/**
* Creates a rational number of the specified {@link BigInteger} value.
*
* @param value the {@link BigInteger} value
* @return the rational number
*/
public static BigRational valueOf(BigInteger value)
{
if (value.compareTo(BigInteger.ZERO) == 0)
{
return(ZERO);
}
if (value.compareTo(BigInteger.ONE) == 0)
{
return(ONE);
}
return(valueOf(value, BigInteger.ONE));
}
private static byte[] encryptBlock(byte[] block, BigInteger n)
{
BigInteger blockInt = new BigInteger(block);
if (blockInt.compareTo(BigInteger.ZERO) < 0)
{
blockInt = blockInt.modPow(E, n);
return blockInt.multiply(BigInteger.valueOf(-1)).toByteArray();
}
else
{
return (blockInt).modPow(E, n).toByteArray();
}
}
private static bool runMillerRabin(BigInteger number, SecureRandom random
)
{
if (number.compareTo(BigInteger.valueOf(3)) <= 0)
{
return number.compareTo(BigInteger.ONE) != 0;
}
// Ensures that temp > 1 and temp < n.
BigInteger temp = BigInteger.ZERO;
do
{
temp = new BigInteger(number.bitLength() - 1, random);
}
while (temp.compareTo(BigInteger.ONE) <= 0);
// Screen out n if our random number happens to share a factor with n.
if (!number.gcd(temp).Equals(BigInteger.ONE))
{
return false;
}
// For debugging, prints out the integer to test with.
//System.out.println("Testing with " + temp);
BigInteger d = number.subtract(BigInteger.ONE);
// Figure s and d Values
int s = 0;
while ((d.mod(TWO)).Equals(BigInteger.ZERO))
{
d = d.divide(TWO);
s++;
}
BigInteger curValue = temp.modPow(d, number);
// If this works out, it's a prime
if (curValue.Equals(BigInteger.ONE))
{
return true;
}
// Otherwise, we will check to see if this value successively
// squared ever yields -1.
for (int r = 0; r < s; r++)
{
// We need to really check n-1 which is equivalent to -1.
if (curValue.Equals(number.subtract(BigInteger.ONE)))
{
return true;
}
else
{
// Square this previous number - here I am just doubling the
// exponent. A more efficient implementation would store the
// value of the exponentiation and square it mod n.
curValue = curValue.modPow(TWO, number);
}
}
// If none of our tests pass, we return false. The number is
// definitively composite if we ever get here.
return false;
}
