org.spongycastle.pqc.crypto.ntru

Class NTRUEngine

java.lang.Object

org.spongycastle.pqc.crypto.ntru.NTRUEngine

All Implemented Interfaces:

AsymmetricBlockCipher

public class NTRUEngine
extends java.lang.Object
implements AsymmetricBlockCipher

Encrypts, decrypts data and generates key pairs.
The parameter p is hardcoded to 3.

Constructor Summary

Constructors

Constructor and Description
NTRUEngine() Constructs a new instance with a set of encryption parameters.

Method Summary

Modifier and Type	Method and Description
protected IntegerPolynomial	decrypt(IntegerPolynomial e, Polynomial priv_t, IntegerPolynomial priv_fp)
protected IntegerPolynomial	encrypt(IntegerPolynomial m, TernaryPolynomial r, IntegerPolynomial pubKey)
int	getInputBlockSize() returns the largest size an input block can be.
int	getOutputBlockSize() returns the maximum size of the block produced by this cipher.
void	init(boolean forEncryption, CipherParameters parameters) initialise the cipher.
byte[]	processBlock(byte[] in, int inOff, int len) process the block of len bytes stored in in from offset inOff.

Methods inherited from class java.lang.Object

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

Constructor Detail

NTRUEngine

public NTRUEngine()

Constructs a new instance with a set of encryption parameters.

Method Detail

init

public void init(boolean forEncryption,
                 CipherParameters parameters)

Description copied from interface: AsymmetricBlockCipher

initialise the cipher.

Specified by:

init in interface AsymmetricBlockCipher

Parameters:

forEncryption - if true the cipher is initialised for encryption, if false for decryption.

parameters - the key and other data required by the cipher.

getInputBlockSize

public int getInputBlockSize()

Description copied from interface: AsymmetricBlockCipher

returns the largest size an input block can be.

Specified by:

getInputBlockSize in interface AsymmetricBlockCipher

Returns:

maximum size for an input block.

getOutputBlockSize

public int getOutputBlockSize()

Description copied from interface: AsymmetricBlockCipher

returns the maximum size of the block produced by this cipher.

Specified by:

getOutputBlockSize in interface AsymmetricBlockCipher

Returns:

maximum size of the output block produced by the cipher.

processBlock

public byte[] processBlock(byte[] in,
                           int inOff,
                           int len)
                    throws InvalidCipherTextException

Description copied from interface: AsymmetricBlockCipher

process the block of len bytes stored in in from offset inOff.

Specified by:

processBlock in interface AsymmetricBlockCipher

Parameters:

in - the input data

inOff - offset into the in array where the data starts

len - the length of the block to be processed.

Returns:

the resulting byte array of the encryption/decryption process.

Throws:

InvalidCipherTextException - data decrypts improperly.

encrypt

protected IntegerPolynomial encrypt(IntegerPolynomial m,
                                    TernaryPolynomial r,
                                    IntegerPolynomial pubKey)

decrypt

protected IntegerPolynomial decrypt(IntegerPolynomial e,
                                    Polynomial priv_t,
                                    IntegerPolynomial priv_fp)

Parameters:

e -

priv_t - a polynomial such that if fastFp=true, f=1+3*priv_t; otherwise, f=priv_t

priv_fp -

Returns:

an IntegerPolynomial representing the output.