Subversion Repositories planix.SVN

#include "os.h"
#include <mp.h>
#include <libsec.h>

mpint*
egencrypt(EGpub *pub, mpint *in, mpint *out)
{
        mpint *m, *k, *gamma, *delta, *pm1;
        mpint *p = pub->p, *alpha = pub->alpha;
        int plen = mpsignif(p);
        int shift = ((plen+Dbits)/Dbits)*Dbits;
        // in libcrypt version, (int)(LENGTH(pub->p)*sizeof(NumType)*CHARBITS);

        if(out == nil)
                out = mpnew(0);
        pm1 = mpnew(0);
        m = mpnew(0);
        gamma = mpnew(0);
        delta = mpnew(0);
        mpmod(in, p, m);
        while(1){
                k = mprand(plen, genrandom, nil);
                if((mpcmp(mpone, k) <= 0) && (mpcmp(k, pm1) < 0))
                        break;
        }
        mpexp(alpha, k, p, gamma);
        mpexp(pub->key, k, p, delta);
        mpmul(m, delta, delta);
        mpmod(delta, p, delta);
        mpleft(gamma, shift, out);
        mpadd(delta, out, out);
        mpfree(pm1);
        mpfree(m);
        mpfree(k);
        mpfree(gamma);
        mpfree(delta);
        return out;
}