edu.vt.middleware.crypt
Class AbstractEncryptionAlgorithm

java.lang.Object
  edu.vt.middleware.crypt.AbstractAlgorithm
      edu.vt.middleware.crypt.AbstractEncryptionAlgorithm

All Implemented Interfaces:

Algorithm, EncryptionAlgorithm

Direct Known Subclasses:

AsymmetricAlgorithm, SymmetricAlgorithm

public abstract class AbstractEncryptionAlgorithm
extends AbstractAlgorithm
implements EncryptionAlgorithm

Base class for symmetric and asymmetric encryption algorithms. This class is essentially a wrapper for the Cipher class.

Version:

$Revision: 3 $

Author:

Middleware Services

Field Summary

protected Cipher	cipher Encryption/decription cipher.
protected int	cipherMode Either Cipher.ENCRYPT_MODE or Cipher.DECRYPT_MODE.
protected Key	key Key used for encryption or decryption.
protected String	mode Mode used for encryption and decryption.
protected String	padding Padding used for encryption and decryption.

Fields inherited from class edu.vt.middleware.crypt.AbstractAlgorithm

algorithm, logger, randomByteSize, randomProvider

Constructor Summary

protected

AbstractEncryptionAlgorithm(String cipherAlgorithm, String cipherModeName, String cipherPadding) Creates a new encryption algorithm that uses a cipher of the given name.

Method Summary

protected byte[]	crypt(byte[] in) Based on current cipher mode, encrypts or decrypts the given input data.
protected void	crypt(InputStream in, OutputStream out) Based on current cipher mode, encrypts or decrypts the data in the given input stream into resulting data in the output stream.
byte[]	decrypt(byte[] ciphertext) Decrypts the given ciphertext bytes into a byte array of plaintext using the decryption key.
void	decrypt(InputStream in, OutputStream out) Decrypts the data in the given ciphertext input stream into plaintext in the output stream.
byte[]	decrypt(String ciphertext, Converter converter) Decrypts a string representation of ciphertext bytes into a byte array of plaintext using the decryption key.
byte[]	encrypt(byte[] plaintext) Encrypts the given plaintext bytes into a byte array of ciphertext using the encryption key.
String	encrypt(byte[] plaintext, Converter converter) Encrypts the given plaintext bytes into a ciphertext string using the conversion strategy provided by the given converter.
void	encrypt(InputStream in, OutputStream out) Encrypts the data in the given plaintext input stream into ciphertext in the output stream.
protected abstract AlgorithmParameterSpec	getAlgorithmParameterSpec() Gets the algorithm parameter specification for this algorithm.
int	getBlockSize() Gets the block size of the encryption algorithm cipher in bytes.
protected abstract int	getChunkSize() Gets the chunk size for buffers using in stream-based encryption and decryption operations.
int	getCipherMode() Gets the cipher mode indicating whether this instance is currently initialized for encryption or decryption.
String	getMode() Gets the encryption mode.
String	getPadding() Gets the encryption padding method.
protected void	init(int encryptOrDecrypt) Initializes cipher for either encryption or decryption.
protected void	initCipher() Initializes the underlying Cipher object using AbstractAlgorithm.algorithm, mode, and padding.
void	initDecrypt() Initializes this instance for decryption operations.
void	initEncrypt() Initializes this instance for encryption operations.
void	setKey(Key k) Sets the key used for encryption/decryption.
String	toString()

Methods inherited from class edu.vt.middleware.crypt.AbstractAlgorithm

getAlgorithm, getRandomData, setRandomProvider

Methods inherited from class java.lang.Object

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

Methods inherited from interface edu.vt.middleware.crypt.Algorithm

getAlgorithm, getRandomData, setRandomProvider

Field Detail

cipher

protected Cipher cipher

Encryption/decription cipher.

mode

protected String mode

Mode used for encryption and decryption.

padding

protected String padding

Padding used for encryption and decryption.

cipherMode

protected int cipherMode

Either Cipher.ENCRYPT_MODE or Cipher.DECRYPT_MODE.

key

protected Key key

Key used for encryption or decryption.

Constructor Detail

AbstractEncryptionAlgorithm

protected AbstractEncryptionAlgorithm(String cipherAlgorithm,
                                      String cipherModeName,
                                      String cipherPadding)

Creates a new encryption algorithm that uses a cipher of the given name.

Parameters:

cipherAlgorithm - Cipher algorithm name.

cipherModeName - Cipher mode.

cipherPadding - Cipher padding method.

Method Detail

getMode

public String getMode()

Gets the encryption mode.

Specified by:

getMode in interface EncryptionAlgorithm

Returns:

Name of an encryption mode, e.g. CBC.

getPadding

public String getPadding()

Gets the encryption padding method.

Specified by:

getPadding in interface EncryptionAlgorithm

Returns:

Name of a padding method, e.g. PKCS5Padding.

setKey

public void setKey(Key k)

Sets the key used for encryption/decryption.

Specified by:

setKey in interface EncryptionAlgorithm

Parameters:

k - Public, private, or secret key used for encryption or decryption.

getCipherMode

public int getCipherMode()

Gets the cipher mode indicating whether this instance is currently initialized for encryption or decryption.

Specified by:

getCipherMode in interface EncryptionAlgorithm

Returns:

Cipher.ENCRYPT_MODE, Cipher.DECRYPT_MODE, or 0 if the cipher mode has not been initialized by calling either EncryptionAlgorithm.initEncrypt() or EncryptionAlgorithm.initDecrypt().

getBlockSize

public int getBlockSize()

Gets the block size of the encryption algorithm cipher in bytes.

Specified by:

getBlockSize in interface EncryptionAlgorithm

Returns:

Block size of cipher in bytes, or 0 if the cipher is not a block cipher.

initEncrypt

public void initEncrypt()
                 throws CryptException

Initializes this instance for encryption operations.

Specified by:

initEncrypt in interface EncryptionAlgorithm

Throws:

CryptException - On cryptographic configuration errors.

initDecrypt

public void initDecrypt()
                 throws CryptException

Initializes this instance for decryption operations.

Specified by:

initDecrypt in interface EncryptionAlgorithm

Throws:

CryptException - On cryptographic configuration errors.

encrypt

public byte[] encrypt(byte[] plaintext)
               throws CryptException

Encrypts the given plaintext bytes into a byte array of ciphertext using the encryption key.

Specified by:

encrypt in interface EncryptionAlgorithm

Parameters:

plaintext - Input plaintext bytes.

Returns:

Ciphertext resulting from plaintext encryption.

Throws:

CryptException - On encryption errors.

encrypt

public String encrypt(byte[] plaintext,
                      Converter converter)
               throws CryptException

Encrypts the given plaintext bytes into a ciphertext string using the conversion strategy provided by the given converter.

Specified by:

encrypt in interface EncryptionAlgorithm

Parameters:

plaintext - Input plaintext bytes.

converter - Converter that converts ciphertext output bytes to a string representation.

Returns:

Ciphertext string resulting from plaintext encryption.

Throws:

CryptException - On encryption errors.

encrypt

public void encrypt(InputStream in,
                    OutputStream out)
             throws CryptException,
                    IOException

Encrypts the data in the given plaintext input stream into ciphertext in the output stream. Use Base64FilterOutputStream or HexFilterOutputStream to produce ciphertext in the output stream in an encoded string repreprestation.

Specified by:

encrypt in interface EncryptionAlgorithm

Parameters:

in - Input stream of plaintext.

out - Output stream of ciphertext.

Throws:

CryptException - On encryption errors.

IOException - On stream read/write errors.

decrypt

public byte[] decrypt(byte[] ciphertext)
               throws CryptException

Decrypts the given ciphertext bytes into a byte array of plaintext using the decryption key.

Specified by:

decrypt in interface EncryptionAlgorithm

Parameters:

ciphertext - Input ciphertext bytes.

Returns:

Plaintext resulting from ciphertext decryption.

Throws:

CryptException - On decryption errors.

decrypt

public byte[] decrypt(String ciphertext,
                      Converter converter)
               throws CryptException

Decrypts a string representation of ciphertext bytes into a byte array of plaintext using the decryption key.

Specified by:

decrypt in interface EncryptionAlgorithm

Parameters:

ciphertext - Input ciphertext bytes.

converter - Converter that converts the ciphertext input string into raw bytes required by the cipher algorithm.

Returns:

Plaintext resulting from ciphertext decryption.

Throws:

CryptException - On decryption errors.

decrypt

public void decrypt(InputStream in,
                    OutputStream out)
             throws CryptException,
                    IOException

Decrypts the data in the given ciphertext input stream into plaintext in the output stream. Use Base64FilterInputStream or HexFilterInputStream to consume ciphertext in an encoded string representation.

Specified by:

decrypt in interface EncryptionAlgorithm

Parameters:

in - Input stream of ciphertext.

out - Output stream of plaintext.

Throws:

CryptException - On decryption errors.

IOException - On stream read/write errors.

toString

public String toString()

Overrides:

toString in class AbstractAlgorithm

initCipher

protected void initCipher()
                   throws CryptException

Initializes the underlying Cipher object using AbstractAlgorithm.algorithm, mode, and padding.

Throws:

CryptException - if the algorithm is not available from any provider or if the provider is not available in the environment.

init

protected void init(int encryptOrDecrypt)
             throws CryptException

Initializes cipher for either encryption or decryption.

Parameters:

encryptOrDecrypt - Either Cipher.ENCRYPT_MODE or Cipher.DECRYPT_MODE.

Throws:

CryptException - On cryptographic configuration errors.

crypt

protected byte[] crypt(byte[] in)
                throws CryptException

Based on current cipher mode, encrypts or decrypts the given input data.

Parameters:

in - Cipher input data.

Returns:

Cipher output data.

Throws:

CryptException - On encryption errors.

crypt

protected void crypt(InputStream in,
                     OutputStream out)
              throws CryptException,
                     IOException

Based on current cipher mode, encrypts or decrypts the data in the given input stream into resulting data in the output stream.

Parameters:

in - Input stream.

out - Output stream.

Throws:

CryptException - On encryption errors.

IOException - On stream read/write errors.

getAlgorithmParameterSpec

protected abstract AlgorithmParameterSpec getAlgorithmParameterSpec()

Gets the algorithm parameter specification for this algorithm.

Returns:

Algorithm parameter specification specific to this algorithm.

getChunkSize

protected abstract int getChunkSize()

Gets the chunk size for buffers using in stream-based encryption and decryption operations.

Returns:

Stream chunk size.