nxt.crypto

Class SecretSharingGenerator

java.lang.Object

nxt.crypto.SecretSharingGenerator

public class SecretSharingGenerator
extends java.lang.Object

Constructor Summary

Constructors

Constructor and Description
SecretSharingGenerator()

Method Summary

Modifier and Type	Method and Description
static java.lang.String	combine(java.lang.String[] encodedSecretPhrasePieces) Given minPieces pieces out of totalPieces of a secretPhrase, combine the pieces into the original phrase.* Pieces are formatted as [version]:[split id]:[total pieces]:[minimum pieces]:[prime field size or zero]:[piece number]:[piece content]
static byte[]	combinePrivateKey(java.lang.String[] encodedSecretPhrasePieces) Given minPieces pieces out of totalPieces of a privateKey, combine the pieces into the original.
static java.math.BigInteger	getModPrime(byte[] privateKey) Given a private key calculate the modulo prime finite field size which is sufficiently large to split the key.
static java.math.BigInteger	getModPrime(java.lang.String secretPhrase) Given a secret phrase calculate the modulo prime finite field size which is sufficiently large to split the shared secrets.
static boolean	isPrivateKeySecret(java.lang.String[] encodedSecretPhrasePieces)
static java.lang.String[]	split(byte[] privateKey, int totalPieces, int minPieces, java.math.BigInteger declaredModePrime) Given a secret byte array split it into totalPieces pieces where each minPieces of them are enough to reproduce the secret.
static java.lang.String[]	split(java.lang.String secretPhrase, int totalPieces, int minPieces, java.math.BigInteger declaredModePrime) Given a secretPhrase split it into totalPieces pieces where each minPieces of them are enough to reproduce the secret.

Methods inherited from class java.lang.Object

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

Constructor Detail

SecretSharingGenerator

public SecretSharingGenerator()

Method Detail

split

public static java.lang.String[] split(java.lang.String secretPhrase,
                                       int totalPieces,
                                       int minPieces,
                                       java.math.BigInteger declaredModePrime)

Given a secretPhrase split it into totalPieces pieces where each minPieces of them are enough to reproduce the secret. If the secret phrase a is valid BIP39 mnemonic using the english wordlist, it is converted to the corresponding entropy between 128 and 256 bits and a byte to store the number of words on the original mnemonic. If the secret phrase is 12 words from the legacy list, the secret is converted into 128 bit number which is very compact. Otherwise the secret phrase is converted to bytes using UTF8 then to a BigInteger. Every one of these cases is codified into the version integer of the resulting pieces. Pieces are returned with a piece number followed by : and the piece content. The piece number is required when reproducing the secret.

Parameters:

secretPhrase - the secret phrase

totalPieces - the number of generated pieces

minPieces - the number of pieces needed to reproduce the secret phrase

declaredModePrime - the modulo prime used for secret sharing calculations. Specify BigInteger.ZERO to calculate automatically

Returns:

the secret pieces

split

public static java.lang.String[] split(byte[] privateKey,
                                       int totalPieces,
                                       int minPieces,
                                       java.math.BigInteger declaredModePrime)

Given a secret byte array split it into totalPieces pieces where each minPieces of them are enough to reproduce the secret. Pieces are returned with a piece number followed by : and the piece content. The piece number is required when reproducing the secret.

Parameters:

privateKey - the secret byte array

totalPieces - the number of generated pieces

minPieces - the number of pieces needed to reproduce the secret phrase

declaredModePrime - the modulo prime used for secret sharing calculations. Specify BigInteger.ZERO to calculate automatically

Returns:

the secret pieces

combinePrivateKey

public static byte[] combinePrivateKey(java.lang.String[] encodedSecretPhrasePieces)

Given minPieces pieces out of totalPieces of a privateKey, combine the pieces into the original. Pieces are formatted as [version]:[split id]:[total pieces]:[minimum pieces]:[prime field size or zero]:[piece number]:[piece content]

Parameters:

encodedSecretPhrasePieces - the pieces of the private key formatted as specified above

Returns:

the reproduced private key

combine

public static java.lang.String combine(java.lang.String[] encodedSecretPhrasePieces)

Given minPieces pieces out of totalPieces of a secretPhrase, combine the pieces into the original phrase.* Pieces are formatted as [version]:[split id]:[total pieces]:[minimum pieces]:[prime field size or zero]:[piece number]:[piece content]

Parameters:

encodedSecretPhrasePieces - the pieces of the secret phrase formatted as specified above

Returns:

the reproduced secret phrase

isPrivateKeySecret

public static boolean isPrivateKeySecret(java.lang.String[] encodedSecretPhrasePieces)

getModPrime

public static java.math.BigInteger getModPrime(java.lang.String secretPhrase)

Given a secret phrase calculate the modulo prime finite field size which is sufficiently large to split the shared secrets. The specific encoding (version) used is guessed trying to find the best one.

Parameters:

secretPhrase - the secret phrase

Returns:

the prime number representing the finite field size

getModPrime

public static java.math.BigInteger getModPrime(byte[] privateKey)

Given a private key calculate the modulo prime finite field size which is sufficiently large to split the key.

Parameters:

privateKey - the private key

Returns:

the prime number representing the finite field size