Large Integer Computing - Introduction to Cryptography with Java Applets - page 58

• public BigInteger setBit(int n) throws ArithmeticException

This method returns a BigInteger whose value is equivalent to this number with the des-
ignated bit set. It throws an ArithmeticException if n < 0.

• public BigInteger clearBit(int n) throws ArithmeticException

This method returns a BigInteger whose value is equivalent to this number with the des-

ignated bit cleared. It throws an ArithmeticException if n < 0.

• public BigInteger flipBit(int n) throws ArithmeticException

This method returns a BigInteger whose value is equivalent to this number with the des-

ignated bit flipped. It throws an ArithmeticException if n < 0.

• public int getLowestSetBit()

This method returns the index of the rightmost (lowest - order) one bit in this number
(that is, the number of zero bits to the right of the rightmost one bit). It returns 1 if this
number contains no one bits.

• public int bitLength()

This method returns the number of bits in the minimal two ' s - complement representation
of this number, excluding a sign bit. For positive numbers, this is equivalent to the number
of bits in the ordinary binary representation.

• public int bitCount()

this
number that differ from its sign bit. This method is useful when implementing bit-vector style
sets atop BigIntegers.

This method returns the number of bits in the two ' s - complement representation of

• public boolean isProbablePrime(int certainty)

this '

s definitely com-
posite. The certainty parameter is a measure of the uncertainty that the caller is willing to
tolerate: the method returns true if the probability that

This method returns true if BigInteger is probably prime, or false if it

this

1/2 t

number is prime exceeds 1

t

where = certainty. The execution time is proportional to the value of the certainty parameter.

The test for primality here is the same one used in the constructor that generates random prob-
able primes.

• public int compareTo(BigInteger val)

This method returns 1, 0, or 1 as this number is less than, equal to, or greater than val.
This method is provided in preference to individual methods for each of the six boolean
comparison operators:

==
!=
<