DLPGetDP
DLPGetDP
Retrieves a particular domain parameter of the DL-based cryptosystem over GF(p).
Syntax
IppStatus ippsDLPGetDP(IppsBigNumState*
pDP
, IppDLPKeyTag
tag
, const IppsDLPState*
pCtx
);
Include Files
ippcp.h
Parameters
- pDP
- Pointer to the output Big Number context.
- tag
- Tag specifying the domain parameter to be retrieved.
- pCtx
- Pointer to the cryptosystem context.
Description
The function retrieves value of a particular domain parameter of the DL-based cryptosystem from the
IppsDLPState
context and stores the value in the Big Number context *pDP
. The domain parameter to be retrieved is determined by tag
as follows:- Iftag==IppDLPkeyP, the function retrieves value of the characteristicp, the size of the prime finite field GF(p).
- Iftag==IppDLPkeyR, the function retrieves value of the characteristicr, the prime divisor of (p-1) and the order ofg.
- Iftag==IppDLPkeyG, the function retrieves value of the characteristicg,the element of GF(p) generating a multiplicative subgroup of orderr.
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 isNULL.
- ippStsContextMatchErr
- Indicates an error condition if the context parameter does not match the operation.
- ippStsIncompleteContextErr
- Indicates an error condition if the cryptosystem context has not been properly set up.
- ippStsOutOfRangeErr
- Indicates an error condition if the Big Number specified bypDPis too small for the DL parameter.
- ippStsBadArgErr
- Indicates an error condition if the domain parameter specified by the tag does not match theIppsDLPStatecontext.