de.flexiprovider.pqc.ecc.niederreiter
Class NiederreiterPKCS

java.lang.Object
  |
  +--javax.crypto.CipherSpi
        |
        +--de.flexiprovider.api.Cipher
              |
              +--de.flexiprovider.api.AsymmetricBlockCipher
                    |
                    +--de.flexiprovider.pqc.ecc.niederreiter.NiederreiterPKCS

public class NiederreiterPKCS

extends AsymmetricBlockCipher

This class implements the Niederreiter Public Key Cryptosystem which is based on error correcting codes. The class extends de.flexiprovider.common.cipher.AsymmetricBasicCipher.

The NiederreiterPKC can be used as follows:

To encrypt a message, the following steps have to be performed:

 // The message which should be encrypted
 String message = "secret message";
 byte[] messageBytes = message.getBytes();
 
 // Generate KeySpec from encoded Niederreiter public key:
 KeySpec publicKeySpec = new X509EncodedKeySpec(encPublicKey);
 
 // Initialize the Niederreiter key factory:<br/>
 KeyFactory keyFactory = KeyFactory.getInstance("Niederreiter", "FlexiPQC");
 
 // Decode Niederreiter public key:<br/>
 PublicKey publicKey = keyFactory.generatePublic(publicKeySpec);
 
 // The source of randomness
 SecureRandom sr = Registry.getSecureRandom();
 
 // Obtain a NiederreiterPKC Cipher Object
 Cipher cipher = Cipher.getInstance("NiederreiterPKCS");
 
 // Initialize the cipher
 cipher.init(Cipher.ENCRYPT_MODE, publicKey, sr);
 
 // Finally encrypt the message
 byte[] ciphertextBytes = cipher.doFinal(messageBytes);
 

To decrypt a message, the following steps have to be performed:

 // Generate KeySpec from encoded Niederreiter private key:
 KeySpec publicKeySpec = new PKCS8EncodedKeySpec(encPrivateKey);
 
 // Initialize the Niederreiter key factory:<br/>
 KeyFactory keyFactory = KeyFactory.getInstance("Niederreiter", "FlexiPQC");
 
 // Decode Niederreiter private key:<br/>
 PublicKey privateKey = keyFactory.generatePrivate(privateKeySpec);
 
 // Obtain a NiederreiterPKC Cipher Object
 Cipher cipher = Cipher.getInstance("NiederreiterPKCS");
 
 // Initialize the cipher
 cipher.init(Cipher.DECRYPT_MODE, privateKey);
 
 // Finally decrypt the message
 byte[] messageBytes = cipher.doFinal(ciphertextBytes);
 String message = new String(messageBytes);
 

Author:

Elena Klintsevich

See Also:

AsymmetricBlockCipher

Field Summary

static java.lang.String

OID The OID of the algorithm.

Fields inherited from class de.flexiprovider.api.AsymmetricBlockCipher

buf, cipherTextSize, maxPlainTextSize, paramSpec

Fields inherited from class de.flexiprovider.api.Cipher

DECRYPT_MODE, ENCRYPT_MODE, opMode

Constructor Summary

NiederreiterPKCS()

Method Summary

int	getKeySize(Key key) Return the key size of the given key object.
java.lang.String	getName() Return the name of this cipher.
protected void	initCipherDecrypt(Key key, AlgorithmParameterSpec params) Initialize the cipher with a private key and parameters for decryption.
protected void	initCipherEncrypt(Key key, AlgorithmParameterSpec params, SecureRandom secureRandom) Initialize the cipher with a public key and parameters for encryption.
protected byte[]	messageDecrypt(byte[] input) Decrypt a ciphertext given in input.
protected byte[]	messageEncrypt(byte[] input) Encrypt a plaintext given in input.

Methods inherited from class de.flexiprovider.api.AsymmetricBlockCipher

checkLength, doFinal, doFinal, getBlockSize, getIV, getOutputSize, getParameters, initDecrypt, initDecrypt, initEncrypt, initEncrypt, initEncrypt, initEncrypt, setMode, setPadding, update, update

Methods inherited from class de.flexiprovider.api.Cipher

doFinal, doFinal, engineDoFinal, engineDoFinal, engineGetBlockSize, engineGetIV, engineGetKeySize, engineGetOutputSize, engineGetParameters, engineInit, engineInit, engineInit, engineSetMode, engineSetPadding, engineUpdate, engineUpdate, update

Methods inherited from class java.lang.Object

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

Field Detail

OID

public static final java.lang.String OID

The OID of the algorithm.

Constructor Detail

NiederreiterPKCS

public NiederreiterPKCS()

Method Detail

getName

public java.lang.String getName()

Return the name of this cipher.

Overrides:

getName in class Cipher

Returns:

"Niederreiter"

getKeySize

public int getKeySize(Key key)
               throws InvalidKeyException

Return the key size of the given key object. Checks whether the key object is an instance of NiederreiterPublicKey or NiederreiterPrivateKey.

Overrides:

getKeySize in class Cipher

Parameters:

key - the key object

Returns:

the key size of the given key object

Throws:

InvalidKeyException - if the key is invalid

initCipherEncrypt

protected void initCipherEncrypt(Key key,
                                 AlgorithmParameterSpec params,
                                 SecureRandom secureRandom)
                          throws InvalidKeyException

Initialize the cipher with a public key and parameters for encryption.

Overrides:

initCipherEncrypt in class AsymmetricBlockCipher

Parameters:

key - the key to use for encryption

params - the algorithm parameters

secureRandom - the source of randomness

Throws:

InvalidKeyException - if the given key is inappropriate for initializing this cipher.

initCipherDecrypt

protected void initCipherDecrypt(Key key,
                                 AlgorithmParameterSpec params)
                          throws InvalidKeyException

Initialize the cipher with a private key and parameters for decryption.

Overrides:

initCipherDecrypt in class AsymmetricBlockCipher

Parameters:

key - the key to use for decryption

params - the algorithm parameters

Throws:

InvalidKeyException - if the given key is inappropriate for initializing this cipher.

messageEncrypt

protected byte[] messageEncrypt(byte[] input)

Encrypt a plaintext given in input.

Overrides:

messageEncrypt in class AsymmetricBlockCipher

Parameters:

input - the plaintext

Returns:

the ciphertext

messageDecrypt

protected byte[] messageDecrypt(byte[] input)
                         throws BadPaddingException

Decrypt a ciphertext given in input.

Overrides:

messageDecrypt in class AsymmetricBlockCipher

Parameters:

input - the ciphertext

Returns:

the plaintext

Throws:

BadPaddingException - if the ciphertext is invalid.