/* RSA encryption with the public key */
public static void ENCRYPT(rsa_public_key PUB, sbyte[] F, sbyte[] G)
{
int n = PUB.n.getlen();
FF f = new FF(n);
FF.fromBytes(f, F);
f.power(PUB.e, PUB.n);
f.toBytes(G);
}
public static void Main(string[] args)
{
int i;
int RFS = RSA.RFS;
string message = "Hello World\n";
rsa_public_key pub = new rsa_public_key(ROM.FFLEN);
rsa_private_key priv = new rsa_private_key(ROM.HFLEN);
sbyte[] ML = new sbyte[RFS];
sbyte[] C = new sbyte[RFS];
sbyte[] RAW = new sbyte[100];
RAND rng = new RAND();
rng.clean();
for (i = 0; i < 100; i++)
{
RAW[i] = (sbyte)(i);
}
rng.seed(100, RAW);
//for (i=0;i<10;i++)
//{
Console.WriteLine("Generating public/private key pair");
RSA.KEY_PAIR(rng, 65537, priv, pub);
sbyte[] M = message.GetBytes();
Console.Write("Encrypting test string\n");
sbyte[] E = RSA.OAEP_ENCODE(M, rng, null); // OAEP encode message M to E
RSA.ENCRYPT(pub, E, C); // encrypt encoded message
Console.Write("Ciphertext= 0x");
RSA.printBinary(C);
Console.Write("Decrypting test string\n");
RSA.DECRYPT(priv, C, ML);
sbyte[] MS = RSA.OAEP_DECODE(null, ML); // OAEP decode message
message = StringHelperClass.NewString(MS);
Console.Write(message);
//}
RSA.PRIVATE_KEY_KILL(priv);
}
/* generate an RSA key pair */
public static void KEY_PAIR(RAND rng, int e, rsa_private_key PRIV, rsa_public_key PUB)
{ // IEEE1363 A16.11/A16.12 more or less
int n = PUB.n.getlen() / 2;
FF t = new FF(n);
FF p1 = new FF(n);
FF q1 = new FF(n);
for (;;)
{
PRIV.p.random(rng);
while (PRIV.p.lastbits(2) != 3)
{
PRIV.p.inc(1);
}
while (!FF.prime(PRIV.p, rng))
{
PRIV.p.inc(4);
}
p1.copy(PRIV.p);
p1.dec(1);
if (p1.cfactor(e))
{
continue;
}
break;
}
for (;;)
{
PRIV.q.random(rng);
while (PRIV.q.lastbits(2) != 3)
{
PRIV.q.inc(1);
}
while (!FF.prime(PRIV.q, rng))
{
PRIV.q.inc(4);
}
q1.copy(PRIV.q);
q1.dec(1);
if (q1.cfactor(e))
{
continue;
}
break;
}
PUB.n = FF.mul(PRIV.p, PRIV.q);
PUB.e = e;
t.copy(p1);
t.shr();
PRIV.dp.set(e);
PRIV.dp.invmodp(t);
if (PRIV.dp.parity() == 0)
{
PRIV.dp.add(t);
}
PRIV.dp.norm();
t.copy(q1);
t.shr();
PRIV.dq.set(e);
PRIV.dq.invmodp(t);
if (PRIV.dq.parity() == 0)
{
PRIV.dq.add(t);
}
PRIV.dq.norm();
PRIV.c.copy(PRIV.p);
PRIV.c.invmodp(PRIV.q);
return;
}
