit <gfpecinit.html>`__,
`GFpECSet <gfpecset.html>`__, or
`GFpECSetSubgroup <gfpecsetsubgroup.html>`__.


Return Values
-------------


.. list-table:: 
   :header-rows: 0

   * - 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 any of the specified contexts does not match the operation.
   * - ippStsSizeErr   
     - Indicates an error condition if the parameter pointed to by pPrivate has a memory size that is less than the order ``n`` of the elliptic curve base point ``G``.
   * - ippStsIvalidPrivateKey   
     - Indicates an error condition if the value of the private key is less than that of the order of the elliptic curve base point.