public Class WinternitzOTSVerify

Class Inheritance

extends Object

java.lang.Object
org.bouncycastle.pqc.legacy.crypto.gmss.util.WinternitzOTSVerify

Imports

org.bouncycastle.crypto.Digest

This class implements signature verification of the Winternitz one-time signature scheme (OTSS), described in C.Dods, N.P. Smart, and M. Stam, "Hash Based Digital Signature Schemes", LNCS 3796, pages 96–115, 2005. The class is used by the GMSS classes.

Field Summary

Modifier and Type	Field and Description
private int	mdsize
private Digest	messDigestOTS
private int	w The Winternitz parameter

Constructor Summary

Access	Constructor and Description
public	WinternitzOTSVerify(Digest the name of the hash function used by the OTS and the provider name of the hash function digest, int the Winternitz parameter w) The constructor

Method Summary

Modifier and Type	Method and Description
public int	Returns: The least integer greater or equal to the logarithm to the base 256 of `intValue` getLog(int an integer intValue) This method returns the least integer that is greater or equal to the logarithm to the base 2 of an integer `intValue`.
public int	Returns: The length of the one-time signature getSignatureLength()
private void	hashSignatureBlock(byte[] sig, int sigOff, int rounds, byte[] buf, int bufOff)
public byte[]	Returns: The public OTS key Verify(byte[] the message message, byte[] the one-time signature signature) This method computes the public OTS key from the one-time signature of a message.

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

Field Detail

mdsize	back to summary
private int mdsize

messDigestOTS	back to summary
private Digest messDigestOTS

w	back to summary
private int w The Winternitz parameter

Constructor Detail

WinternitzOTSVerify	back to summary
public WinternitzOTSVerify(Digest digest, int w) The constructor Parameters digest:Digest the name of the hash function used by the OTS and the provider name of the hash function w:int the Winternitz parameter

WinternitzOTSVerify

back to summary

public WinternitzOTSVerify(Digest digest, int w)

The constructor

Parameters

digest:Digest: the name of the hash function used by the OTS and the provider name of the hash function
w:int: the Winternitz parameter

Method Detail

getLog back to summary

getLog	back to summary
public int getLog(int intValue) This method returns the least integer that is greater or equal to the logarithm to the base 2 of an integer `intValue`. Parameters intValue:int an integer Returns:int The least integer greater or equal to the logarithm to the base 256 of `intValue`

public int getLog(int intValue)

This method returns the least integer that is greater or equal to the logarithm to the base 2 of an integer intValue.

Parameters

intValue:int: an integer

Returns:int

The least integer greater or equal to the logarithm to the base 256 of intValue

getSignatureLength	back to summary
public int getSignatureLength() Returns:int The length of the one-time signature

hashSignatureBlock	back to summary
private void hashSignatureBlock(byte[] sig, int sigOff, int rounds, byte[] buf, int bufOff)

Verify	back to summary
public byte[] Verify(byte[] message, byte[] signature) This method computes the public OTS key from the one-time signature of a message. This is NOT a complete OTS signature verification, but it suffices for usage with CMSS. Parameters message:byte[] the message signature:byte[] the one-time signature Returns:byte[] The public OTS key

Verify

back to summary

public byte[] Verify(byte[] message, byte[] signature)

This method computes the public OTS key from the one-time signature of a message. This is *NOT* a complete OTS signature verification, but it suffices for usage with CMSS.

Parameters

message:byte[]: the message
signature:byte[]: the one-time signature

Returns:byte[]

The public OTS key