mirror of https://github.com/0intro/conterm
39 lines
806 B
C
39 lines
806 B
C
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#include "os.h"
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#include <mp.h>
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#include <libsec.h>
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mpint*
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egencrypt(EGpub *pub, mpint *in, mpint *out)
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{
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mpint *m, *k, *gamma, *delta, *pm1;
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mpint *p = pub->p, *alpha = pub->alpha;
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int plen = mpsignif(p);
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int shift = ((plen+Dbits)/Dbits)*Dbits;
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// in libcrypt version, (int)(LENGTH(pub->p)*sizeof(NumType)*CHARBITS);
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if(out == nil)
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out = mpnew(0);
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pm1 = mpnew(0);
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m = mpnew(0);
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gamma = mpnew(0);
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delta = mpnew(0);
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mpmod(in, p, m);
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while(1){
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k = mprand(plen, genrandom, nil);
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if((mpcmp(mpone, k) <= 0) && (mpcmp(k, pm1) < 0))
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break;
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}
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mpexp(alpha, k, p, gamma);
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mpexp(pub->key, k, p, delta);
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mpmul(m, delta, delta);
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mpmod(delta, p, delta);
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mpleft(gamma, shift, out);
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mpadd(delta, out, out);
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mpfree(pm1);
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mpfree(m);
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mpfree(k);
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mpfree(gamma);
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mpfree(delta);
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return out;
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}
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