RSAGenerate

Generates key components for the desired RSA cryptographic system.

Syntax

IppStatus ippsRSAGenerate(IppsBigNumState* pE, int nBitsN, int nBitsP, int nTrials, IppsRSAState* pCtx, IppBitSupplier rndFunc, void* pRndParam);

pE	Pointer to the IppsBigNumState context of the newly generated RSA public exponent key.
nBitsN	Length of the RSA system in bits (that is, the length of the composite RSA modulus `n` in bits).
nBitsP	Length in bits of one of the two prime factors of the RSA modulus.
nTrials	Security parameter specified for the Miller-Rabin probable primality.
pCtx	Pointer to the IppsRSAState context.
rndFunc	Pseudorandom number generator.
pRndParam	Pointer to the context of the pseudorandom number generator.

The function is declared in the ippcp.h file. This function generates the desired RSA cryptographic system based on the following data:

Input *pE context, specifying the initial value for searching the RSA public exponent.
Input parameters nBitsN and nBitsP, specifying the bit lengths of the composite RSA modulus n and the largest RSA prime factor p, respectively.

This function sequentially performs the following computations:

Generates random probable prime numbers p and q using the specified pseudorandom number generator rndFunc.
Computes the RSA composite modulus n = (p*q) and the RSA private exponent d.
Computes all other CRT-related RSA components.

To generate RSA keys using the RSAGenerate function, call it in the following sequence of steps:

Establish the pseudorandom number generator.
Define the size of the RSA cryptosystem, that is, lengths nBitsN and nBitsP of n and p (in bits), respectively.
Define the RSA cryptosystem using the IppRSAprivate flag. To do this, use the following function calls:

ippsRSAGetSize(nBitsN, nBitsP, IppRSAprivate, &rsaCtxSize);

ippsRSAInit(nBitsN, nBitsP, IppRSAprivate, pCtx);

where pCtx is the memory allocated for the RSA context.
Define the initial value of the public key E and make the call

ippsRSAGenerate(pE, nBitsN, nBitsP, nTrials, pCtx, rndFunc, pRndParam);

If ippsRSAGenerate returns IppNoErr, keys are generated.

If ippsRSAGenerate returns ippStsInsufficientEntropy, repeat this step from the beginning.

Note
ippsRSAGenerate may change the initial value of the public key E.

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 the context parameter does not match the operation.
ippStsNotSupportedModeErr	Indicates an error condition if RSA context was initialized with the IppRSApublic flag.
ippStsBadArgErr	Indicates an error condition in cases not explicitly mentioned above.
ippStsInsufficientEntropy	Indicates a warning condition if prime generation fails due to poor choice of entropy.