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

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

protected int	l Length of the secret
protected java.security.SecureRandom	random

Constructor Summary

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

static ShamirSecretSplitter	getInstance(ShamirSecretSplitter.Algorithm algorithm, int l, java.security.SecureRandom random) Create a splitter using constant-time GF(256) arithmetic.
SplitSecret	resplit(byte[] secret, int m, int n) Creates secret shares from a given secret.
SplitSecret	split(int m, int n) Creates secret shares.
SplitSecret	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

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 SplitSecret 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 SplitSecret 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

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. The first of them is s.

Throws:

java.io.IOException

resplit

public SplitSecret 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

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.