| rsc | 0fc65b3 | 2004-03-21 14:04:56 +0000 | [diff] [blame] | 1 | #include "os.h" |
| 2 | #include <mp.h> |
| 3 | #include <libsec.h> |
| 4 | |
| 5 | mpint* |
| 6 | egdecrypt(EGpriv *priv, mpint *in, mpint *out) |
| 7 | { |
| 8 | EGpub *pub = &priv->pub; |
| 9 | mpint *gamma, *delta; |
| 10 | mpint *p = pub->p; |
| 11 | int plen = mpsignif(p)+1; |
| 12 | int shift = ((plen+Dbits-1)/Dbits)*Dbits; |
| 13 | |
| 14 | if(out == nil) |
| 15 | out = mpnew(0); |
| 16 | gamma = mpnew(0); |
| 17 | delta = mpnew(0); |
| 18 | mpright(in, shift, gamma); |
| 19 | mpleft(gamma, shift, delta); |
| 20 | mpsub(in, delta, delta); |
| 21 | mpexp(gamma, priv->secret, p, out); |
| 22 | mpinvert(out, p, gamma); |
| 23 | mpmul(gamma, delta, out); |
| 24 | mpmod(out, p, out); |
| 25 | mpfree(gamma); |
| 26 | mpfree(delta); |
| 27 | return out; |
| 28 | } |
