org.bouncycastle.crypto.threshold

Class ShamirSecretSplitter

java.lang.Object

org.bouncycastle.crypto.threshold.ShamirSecretSplitter

All Implemented Interfaces:

SecretSplitter

public class ShamirSecretSplitter
extends java.lang.Object
implements SecretSplitter

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	ShamirSecretSplitter.Algorithm
static class	ShamirSecretSplitter.Mode Deprecated. no longer selects anything. Mode.Table indexed log/exp tables with the secret being split and with the share bytes, so which cache line it touched revealed them; both values now use the same constant-time arithmetic. Use getInstance(Algorithm, int, SecureRandom), which takes no mode.

Field Summary

Fields

Modifier and Type	Field and Description
protected int	l Length of the secret
protected java.security.SecureRandom	random

Constructor Summary

Constructors

Constructor and Description
ShamirSecretSplitter(ShamirSecretSplitter.Algorithm algorithm, ShamirSecretSplitter.Mode mode, int l, java.security.SecureRandom random) Deprecated. the mode is ignored - see ShamirSecretSplitter.Mode. Use getInstance(Algorithm, int, SecureRandom).

Method Summary

Modifier and Type	Method and Description
static ShamirSecretSplitter	getInstance(ShamirSecretSplitter.Algorithm algorithm, int l, java.security.SecureRandom random) Create a splitter using constant-time GF(256) arithmetic.
ShamirSplitSecret	resplit(byte[] secret, int m, int n) Creates secret shares from a given secret.
ShamirSplitSecret	split(int m, int n) Creates secret shares.
ShamirSplitSecret	splitAround(SecretShare s, int m, int n) Creates secret shares from a given secret share.

Methods inherited from class java.lang.Object

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

Field Detail

l

protected int l

Length of the secret

random

protected java.security.SecureRandom random

Constructor Detail

ShamirSecretSplitter

@Deprecated
public ShamirSecretSplitter(ShamirSecretSplitter.Algorithm algorithm,
                                        ShamirSecretSplitter.Mode mode,
                                        int l,
                                        java.security.SecureRandom random)

Deprecated. the mode is ignored - see ShamirSecretSplitter.Mode. Use getInstance(Algorithm, int, SecureRandom).

Method Detail

getInstance

public static ShamirSecretSplitter getInstance(ShamirSecretSplitter.Algorithm algorithm,
                                               int l,
                                               java.security.SecureRandom random)

Create a splitter using constant-time GF(256) arithmetic.

Parameters:

algorithm - the reduction polynomial to work over.

l - length in bytes of the secret to be split.

random - source of randomness for the polynomial coefficients.

split

public ShamirSplitSecret split(int m,
                               int n)

Description copied from interface: SecretSplitter

Creates secret shares. The secret will be divided into shares, where the secret has a length of L bytes.

Specified by:

split in interface SecretSplitter

Parameters:

m - A threshold number of shares

n - Total number of shares

Returns:

the n generated secret shares, each L bytes long, any m of which recover the secret.

splitAround

public ShamirSplitSecret splitAround(SecretShare s,
                                     int m,
                                     int n)
                              throws java.io.IOException

Description copied from interface: SecretSplitter

Creates secret shares from a given secret share. The secret will be divided into shares, where the secret has a length of L bytes.

Specified by:

splitAround in interface SecretSplitter

m - A threshold number of shares

n - Total number of shares

Returns:

the n generated secret shares, each L bytes long, any m of which recover the secret. The first of them is s.

Throws:

java.io.IOException

resplit

public ShamirSplitSecret resplit(byte[] secret,
                                 int m,
                                 int n)

Description copied from interface: SecretSplitter

Creates secret shares from a given secret. The secret will be divided into shares, where the secret has a length of L bytes.

Specified by:

resplit in interface SecretSplitter

m - A threshold number of shares

n - Total number of shares

Returns:

the n generated secret shares, each L bytes long, any m of which recover the secret.