// Convert a big integer to a base 64 string
private string bigint_to_b64(BigInteger bi)
{
byte[] b = bi.getBytes();
return Convert.ToBase64String(b);
}
// Perform an RSA public key operation on input
public byte[] DoPublic(byte[] input)
{
if (input.Length != this.keylen)
throw new ArgumentException("input.Length does not match keylen");
if (ReferenceEquals(this.N, null))
throw new ArgumentException("no key set!");
BigInteger T = new BigInteger(input);
if (T >= this.N)
throw new ArgumentException("input exceeds modulus");
T = T.modPow(this.E, this.N);
byte[] b = T.getBytes();
return pad_bytes(b, this.keylen);
}
