ref: de19776b2f793de7fdf1111d84d96eb29f9a22fd
dir: /sys/src/libsec/port/egdecrypt.c/
#include "os.h" #include <mp.h> #include <libsec.h> mpint* egdecrypt(EGpriv *priv, mpint *in, mpint *out) { EGpub *pub = &priv->pub; mpint *gamma, *delta; mpint *p = pub->p; int plen = mpsignif(p)+1; int shift = ((plen+Dbits-1)/Dbits)*Dbits; if(out == nil) out = mpnew(0); gamma = mpnew(0); delta = mpnew(0); mpright(in, shift, gamma); mpleft(gamma, shift, delta); mpsub(in, delta, delta); mpexp(gamma, priv->secret, p, out); mpinvert(out, p, gamma); mpmul(gamma, delta, out); mpmod(out, p, out); mpfree(gamma); mpfree(delta); return out; }