Package org.bouncycastle.util

Class BigIntegers

java.lang.Object

org.bouncycastle.util.BigIntegers

public final class BigIntegers
extends Object

BigInteger utilities.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	BigIntegers.Cache

Field Summary

Fields

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

Constructor Summary

Constructors

Constructor	Description
BigIntegers()

Method Summary

Modifier and Type	Method	Description
static byte[]	asUnsignedByteArray(int length, BigInteger value)	Return the passed in value as an unsigned byte array of the specified length, padded with leading zeros as necessary..
static byte[]	asUnsignedByteArray(BigInteger value)	Return the passed in value as an unsigned byte array.
static void	asUnsignedByteArray(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[]	asUnsignedByteArrayAlign32(BigInteger value)	Return the passed in value as an unsigned byte array rounded to mod unit long.
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)
static int	intValueExact(BigInteger x)
static long	longValueExact(BigInteger x)
static BigInteger	modOddInverse(BigInteger M, BigInteger X)
static BigInteger	modOddInverseVar(BigInteger M, BigInteger X)

Methods inherited from class java.lang.Object

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

Field Details

ZERO

public static final BigInteger ZERO

ONE

public static final BigInteger ONE

TWO

public static final BigInteger TWO

Constructor Details

BigIntegers

public BigIntegers()

Method Details

asUnsignedByteArrayAlign32

public static byte[] asUnsignedByteArrayAlign32(BigInteger value)

Return the passed in value as an unsigned byte array rounded to mod unit long.

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(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,
 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(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 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)

intValueExact

public static int intValueExact(BigInteger x)

longValueExact

public static long longValueExact(BigInteger x)

modOddInverse

public static BigInteger modOddInverse(BigInteger M,
 BigInteger X)

modOddInverseVar

public static BigInteger modOddInverseVar(BigInteger M,
 BigInteger X)

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