diff options
Diffstat (limited to 'src/libsec/port/egdecrypt.c')
-rw-r--r-- | src/libsec/port/egdecrypt.c | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/src/libsec/port/egdecrypt.c b/src/libsec/port/egdecrypt.c new file mode 100644 index 00000000..24578800 --- /dev/null +++ b/src/libsec/port/egdecrypt.c @@ -0,0 +1,28 @@ +#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; +} |