org.bouncycastle.util

Class BigIntegers

java.lang.Object

org.bouncycastle.util.BigIntegers

public final class BigIntegers
extends java.lang.Object

BigInteger utilities.

Field Summary

Fields

Modifier and Type	Field and Description
static java.math.BigInteger	ONE
static java.math.BigInteger	ZERO

Constructor Summary

Constructors

Constructor and Description
BigIntegers()

Method Summary

Modifier and Type	Method and Description
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 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)

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

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)

intValueExact

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

longValueExact

public static long longValueExact(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