org.bouncycastle.util

Class BigIntegers

java.lang.Object

org.bouncycastle.util.BigIntegers

public final class BigIntegers
extends Object

BigInteger utilities.

Field Summary

Fields

Modifier and Type	Field and Description
static BigInteger	ONE
static BigInteger	ZERO

Constructor Summary

Constructors

Constructor and Description
BigIntegers()

Method Summary

Modifier and Type	Method and Description
static byte[]	asUnsignedByteArray(BigInteger value) Return the passed in value as an unsigned byte array.
static byte[]	asUnsignedByteArray(int length, BigInteger value) Return the passed in value as an unsigned byte array.
static BigInteger	createRandomBigInteger(int bitLength, SecureRandom random) Return a positive BigInteger in the range of 0 to 2**bitLength - 1.
static BigInteger	createRandomInRange(BigInteger min, BigInteger max, SecureRandom random) Return a random BigInteger not less than 'min' and not greater than 'max'
static BigInteger	createRandomPrime(int bitLength, int certainty, SecureRandom random) Return a prime number candidate of the specified bit length.
static BigInteger	fromUnsignedByteArray(byte[] buf)
static BigInteger	fromUnsignedByteArray(byte[] buf, int off, int length)
static int	getUnsignedByteLength(BigInteger n)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

ZERO

public static final BigInteger ZERO

ONE

public static final BigInteger ONE

Constructor Detail

BigIntegers

public BigIntegers()

Method Detail

asUnsignedByteArray

public static byte[] asUnsignedByteArray(BigInteger value)

Return the passed in value as an unsigned byte array.

Parameters:

value - value to be converted.

Returns:

a byte array without a leading zero byte if present in the signed encoding.

asUnsignedByteArray

public static byte[] asUnsignedByteArray(int length,
                                         BigInteger value)

Return the passed in value as an unsigned byte array.

Parameters:

value - value to be converted.

Returns:

a byte array without a leading zero byte if present in the signed encoding.

createRandomInRange

public static BigInteger createRandomInRange(BigInteger min,
                                             BigInteger max,
                                             SecureRandom random)

Return a random BigInteger not less than 'min' and not greater than 'max'

Parameters:

min - the least value that may be generated

max - the greatest value that may be generated

random - the source of randomness

Returns:

a random BigInteger value in the range [min,max]

fromUnsignedByteArray

public static BigInteger fromUnsignedByteArray(byte[] buf)

fromUnsignedByteArray

public static BigInteger fromUnsignedByteArray(byte[] buf,
                                               int off,
                                               int length)

getUnsignedByteLength

public static int getUnsignedByteLength(BigInteger n)

createRandomBigInteger

public static BigInteger createRandomBigInteger(int bitLength,
                                                SecureRandom random)

Return a positive BigInteger in the range of 0 to 2**bitLength - 1.

Parameters:

bitLength - maximum bit length for the generated BigInteger.

random - a source of randomness.

Returns:

a positive BigInteger

createRandomPrime

public static BigInteger createRandomPrime(int bitLength,
                                           int certainty,
                                           SecureRandom random)

Return a prime number candidate of the specified bit length.

Parameters:

bitLength - bit length for the generated BigInteger.

random - a source of randomness.

Returns:

a positive BigInteger of numBits length