org.bouncycastle.util
Class BigIntegers

java.lang.Object
  |
  +--org.bouncycastle.util.BigIntegers

public final class BigIntegers

extends java.lang.Object

BigInteger utilities.

Inner Class Summary

static class

BigIntegers.Cache

Field Summary

static java.math.BigInteger	ONE
static java.math.BigInteger	TWO
static java.math.BigInteger	ZERO

Constructor Summary

BigIntegers()

Method Summary

static byte[]	asUnsignedByteArray(java.math.BigInteger value) Return the passed in value as an unsigned byte array.
static void	asUnsignedByteArray(java.math.BigInteger value, byte[] buf, int off, int len) Write the passed in value as unsigned bytes to the specified buffer range, padded with leading zeros as necessary.
static byte[]	asUnsignedByteArray(int length, java.math.BigInteger value) Return the passed in value as an unsigned byte array of the specified length, padded with leading zeros as necessary..
static byte	byteValueExact(java.math.BigInteger x)
static java.math.BigInteger	createRandomBigInteger(int bitLength, java.security.SecureRandom random) Return a positive BigInteger in the range of 0 to 2**bitLength - 1.
static java.math.BigInteger	createRandomInRange(java.math.BigInteger min, java.math.BigInteger max, java.security.SecureRandom random) Return a random BigInteger not less than 'min' and not greater than 'max'
static java.math.BigInteger	createRandomPrime(int bitLength, int certainty, java.security.SecureRandom random) Return a prime number candidate of the specified bit length.
static java.math.BigInteger	fromUnsignedByteArray(byte[] buf)
static java.math.BigInteger	fromUnsignedByteArray(byte[] buf, int off, int length)
static int	getUnsignedByteLength(java.math.BigInteger n)
static int	intValueExact(java.math.BigInteger x)
static long	longValueExact(java.math.BigInteger x)
static java.math.BigInteger	modOddInverse(java.math.BigInteger M, java.math.BigInteger X)
static java.math.BigInteger	modOddInverseVar(java.math.BigInteger M, java.math.BigInteger X)
static short	shortValueExact(java.math.BigInteger x)

Methods inherited from class java.lang.Object

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

Field Detail

ZERO

public static final java.math.BigInteger ZERO

ONE

public static final java.math.BigInteger ONE

TWO

public static final java.math.BigInteger TWO

Constructor Detail

BigIntegers

public BigIntegers()

Method Detail

asUnsignedByteArray

public static byte[] asUnsignedByteArray(java.math.BigInteger value)

Return the passed in value as an unsigned byte array.

Parameters:

value - the 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,
                                         java.math.BigInteger value)

Return the passed in value as an unsigned byte array of the specified length, padded with leading zeros as necessary..

Parameters:

length - the fixed length of the result

value - the value to be converted.

Returns:

a byte array padded to a fixed length with leading zeros.

asUnsignedByteArray

public static void asUnsignedByteArray(java.math.BigInteger value,
                                       byte[] buf,
                                       int off,
                                       int len)

Write the passed in value as unsigned bytes to the specified buffer range, padded with leading zeros as necessary.

Parameters:

value - the value to be converted.

buf - the buffer to which the value is written.

off - the start offset in array buf at which the data is written.

len - the fixed length of data written (possibly padded with leading zeros).

createRandomInRange

public static java.math.BigInteger createRandomInRange(java.math.BigInteger min,
                                                       java.math.BigInteger max,
                                                       java.security.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 java.math.BigInteger fromUnsignedByteArray(byte[] buf)

fromUnsignedByteArray

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

byteValueExact

public static byte byteValueExact(java.math.BigInteger x)

shortValueExact

public static short shortValueExact(java.math.BigInteger x)

intValueExact

public static int intValueExact(java.math.BigInteger x)

longValueExact

public static long longValueExact(java.math.BigInteger x)

modOddInverse

public static java.math.BigInteger modOddInverse(java.math.BigInteger M,
                                                 java.math.BigInteger X)

modOddInverseVar

public static java.math.BigInteger modOddInverseVar(java.math.BigInteger M,
                                                    java.math.BigInteger X)

getUnsignedByteLength

public static int getUnsignedByteLength(java.math.BigInteger n)

createRandomBigInteger

public static java.math.BigInteger createRandomBigInteger(int bitLength,
                                                          java.security.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 java.math.BigInteger createRandomPrime(int bitLength,
                                                     int certainty,
                                                     java.security.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