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/*
//
//  Purpose:
//     Cryptography Primitive.
//     DL over Prime Field
//
*/

#include "owndefs.h"
#include "owncp.h"
#include "pcpdlp.h"
#include "pcptool.h"

/*
// Size of scratch buffer, involved in MontExp operation
//
// nExponents     - number of exponents
// expBitSize     - (max) sizeof exponent (in bits)
// modulusBitSize - size of modulus (bits)
*/
static cpSize cpMontExpScratchBufferSize(cpSize modulusBitSize, cpSize expBitSize, cpSize nExponents)
{
    /* sizeof table element */
    cpSize elmDataSize = BITS_BNU_CHUNK(modulusBitSize) * sizeof(BNU_CHUNK_T);
    /* get window_size */
    cpSize w = (nExponents == 1) ? cpMontExp_WinSize(expBitSize) : /* use optimal window size, if single-scalar operation */
        nExponents;                     /* or pseudo-oprimal if multi-scalar operation */

                                        /* number of table entries */
    cpSize nPrecomputed = 1 << w;

    cpSize bufferSize = elmDataSize*nPrecomputed + (CACHE_LINE_SIZE - 1);
    return bufferSize;
}